DynoHubs: What light bulbs/LED emitters?
(PeteCresswell)
Sturmey-Archer Dynohub?
Front? Back?
I did the thing with the bridge rectifier to convert it's output
to DC - figuring I'd drive some LED emitters to get max light.
But I'm having problems with the voltage regulator part. I get
the circuit tuned to put out, say, 1.5 volts with 6 volts coming
in from a 4-battery test source and then when I put another
battery in series, the output voltage rises to 2.something.
Probably something dumb I'm doing in the regulator, and I expect
to do it right eventually.
But it got me to wondering how voltage-tolerant light bulbs and
LEDs are. My assumption going into this has been "not very",
but I don't have much to base that on.
Am I doing the voltage regulation piece in vain? Do I really
need regulation? When I hang a voltmeter on the DC output it
varies from 3 volts at a walking pace to about 20 volts on a
downhill.
So, bottom line, who is using what without toasting a lot of
bulbs yet getting plenty light?
--
PeteCresswell
Hank
I was a liberal arts major, so I bought a Lumotec IQ Fly , crimped the
spade connectors, and plugged it into my SON. Piece of cake.
It's about as bright as my old 10W battery-powered Halogen NiteRider
system.
(PeteCresswell)
>I was a liberal arts major, so I bought a Lumotec IQ Fly , crimped the
>spade connectors, and plugged it into my SON. Piece of cake.
Well, I majored in accounting.... and kept two checking accounts
so I could use one one month and the other the other month -
letting each run dry so I wouldn't have to deal with balancing a
checkbook.... Finally graduated, but the fact that I did was no
credit to the school...
Having said all that.... Thanks for the terminology. Googling
"Lumotec" led right to Peter White's page dedicated to generator
lighting.
http://www.peterwhitecycles.com/schmidt-headlights.asp
--
PeteCresswell
bob prohaska's usenet account
> Per Hank:
>>I was a liberal arts major, so I bought a Lumotec IQ Fly , crimped the
>>spade connectors, and plugged it into my SON. Piece of cake.
>
> "Lumotec" led right to Peter White's page dedicated to generator
> lighting.
> http://www.peterwhitecycles.com/schmidt-headlights.asp
Bike generators match very well to light emitting
diodes. Here's a account of some experiments I did which you might
find, um, illuminating. [ducking & running]
http://www.zefox.net/~bob/bicycle/
8-)
bob prohaska
Michael Press
"(PeteCresswell)" <x...@y.Invalid> wrote:
> Per Hank:
> >I was a liberal arts major, so I bought a Lumotec IQ Fly , crimped the
> >spade connectors, and plugged it into my SON. Piece of cake.
>
> Well, I majored in accounting.... and kept two checking accounts
> so I could use one one month and the other the other month -
> letting each run dry so I wouldn't have to deal with balancing a
> checkbook.... Finally graduated, but the fact that I did was no
> credit to the school...
How did you know when an account went dry?
--
Michael Press
Andre Jute
In the tradition established in this thread: I was educated as an
economist and psychologist and became an artist who occasionally
publishes books on engineering as well. But I do know a little about
electronics, in that I've worked for fifteen years or so with the
kilovolt thermionic tube amplifiers I design and build.
1. I'm assuming your Sturmey-Archer dynohub is rated the same as every
other dynohub, which is theoretically 6V 0.5A or 3W. It will in fact
probably deliver more as it is built to German regulations that demand
a high percentage of its total output at the equivalent of only 9mph.
2. The standard assignment of this power is 0.6W to the rear light and
2.4W to the front light; this assumes that the front light is halogen
and the rear a red LED, so, if you don't lead any power to the rear,
you can use a 3W front halogen.
3. Forget a dynopowered rear light of any kind. Even the best are
dangerous to your health. The expensive BUMM ones are not watertight
and the best of the rest, made by Basta (I have one they custom make
for Gazelle but it is basically just an aesthetic variation of their
best rear lamp) and by Spanninga (their Ultra; I have that one as
well) are merely better waterproofed, not more illuminative. I keep
them on my bikes simply because they came with the bikes. Even the
best of the dynodriven rear lights are little glimmers that you can
barely see across the street. None of the dyno-driven rear lights
flash, because it is streng verboten to have flashing lights in
Germany and The Netherlands, their prime markets.
4. Get a battery rear light. If you're rich, get a Dinotte rear light
(ask Jay; he has one), if not a Cateye TL-LD1100, which is pricey
enough. There is only one other taillight that is good enough for your
life and that's the Trek Disco Inferno, which is no longer made. The
Dinotte and the Cateye 1100 are *bright*, they cast very substantial
light to the sides as well as the rear, and they flash. Those are the
minimum requirements for good taillights, and they are the only ones
who truly meet them. The Cateye 1100 is bright enough to be seen in
bright sunlight; I use it as a daylight running lamp. It is supposed
to last 200 hours on a set of 2 AA batteries; I don't know how long
the batteries last in hours because I use rechargeables and swap them
out every three or four months or so.
5. Now you're ready to consider your front light. Your dynohub will
power halogen or LED lights that will give substantial light.
6. For a start, if you ride faster than about 10mph, you can fit a
second halogen light and the dynobub will power both of them. A
circuit is on the netsite of a guy who comes to RBT, name of Marten I
think; possibly the firm is called M-Engineering. Peter White also has
a circuit. You don't need the expensive SON lights; all they are are
Bisy lights with switches, or BUMM lights with switches. You can buy
the cheapest BUMM (round) halogen lights and make your own switchbox
-- I made one with a three-position switch (off, one on, both on) in a
plastic pill container and sealed it with superglue and fixed it to
the handbars with a fat rubber band.
7. Or you might want to considering overvolting a single halogen lamp:
you get far more light and you won't blow a Philips MR16 or MR11
longlife unit --anyway, what do you care if you reduce a 3000 mtbf
lamp to 1500 hours of life if you get nearly twice as much light? The
trick is that you must be able to get them in the 6V versions to work
with your dynohub, and the 6V MR16 or MR11 are not easy to find, at
least not where I live. But, once you have the right voltage lamp,
they're incredibly easy to work with. I built a lamp with a common
decorating type of MR16, 12V 20W, by simply soldering wires to the
pins (you can buy plugs for the pins at any lamp store, electrical
goods store or hardware store but they're more expensive than the
lamps themselves which are supermarket items), glueing the lamp into a
small Roma tomato puree can (it is exactly the right size) and glueing
the wires into a hole in the back for strain relief; I overvolted it
with the 14.4V battery from my drill, and fixed it to the handlebars
with a clamp from a throwaway rear light I bought at the pound shop
(US "dime store") specifically for this purpose. It made a stunning
lamp, earning a lot of respect from drivers, and was capable of going
for a ten mile ride on narrow country lanes with the drill battery.
(Eventually I bought readymade lights because the package was cheaper
than buying suitable rechargeable batteries, charger, case and so
on.)
8. Or, in LEDs, you can fit as many low consumption LEDs as you can
power. Each LED drops y volts, so the total must add up to what your
dynohub produces or must be regulated. You might want to look into
buckpucks to get the voltage right. Frankly, I wouldn't mess with LEDs
unless I could get the latest and the best, together with some means
of focusing the light correctly, and were also willing to sacrifice an
existing set of lights with hefty, preferably cast ali, shells for
cooling the LEDs. I looked into LEDs and decided that BUMM's Fly IQ
(at the expensive end of their range, which is generally overpriced)
would probably in the end cost less than messing around trying to make
my own.
9. If you're cheap or poor, consider this. Plenty of RBT dickswingers
will now weight in with how fabulous their BUMM Fly IQ is; I have one
too and it is a good light. However. A couple of halogen 2.4W lamps --
because that is what I had at the time of the test; 2x 3W lights would
do better still -- made as much light as the Fly at any speed over a
crawl and could be better arranged because the two lamps had different
spreads. The problem with a single light, any single light but
especially those driven by dynohubs where the output is by definition
limited, is that it is optimized for some particular patch, and there
isn't enough power to light up everything. With two lights you can
light the hole in front of the bike as well as the distance, and by
angling the two lights carefully either have a smooth spread or
distribute the available light to suit your preference. Example: I
ride on narrow lanes with a high crown and a very sudden drop-off into
the ditch -- I want to see both sides of the lane close to the bike,
and on the downhill i want to see the curves well ahead; no one dynamo
light can do both; in fact, even in big battery lights I use two
separate lamps, each dedicated to one desirable purpose.
10. Lights are the last bicycle frontier. We hear a lot of talk from
the technofreakies about how dynamo lights are now so much better than
they were. But better isn't automatically good enough. The best dyno
front light is still only nearly as good as a 10W MR11 battery light
-- whereas I don't feel comfortable on any aspect of lighting (being
seen, having my space respected, seeing) with anything less than about
25W divided between two lamps. YMMV, of course.
11. In summary: I recommend the Cateye TL-LD1100 battery rear light,
and two cheap BUMM halogen lights driven off the dynamo at the front
with a homemade switch, supplemented in case of regular commuting or
any strenuous riding circumstances by a rechargeable battery front
light set .
12. A simple test of whether lights are good enough is to go to the
most dangerous road you ride on and check when drivers first see you
and how they react. If more than one out of ten drivers don't see you
and react appropriately until you sweep a light directly through his
eyes, the lights are not good enough. The most dangerous road I ride
at night is less than a minute from my house and is ideal for setting
up an experiment because it is dark and has a hill to define the
driver's first sight of the bicyclist. I found that with 10W of
illumination on the bike, drivers 180 yards away did not slow after
the crest, with 15W some slowed, with 25W almost all slowed, and the
idiots would slow instantly if I swept that much light through their
eyes at 100 yards. That's still less than a quarter the light output
of a car putting two 55W beams on high to warn another driver.
13. Good strong lights are useful in daylight too. The flashing Cateye
1100 persuades a lot of people to slow behind me and to give me a
wider berth than they did before I fitted that light. The key for a
cyclist is to be seen and thought about. (When Jay has a bit more
experience with his Electra, he will notice that his higher profile on
the bigger -- and clearly expensive -- bike earns him more courtesy
from drivers than was the case on his old folder.)
14. That applies to front lights as well. Example: Yesterday
afternoon, while I was riding down a hill on another narrow road with
parked cars on both sides, a driver coming from the front clearly
intended, despite the fact that I had right of way, to bull his way
past me by forcing me to stop and pull off. I switched on my front
lights as a warning that I had seen him and had no intention of giving
way, and he immediately had second thoughts, pulling out of my way
between two parked cars to give me the road. A woman who was driving
behind me also drove into the supermarket where I stopped. "You
frightened that pushy son of a bitch shitless," she said, laughing
aloud; it turned out he's her unloved neighbour and people have been
talking about his foul manners on the hill to the estate where they
live.
15. I'm planning on fitting a flashing high-power white or amber LED
at the front, to operate whenever I'm on the bike including daylight,
because the flashing Cateye red at the back has been so successful. I
just haven't worked out yet if it will battery driven or if I should
let the dynohub drive it. An attractive option would be a pair of good
LED lights, with additional electronics to flash one, switched to come
on in steady mode when required.
16. If you buy one of the German or Dutch rear lights I'm advising
against, don't bother to get the self-switching one. I have three, and
I take potluck about when any of them are in manual-on-off or auto-on-
at-dusk mode because I cannot work out how to switch the modes.
Furthermore, one of them at least does not meter light reliably and is
confused by the common sodium type of street lights, and the motion
sensor has been inoperative from new. (By contrast the light sensor on
my Cyber Nexus groupset on my Trek Navigator works flawlessly to
switch on my dynohub-driven front light at dusk and off again at dawn.
Shimano used to make a light sensor/switch combo that reputedly worked
well too with dynohubs, but it is a long time since anyone had stock
of it.)
HTH.
Andre Jute
http://members.lycos.co.uk/fiultra/
"an unbelievably comprehensive web site
containing vital gems of wisdom"
Stuart Perry Hi-Fi News & Record Review
(PeteCresswell)
>How did you know when an account went dry?
I didn't. But alternating checkbooks every month kept the
amount of basic arithmetic necessary to balance to an absolute
minimum.
--
PeteCresswell
Andre Jute
> Fri, 14 Mar 2008 21:05:42 -0700 (PDT), Andre Jute:
>
> >On Mar 14, 8:36 pm, "(PeteCresswell)" <x...@y.Invalid> wrote:
> >> What light bulbs/LED emitters are you powering with your
> >> Sturmey-Archer Dynohub?
> >>
> >> Front? Back?
> >>
> >> I did the thing with the bridge rectifier to convert it's output
> >> to DC - figuring I'd drive some LED emitters to get max light.
> >>
> >> But I'm having problems with the voltage regulator part.
>
> You don't need a voltage regulator - just a bridge rectifier, a smoothing
> capacitor and up to four high-power LEDs (Luxeon Rebel, Luxeon K2, Cree
> XRE, Seoul P4) in series. One of them as a rear light - all with
> apropriate optics and heat sinks.
>
> >> Am I doing the voltage regulation piece in vain? Do I really
> >> need regulation?
>
> No. Any regulation means losses. A classic Sturmey-Archer Dynamohub
> delivers 300mA. If you only use LEDs which can cope with 300mA you are
> fine.
>
> >In the tradition established in this thread: I was educated as an
> >economist and psychologist and became an artist who occasionally
> >publishes books on engineering as well. But I do know a little about
> >electronics
>
> So - why do you answer?
You're having a linguistic misunderstanding, Andreas. I made a joke.
I've been in electronics of a far more rigorous nature than little
bicycle lamps for many years. I told you so in my first post, but to
make your contrary point you cut away my text: "I've worked for
fifteen years or so with the kilovolt thermionic tube amplifiers I
design and build." That means I routinely work with a thousand volts
or more.
> >1. I'm assuming your Sturmey-Archer dynohub is rated the same as every
> >other dynohub, which is theoretically 6V 0.5A or 3W.
>
> This is wrong for the classic Dynahub, which is rated 6V-1.8W.
Thanks. See, that's why I state my assumption, so that if wrong it may
be corrected by those who know better.
> >3. Forget a dynopowered rear light of any kind.
>
> Stupid advice.
Let's see.
> >Even the best are
> >dangerous to your health. The expensive BUMM ones are not watertight
>
> Millions of BUMM rear lights are used in Germany and the Netherlands.
> Water problems with their rear lights are very rare.
Of course you're right. But in Germany and The Netherlands (note
capitalization in English) the dealer and the manufacturer are down
the road, in the US it is not so easy to get service, in parts of the
US as we have heard recently conditions in winter are atrocious, and,
anyway, why buy a light that is inadequate for local conditions
(regardless of how well it sells at home) if in addition the makers
cannot be bothered to make it watertight?
> Problems with empty batteries in any kind of mobile device are more than
> common. Most battery power LED rear lights don't last more than 20 hours
> (some even less than 10h) until light output starts to drop.
It would be interesting if you were to test the Spanninga Ultra and
the Cateye TL-LD1100, both said to have longevity in three figures
from a set of batteries.
In any event, that is why I recommend having two sets of lights front
and rear. It should be clear from the rest of this why I consider the
dynohub and its lights a worthwhile permanent backup system.
> >flash, because it is streng verboten to have flashing lights in
> >Germany and The Netherlands, their prime markets.
>
> Flashing lights should be reserved for special unusual situations. With
> everyone around flashing bright - everyone will be anoyed.
You haven't put your mind in gear, Andreas. That may apply to the
Germany and The Netherlands, where there are hordes of cyclists and
the attitude of drivers is different. It doesn't apply where I live,
it doesn't apply in the States. The cyclist on the road is minority
exception here and in the States, not the majority, not even even a
substantial presence. Think the matter through and you will see the
sense of a flashing light to announce the exception -- the fact that
the bicyclist in your words is a "special unusual situation".
> >-- I made one with a three-position switch (off, one on, both on) in a
> >plastic pill container and sealed it with superglue and fixed it to
> >the handbars with a fat rubber band.
>
> Wasn't it you who prefered watertight lighting devices? "Superglue" will
> degrade soon when confronted with water for longer times.
So what? I made a temporary prototype to see how various types of DIY
lights worked. A few days later I had a watertight switch delivered
from RS. Whatever makes you think I would make a makeshift permanent?
Do you perpetrate that sort of slack engineering?
> >7. Or you might want to considering overvolting a single halogen lamp:
> >you get far more light and you won't blow a Philips MR16 or MR11
>
> Houshold lights with rotational symmetric optics are not appropriate for
> vehicle applications.
Really? You should tell that to the makers of hundreds of types of
bike lights made with MR11 lamps. You can't tell that to me, and be
believed, because I have MR11 lamps (made by One Electron) on my bike
that work a treat, the prototypes I built were MR16 and worked
brilliantly, and MR16 lamps are found on auxiliary lamps for
automobiles that I notice are TUV approved. You're talking through the
back of your neck, Andreas. Perhaps you have a commercial connection
that inspires these distortions?
>Anyway: There are no "MR16" or "MR11" lamps
> available which are designed to be driven with the 300mA of a Dynohub.
> Something more efficient should be choosen.
At this point I was clearly talking about driving lights with
batteries. Again, for you to make your spurious contrary point, you
cut away the relevant bit of my text: "I overvolted it with the 14.4V
battery from my drill".
> >8. Or, in LEDs, you can fit as many low consumption LEDs as you can
> >power. Each LED drops y volts, so the total must add up to what your
> >dynohub produces or must be regulated. You might want to look into
> >buckpucks to get the voltage right.
>
> Unneccesary for Dynohub use.
Which part is "unnecessary", Andreas? The buckpuck, or seriesing up
the voltages? You have to be more precise: Pete wouldn't ask if he
didn't know.
> > I looked into LEDs and decided that BUMM's Fly IQ
>
> A wise choice. The Fly IQ should work also with the Dynohub.
>
> >9. If you're cheap or poor, consider this. Plenty of RBT dickswingers
> >will now weight in with how fabulous their BUMM Fly IQ is; I have one
> >too and it is a good light. However. A couple of halogen 2.4W lamps --
> >because that is what I had at the time of the test; 2x 3W lights would
> >do better still
>
> This won't work with a 1.8 Watt SA Dynohub.
See point 1 above. And perhaps someone should draw a conclusion for
Pete: LEDs are more efficient than halogen lights, the best halogen
lights assume at least 2.4W available, so the SA will give best value
with LED lights.
> > -- made as much light as the Fly at any speed over a
> >crawl and could be better arranged because the two lamps had different
> >spreads.
>
> Than - try two Fly IQs. Could be used in parallel (at slow speeds) or in
> series (at higher speeds).
This is getting pretty pricey, Andreas. And the electronics are
getting tricky, or the switching cumbersome (and expensive in itself
-- check the prices of quality switches, never mind waterproof ones).
> >10. Lights are the last bicycle frontier. We hear a lot of talk from
> >the technofreakies about how dynamo lights are now so much better than
> >they were. But better isn't automatically good enough. The best dyno
> >front light is still only nearly as good as a 10W MR11 battery light
> >-- whereas I don't feel comfortable on any aspect of lighting (being
> >seen, having my space respected, seeing) with anything less than about
> >25W divided between two lamps. YMMV, of course.
>
> Why can millions of people ride save with dynamo light sets in central
> Europe but you can't?
Because their situation is different. There are more cyclists, so
drivers expect them. I am a lone cyclist in a sea of cars; no one
expects me.
>Maybe your behaviour or your risk perception should
> be altered.
You're an arrogant son of a bitch, aren't you, telling me to stay off
the roads and lower the value I put on my life and limb.
> >12. A simple test of whether lights are good enough is to go to the
> >most dangerous road you ride on and check when drivers first see you
> >and how they react. If more than one out of ten drivers don't see you
> >and react appropriately until you sweep a light directly through his
> >eyes, the lights are not good enough. The most dangerous road I ride
> >at night is less than a minute from my house and is ideal for setting
> >up an experiment because it is dark and has a hill to define the
> >driver's first sight of the bicyclist. I found that with 10W of
> >illumination on the bike, drivers 180 yards away did not slow after
> >the crest,
>
> Why should a driver which sees your 10W front light reduce his speed?
Your assumption that drivers noticed my 10W light is unwarranted. The
proper assumption from the complete results of the test is that
drivers simply did not see or notice 10W of light, certainly not as a
reason to take care.
10W is the maximum subjectively equivalent light output of a Fly IQ.
It is not good enough.
> He is on the other lane - isn't he?
That's another entirely unwarranted assumption you're making, Andreas.
This point illustrates why your kneejerk judgements, about how I
should ride and how highly I should value my life (or, by implication,
Pete should), are totally cockeyed.
This is a one-and-a-half car-width leafy residential country lane
between large houses on large pieces of land. When I lived on this
road I went up it at 70mph in the car, but would slow right down to
pass another car because both had to go into the ditch with the wheels
on one side. A driver cannot pass a cyclist going in the opposite
direction at speed: there isn't space because at speed the car has to
stay in the middle of the road. That is why it is essential for the
driver to see the cyclist immediately the driver crests the hill at
the top.
> > with 15W some slowed, with 25W almost all slowed,
>
> You are a real hero if you blind uncoming drivers/cyclists with your
> battery lights without a clear cutoff above the horicon...
Once more you're making an entirely unwarranted hostile assumption,
Andreas. Where does it say I use 15W or 25W lights to blind drivers
who drive considerately? Or, are you assuming, like your stupid
legislators, that anything more than a little glimmer on a bike will
always blind a driver? "Stupid" because cars are permitted lights so
much stronger than bicycles. What natural order of things makes a
bicyclist a lesser human being than a motorist?
As for your remark "without a clear cutoff above the horicon", this is
just dumb prejudice or commercial interest speaking. If the same
lights are good enough to be approved at much higher intensities (50W)
for car auxiliary lights, they're good enough for bicycles.
> > and the
> >idiots would slow instantly if I swept that much light through their
> >eyes at 100 yards. That's still less than a quarter the light output
> >of a car putting two 55W beams on high to warn another driver.
>
> Usually the high beam is dipped when another vehicle comes to sight. How
> do you dip your lights?
Simple. I have two lights, differently aimed, with switches under my
thumb. I dim the lights by switching off the strong one which throws
well to the front but downwards and just slightly off the centre away
from oncoming traffic, leaving only the one which throws directly in
front of the bike and well to the ditch/pavement side. This is pretty
obvious for anyone who puts his mind in gear instead of assuming the
way a bunch of Germans and Dutchmen do it is automatically right; even
the thoughtful Dutch and German know they do it only because a bunch
of legislators got it wrong at a time when a big Mercedes had only a
little over 100PS (horsepower to the Americans) and there were many,
many fewer cars on the roads.
Notice that my lights are considerate of fellow roadusers in cars. I
have to commit two separate deliberate actions to flash someone who is
endangering me: I have to switch on the high light, and, if he still
doesn't react, I have to turn the handlebars to sweep his passenger
cabin briefly. Note further that I have immediately to turn the
handlebars back to keep riding straight; a reflex action. He sees the
full light only for a fraction second, but the weave identifies a
bicycle as well as locating it.
> >13. Good strong lights are useful in daylight too. The flashing Cateye
> >1100 persuades a lot of people to slow behind me and to give me a
> >wider berth than they did before I fitted that light. The key for a
> >cyclist is to be seen and thought about.
>
> To be seen mostly belongs on a clear position on the road (read john
> Forsteres Cyclecraft) - not on flashing like a cristmas tree.
I repeat: you are talking about drivers who expect to see bicyclists,
who have experience with bicyclists, and whose laws give bicyclists
rights (so do mine, actually, but knowledge of the law is low and
application in the courts hostile to bicyclists). I ride among
motorists who consider that a bicyclist should pull off the road when
he sees them coming; I discover that time and again when I stop them
and listen to their excuses for driving dangerously around me. About
twice a year someone shouts at me on a suburban street. "Get off the
roads." That doesn't mean, Get out of my way, it means, Bicycles do
not belong on the road.
We started out where you do not think I am entitled to an opinion
because I was trained as a psychologist. Well, it seems to me, as a
psychologist, that a flashing light is, in addition to correct riding
position, an incremental statement that you value your life, that you
want motorists to notice you (that's care for their insurance costs
and car repair bills and consciences), and that you are prepared to do
something about it. Cheap cracks about "flashing like a christmas
[sic] tree" don't change the fundamental fact that by forbidding
flashing lights German and Dutch law deprives the cyclist of an
effective means of protecting his life.
****There is no, repeat no, German or Dutch rear light which comes
within miles of the light output of a Cateye TL-LD1100 in its steady
mode, and in addition the Cateye has the even more visible flashing
modes. The Cateye is Japanese made. The only other easily available
rear light that actually makes you visible is a Dinotte, made in the
USA.****
> >16. If you buy one of the German or Dutch rear lights I'm advising
> >against, don't bother to get the self-switching one.
>
> What should be the adavantage of a "self switching" rear light, when
> everything is driven by the dynamo?
Hallelujah, we agree on something! It doesn't matter to a rear LED
light with an almost infinite lifespan, which can just be left on if
it is driven by a dynohub, which is why I say don't bother to pay
extra for self-switching.
> Andreas
In short, while German and Dutch dynohub LED lights at the front are
getting better, they are still not a complete solution to lighting
problems elsewhere in the world where bicycling conditions are
different; it would help if export models had a flashing mode. German
and Dutch rear lights, either battery or dynohub driven, are entirely
inadequate for conditions where cyclists are in a minority. What is
required for a bicycle rear light is a strong light (check out the
Cateye and Dinotte mentioned above) with a lot of sidethrow (check
out the Cateye and Dinotte mentioned above), and a flashing mode or
modes (check out the Cateye and Dinotte mentioned above) is
absolutely essential.
Now we can reevaluate this:
> >3. Forget a dynopowered rear light of any kind.
>
> Stupid advice.
Not "stupid" at all, now that we've analysed Andreas's assumptions
(including the many wrong ones) and arguments.
I don't have any connection whatsoever with Cateye or Dinotte, or BUMM
or Spanninga, or Gazelle or Trek, or Basta.
Andre Jute
http://members.lycos.co.uk/fiultra/BICYCLE%20%26%20CYCLING.html
frkr...@gmail.com
> Andreas Oehler <andreas.oeh...@gmx.de> wrote:
> >
> > Millions of BUMM rear lights are used in Germany and the Netherlands.
> > Water problems with their rear lights are very rare.
>
> Of course you're right. But in Germany and The Netherlands (note
> capitalization in English) the dealer and the manufacturer are down
> the road, in the US it is not so easy to get service, in parts of the
> US as we have heard recently conditions in winter are atrocious, and,
> anyway, why buy a light that is inadequate for local conditions
> (regardless of how well it sells at home) if in addition the makers
> cannot be bothered to make it watertight?
If, as Andreas states, water problems with these lights are very rare,
then Andre's final question is pointless. Instead of begging the
question, Andre should provide some evidence that the millions of
Germans and Dutch using these lights somehow haven't noticed that they
don't work in their rainy weather. Of course, that might be
difficult!
> > Flashing lights should be reserved for special unusual situations. With
> > everyone around flashing bright - everyone will be anoyed.
>
> You haven't put your mind in gear, Andreas. That may apply to the
> Germany and The Netherlands, where there are hordes of cyclists and
> the attitude of drivers is different. It doesn't apply where I live,
> it doesn't apply in the States. The cyclist on the road is minority
> exception here and in the States, not the majority, not even even a
> substantial presence. Think the matter through and you will see the
> sense of a flashing light to announce the exception -- the fact that
> the bicyclist in your words is a "special unusual situation".
Here in the US, the twinkling or flashing LED taillight has become the
nighttime signature of a cyclist (or at least, the subset that bothers
with lights at all). This has nothing much to do with driver
attitudes. It's simply because the brief flashing action allowed LEDs
to be bright while reducing battery drain, all at low expense. The
inexpensive LED units became so popular, they are now universally
recognized.
I don't find the flashing or twinkling (depending on the specific
unit) to be annoying. However, that's primarily because the intensity
is not out of control. Super-bright lights with bad optics can be
very annoying and very hard on everyone's nighttime vision, especially
if they flash.
> > Houshold lights with rotational symmetric optics are not appropriate for
> > vehicle applications.
>
> Really? You should tell that to the makers of hundreds of types of
> bike lights made with MR11 lamps. You can't tell that to me, and be
> believed, because I have MR11 lamps (made by One Electron) on my bike
> that work a treat, the prototypes I built were MR16 and worked
> brilliantly, and MR16 lamps are found on auxiliary lamps for
> automobiles that I notice are TUV approved. You're talking through the
> back of your neck, Andreas. Perhaps you have a commercial connection
> that inspires these distortions?
I agree with Andreas: rotationally symmetric beams on a road vehicle
are, at best, crude and ham-fisted. Their popularity with certain
unsophisticated consumers doesn't change that fact.
You simply don't need as much light going up into the sky as you need
downward onto the road; it's a waste. That should be obvious to
anyone. To put a finer point on it, it's better to have more
intensity closer to the horizon, to shine further down the road, and a
bit less to shine directly in front of the bike. You see an example
by shining your car's or motorcycle's headlamp at a wall. This optical
sophistication of a proper road light is a long way from the fuzzy
ball of light emitted by an MR bulb.
MR bulbs are designed for pattern-free illumination for overhead
projectors and for your wife's interior decorations, not for road
vehicles. No well-designed vehicle lights use them. Advocating them
for a bicycle - a vehicle whose reason for being is efficiency - is
silly.
> > Why can millions of people ride save with dynamo light sets in central
> > Europe but you can't?
>
> Because their situation is different. There are more cyclists, so
> drivers expect them. I am a lone cyclist in a sea of cars; no one
> expects me.
The "Omigod, cycling is REALLY dangerous HERE!!!!!!" stuff gets very
tiresome.
Most of my night riding is in a city and suburb where I am the lone
night cyclist. But I've just returned from a vacation to a place
where cycling (including at night) is _extremely_ popular, and I've
ridden in places that completely span those extremes.
With one exception, I've never been in a place where a legally lit
cyclist is not sufficiently conspicuous. I've satisfied myself
literally hundreds of times that I'm even more visible at night than I
am in daytime. (Coincidentally, a friend once told me he rides his
motorcycle only at night, for that reason.)
But like most cyclists, I am comfortable enough with my daytime
visibility. Unlike most cyclists, I've also verified my nighttime
visibility in various tests and workshops, in various street
conditions, using other motorists and cyclists as helpers. In all but
one situation, everyone participating has agreed that bog-standard
bike lights and reflectors are all that's necessary.
The exception? Riding in heavy fog in an environment where motorists
overdrive their headlights. Sadly, you will always have a contingent
of motorists who think 70 mph on country lanes in the fog is somehow
reasonable. Thick fog is the only time I actually obey the simple-
minded advice to "ride as if I'm invisible."
> You're an arrogant son of a bitch, aren't you...
:-) Unintended irony at its best!
- Frank Krygowski
Andre Jute
> On Mar 15, 1:10 pm, Andre Jute <fiul...@yahoo.com> wrote:
> > Andreas Oehler <andreas.oeh...@gmx.de> wrote:
> > >
> > > Millions of BUMM rear lights are used in Germany and the Netherlands.
> > > Water problems with their rear lights are very rare.
> >
> > Of course you're right. But in Germany and The Netherlands (note
> > capitalization in English) the dealer and the manufacturer are down
> > the road, in the US it is not so easy to get service, in parts of the
> > US as we have heard recently conditions in winter are atrocious, and,
> > anyway, why buy a light that is inadequate for local conditions
> > (regardless of how well it sells at home) if in addition the makers
> > cannot be bothered to make it watertight?
>
> If, as Andreas states, water problems with these lights are very rare,
> then Andre's final question is pointless. Instead of begging the
> question, Andre should provide some evidence that the millions of
> Germans and Dutch using these lights somehow haven't noticed that they
> don't work in their rainy weather.
I didn't say "millions of Germans and Dutch using these light somehow
haven't noticed that they don't work in rainy weather" -- you're
trying to put words in my mouth Krygo and then demanding I prove
something I didn't say. It is primary school debating trick, about the
level of your mentality.
> Of course, that might be
> difficult!
Not difficult at all, Krygo: I'll do better than that. Here is
evidence that an official independent body, the Dutch Cyclists'
Association
http://www.fietsersbond.nl/urlsearchresults.asp?itemnumber=3061&viewtype=popup
found the B&M (BUMM) D'Toplight Plus to have "low watertightness", in
Dutch "Enige minpunt is de lage waterdichtheid," (Ideomatically
translated as, "One negative mark is the lack of water resistance.")
> > > Flashing lights should be reserved for special unusual situations. With
> > > everyone around flashing bright - everyone will be anoyed.
> >
> > You haven't put your mind in gear, Andreas. That may apply to the
> > Germany and The Netherlands, where there are hordes of cyclists and
> > the attitude of drivers is different. It doesn't apply where I live,
> > it doesn't apply in the States. The cyclist on the road is minority
> > exception here and in the States, not the majority, not even even a
> > substantial presence. Think the matter through and you will see the
> > sense of a flashing light to announce the exception -- the fact that
> > the bicyclist in your words is a "special unusual situation".
>
> Here in the US, the twinkling or flashing LED taillight has become the
> nighttime signature of a cyclist (or at least, the subset that bothers
> with lights at all). This has nothing much to do with driver
> attitudes.
Who said it did, Krygo?
>It's simply because the brief flashing action allowed LEDs
> to be bright while reducing battery drain, all at low expense. The
> inexpensive LED units became so popular, they are now universally
> recognized.
Who said we're talking about about cheap blinkies? I'm recommending
two expensive flashing lights, the Dinotte and the top of the Cateye
range, the TL-LD1100. What's more, I specifically said that the cheap
shit you're talking about is not good enough. Stop trying to force a
discussion that is clearly over your head into something you can
understand.
> I don't find the flashing or twinkling (depending on the specific
> unit) to be annoying. However, that's primarily because the intensity
> is not out of control. Super-bright lights with bad optics can be
> very annoying and very hard on everyone's nighttime vision, especially
> if they flash.
> > > Houshold lights with rotational symmetric optics are not appropriate for
> > > vehicle applications.
> >
> > Really? You should tell that to the makers of hundreds of types of
> > bike lights made with MR11 lamps. You can't tell that to me, and be
> > believed, because I have MR11 lamps (made by One Electron) on my bike
> > that work a treat, the prototypes I built were MR16 and worked
> > brilliantly, and MR16 lamps are found on auxiliary lamps for
> > automobiles that I notice are TUV approved. You're talking through the
> > back of your neck, Andreas. Perhaps you have a commercial connection
> > that inspires these distortions?
>
> I agree with Andreas: rotationally symmetric beams on a road vehicle
> are, at best, crude and ham-fisted. Their popularity with certain
> unsophisticated consumers doesn't change that fact.
Yawn. True to your dishonest form, Krygowski, you've cut away the part
of my letter which makes clear that what Andreas is doing is saying:
These lights made by BUMM are good enough for Germans, so they should
be good enough for you, and me saying, Bullshit.
Furthermore, if the legislators see fit to license lights, and I can
see they deliver more light than other lights, why should I, or anyone
else, not have the better lights rather than risk our lives on the
lesser output of lights a couple of internet clowns, one of them with
suspect commercial connections, want to push because they are on a
crusade against battery lights?
> You simply don't need as much light going up into the sky as you need
> downward onto the road; it's a waste. That should be obvious to
> anyone.
Another straw man argument. Remember, I've built those lights, and
used bought ones? I know that you point them downwards and most of the
light goes where it is wanted, in an oval on the road, with some
spilling onto the close hedge beside the road for orientation.
Whatever you're talking about, Krygo, might go down well with your
claque of the thicker apprentices but not with anyone who has
experience or his brain in gear and the faintest whiff of science in
his education.
>To put a finer point on it, it's better to have more
> intensity closer to the horizon, to shine further down the road, and a
> bit less to shine directly in front of the bike.
I want both and I get it, and enough of it with battery lights. The
point about the best and most expensive of those dynohub lights is
that none of them put out enough light. Let me repeat that: there is
no dynohub light that puts out enough light for any but the most
undemanding circumstances, like riding on the sidewalk or perhaps on
quiet, lit streets (where streetlight show you the gutter, because
most of those mickey mouse dynohub lights have a big hole in front of
the bike and zero spread of light close to the bike).
> You see an example
> by shining your car's or motorcycle's headlamp at a wall.
I don't have a car or a motorcycle, Krygo, and haven't since 1992. I'm
a responsible world citizen. Are you?
>This optical
> sophistication of a proper road light is a long way from the fuzzy
> ball of light emitted by an MR bulb.
Really? On the best European cars perhaps. My memory of American cars
is that they have useless lights.
In any event, what is the relevance of car lights to bicycle lights?
This is just so much smoke. The fact remains that dynohub lamps do not
put out as much light as a suitable battery light.
And MR lamps do not emit fuzzy light when you get into the wattages I
use; you must have cheaped out with the miserable low-wattage MR
lamps, Krygo, or skimped on overvolting them, or just not understood
what you were dealing with. Or, even more despicably, you're talking
crap without any experience at all. With which of these depressing
alternatives are you wasting my time this time?
> MR bulbs are designed for pattern-free illumination for overhead
> projectors and for your wife's interior decorations, not for road
> vehicles. No well-designed vehicle lights use them.
You cut away the bit where I said I saw MRxx auxiliary lights
certified by the TUV, the strictest of all the licensing bodies, for
use in Germany. Whether "well designed vehicles use them", meaning
cars, is an irrelevance, a smoke screen. What is relevant is that MRxx
put more light on the road than a Fly IQ, which is currently the best
of the dynohub lights.
And, of course, battery lights put the same amount of light on the
road when you're going slowly or standing still for however long.
Dynohub lights dim when you slow or die when you stop, or if fitted
with a capacitor burn for some short period of time.
>Advocating them
> for a bicycle - a vehicle whose reason for being is efficiency - is
> silly.
Says Frank Krygowski. That's a recommendation to do the opposite of
whatever Krygo recommends -- that way you can't go wrong.
>a bicycle - a vehicle whose reason for being is efficiency
Crap. The raison d'etre of bicycle is transport. What the owner uses
it for is at his own option. It is only the fascist racing faction of
cyclists who think every bicycle should be about efficiency. Thank God
they're in the minority or cycling might become really unpleasant.
> > > Why can millions of people ride save with dynamo light sets in central
> > > Europe but you can't?
> >
> > Because their situation is different. There are more cyclists, so
> > drivers expect them. I am a lone cyclist in a sea of cars; no one
> > expects me.
>
> The "Omigod, cycling is REALLY dangerous HERE!!!!!!" stuff gets very
> tiresome.
Where did you hear "Omigod, cycling is REALLY dangerous HERE!!!!!!",
dickhead? Not from me you didn't. Again, you, Frank Krygowski, have
dishonestly cut away the context from my previous post so that you can
make a point totally at variance with what I actually said. Your
methods are puerile, Krygo; trying to make me discuss something I
neither said nor intended is a contemptibly transparent debating
trick. Shove it up your ass, sonny.
> Most of my night riding is in a city and suburb where I am the lone
> night cyclist. But I've just returned from a vacation to a place
> where cycling (including at night) is _extremely_ popular, and I've
> ridden in places that completely span those extremes.
Congratulations. So what?
> With one exception, I've never been in a place where a legally lit
> cyclist is not sufficiently conspicuous. I've satisfied myself
> literally hundreds of times that I'm even more visible at night than I
> am in daytime. (Coincidentally, a friend once told me he rides his
> motorcycle only at night, for that reason.)
This is getting more and more ridiculous. Soon, dear old Krygo, you
will tell us that you feel quite safe at the new moon with a totally
dark bicycle, which of course you ride helmetless and stark naked.
Pull the other-- er, well, don't pull anything, you'll get that wrong
too, and embarrass us all.
> But like most cyclists, I am comfortable enough with my daytime
> visibility.
"Like most cyclists" is a statement that requires proof. And even when
you prove it, why should that have the slightest influence on me, or
anyone else who believes that it is worth going the extra half inch?
Since when is "the lowest common denominator approves" a
recommendation, or even good logic: of course the lowest common
denominator approves; that is how it became the lowest common
denominator.
As for your personal opinion, you have zero credibility with me,
Krygo. You're an idiot and a fool, and an opinionated fool at that,
which makes you dangerous to yourself and to anyone who listens to
you.
> Unlike most cyclists, I've also verified my nighttime
> visibility in various tests and workshops, in various street
> conditions, using other motorists and cyclists as helpers.
You mean they were looking for you? That invalidates the test right
there. Why are you wasting my time with this crap, Krygo? If anyone
else put up that tacky, hollow argument, the better educated guys in
your gang would be all over him, so why do you think you'll get away
with it.
> In all but
> one situation, everyone participating has agreed that bog-standard
> bike lights and reflectors are all that's necessary.
You must clearly value your life very little, Krygowski. Perhaps
you're right; ask your wife. You and Andreas, who wants me to lower
the value I put on my life, should get together. You'd make a fine
pair of lowballers.
> The exception? Riding in heavy fog in an environment where motorists
> overdrive their headlights. Sadly, you will always have a contingent
> of motorists who think 70 mph on country lanes in the fog is somehow
> reasonable. Thick fog is the only time I actually obey the simple-
> minded advice to "ride as if I'm invisible."
>
> > You're an arrogant son of a bitch, aren't you...
>
> :-) Unintended irony at its best!
Once again this poor dumb wannabe polemicist Frank Krygowski has cut
away my text and context to make his own utterly irrelevant hostile
point.
Here's what really went down:
Andre Jute wrote:
> Because their situation [in Germany and The Netherlands} is different.
>There are more cyclists, so
> drivers expect them. I am a lone cyclist in a sea of cars; no one
> expects me.
Andreas Oehler replied impertinently:
> >Maybe your behaviour or your risk perception should
> > be altered.
Andre Jute wrote:
> You're an arrogant son of a bitch, aren't you, telling me to stay off
> the roads and lower the value I put on my life and limb.
But the public laughingstock Frank Krygowski thinks that no one will
notice he hacked the context about to make his stupid little joke, and
then like a bad comedian added an unnecessary smiley and exclamation
mark to tell the whole world it is a joke, just in case they don't get
it:
> > You're an arrogant son of a bitch, aren't you...
>
> :-) Unintended irony at its best!
No, Krygo, you missed the point, as you always do: a gentleman never
offends anyone unintentionally. (That sentence is ironical too, though
not in a way you will ever understand, dear Krygo.) Not just one irony
but layers of ironies were intended, and delivered, and understood
where it matters, which isn't with you. So why don't you, dear Krygo,
butt out before you become the butt of the joke.
> - Frank Krygowski
Andre Jute
Who doesn't make unintentional jokes
frkr...@gmail.com
of his ever-expanding tirades of insults. In the interest of brevity,
I'll respond to only a few points:
> <frkry...@gmail.com> wrote:
> >
>
> > Here in the US, the twinkling or flashing LED taillight has become the
> > nighttime signature of a cyclist (or at least, the subset that bothers
> > with lights at all). This has nothing much to do with driver
> > attitudes.
>
> Who said it did, Krygo?
It was silly of you to challenge me on that paragraph, Andre. The
point of the paragraph was that I disagreed with Andreas on the issue
of flashing lights. You should have simply agreed with me.
Unfortunately, your bile overwhelmed you again. Calm down.
> > I agree with Andreas: rotationally symmetric beams on a road vehicle
> > are, at best, crude and ham-fisted. Their popularity with certain
> > unsophisticated consumers doesn't change that fact.
>
> Yawn. True to your dishonest form, Krygowski, you've cut away the part
> of my letter which makes clear that what Andreas is doing is saying:
> These lights made by BUMM are good enough for Germans, so they should
> be good enough for you, and me saying, Bullshit.
I'm sorry if my trimming for brevity confuses you. I thought there
was only one poster here who couldn't understand that standard
practice.
However, while you have complained about others putting words in your
mouth, you seem to be doing the same regarding Andreas. His question
and suggestion were much more gentle than your distorted claim. The
original was:
"Why can millions of people ride [safely] with dynamo light sets in
central
Europe but you can't? Maybe your behaviour or your risk perception
should
be altered." [I think I've properly corrected his original "save",
in brackets.]
And indeed, it is a valid question. It's not uncommon for people in a
non-bicycling culture to have exaggerated ideas of bicycling danger,
and to contend that only extraordinary equipment can make one safe.
Perhaps you do need to revise your cycling behavior, if it's really
risky, or revise your perceptions, if they're really so fearful. It's
not that bad out there.
> > You simply don't need as much light going up into the sky as you need
> > downward onto the road; it's a waste. That should be obvious to
> > anyone.
>
> Another straw man argument. Remember, I've built those lights, and
> used bought ones?
As have I. And I've ridden with others who used them. And we've
examined their strengths and weaknesses. A workshop on bike lights
can be very educational.
> I know that you point them downwards and most of the
> light goes where it is wanted, in an oval on the road, with some
> spilling onto the close hedge beside the road for orientation.
Here's the problem with that strategy: The symmetrical beam of a non-
road-specific light (like an MR-16 or MR-11) is brightest at its
center. If you tilt the lamp to prevent shooting lumens at the stars,
you've got an overly bright patch of pavement close to the front of
your bike. This affects your night vision, in effect burning out much
of your peripheral vision. Furthermore, the beam doesn't penetrate
very far down the road, because the part that's left pointed down the
road is relatively dim.
Again, for road work you need moderate beam intensity closer to the
vehicle, since the distances, angles and visual requirements are all
not very extreme; you can make use of higher beam intensity close to
the horizon, to allow you to see further down the road; and you need
much, much less beam intensity above the horizon, since the light
hitting drivers' eyes comes direct from your lamp. It's very visible
to them without requiring much power.
Some trials with different equipment, with the help of some friends,
should make all that clear.
> >To put a finer point on it, it's better to have more
> > intensity closer to the horizon, to shine further down the road, and a
> > bit less to shine directly in front of the bike.
>
> I want both and I get it, and enough of it with battery lights.
And that's fine. I prefer generator lights because there is no hassle
about tending or replacing or charging or remembering batteries. My
bike is always ready to ride at night, at a moment's notice. I also
find the reliability is significantly higher in other ways.
However, I've long been amazed that optics are excellent in most
generator headlamps; optics are very good to excellent in many low-end
bike headlamps powered by disposable cells; but optics are almost
always junk in the pricey rechargeable bike lights. The design
philosophy seems to be "We got us a good battery, so it doesn't matter
where the light goes; we'll just pump out a lot of it." It's a
caveman approach to design.
If I were to go back to battery powered lights, I think I'd still use
a generator headlamp and power it with a battery. (In fact, I have
one friend who has used that strategy.)
> The point about the best and most expensive of those dynohub lights is
> that none of them put out enough light. Let me repeat that: there is
> no dynohub light that puts out enough light for any but the most
> undemanding circumstances, like riding on the sidewalk or perhaps on
> quiet, lit streets
Absolutely false. Nearly half the American RUSA contingent in the
last Paris-Brest-Paris competition used dynamo lights. And a post-
ride survey showed they were more satisfied with their lights than the
battery-powered group. See http://www.vintagebicyclepress.com/BQPBPEquipsurvey.pdf
I think most would agree Paris-Brest-Paris is a bit more extreme than
sidewalk riding.
> > You see an example
> > by shining your car's or motorcycle's headlamp at a wall.
>
> I don't have a car or a motorcycle, Krygo, and haven't since 1992. I'm
> a responsible world citizen. Are you?
:-) Were you a "responsible world citizen" when you drove your car 70
mph on a very narrow country lane, as you bragged? Or did the
authorities decide to make a responsible citizen out of you by
removing your operator's license for that offense?
In any case, you must be on speaking terms with _someone_ who owns a
modern car or motorcycle. Ask them to shine the headlights at a wall
for you. Note the efficient shape of the beam, the cutoff above the
horizon, the brighter intensity near the horizon.
> In any event, what is the relevance of car lights to bicycle lights?
The relevance is that car lights, and motorcycle lights, and even
moped and scooter lights, are designed to illuminate the road
efficiently without blinding other road users. Good quality bike
lights should do the same. In fact, given the practical necessity for
efficiency on a bike, they should pay even more attention to optics.
Pumping out unfocused mega-lumens (at cost of battery size, weight and
life) is like using 1/8" diameter spokes made of mild steel. It's
primitive and inefficient.
> ...you're talking crap ...
>
> Crap.
>
> ...dickhead...
>
> ... Shove it up your ass, sonny.
>
> You're an idiot and a fool...
>
> ... crap...
>
> ... poor dumb wannabe
>
> ... son of a bitch, aren't you...
>
> ... butt out...
Andre, many of use know your style is to try to "win" by being
unbearably obnoxious. When we stop responding to you, as I will now,
it's not because your intellect has triumphed. It's because your
verbal diarrhea is too ugly to bother with.
- Frank Krygowski
Ozark Bicycle
< Krygo babble snipped for brevity>
(Written to Andre Jute)
> When we stop responding to you, as I will now,
> it's not because your intellect has triumphed. It's because your
> verbal diarrhea is too ugly to bother with.
>
Good Gawd, Franky!!! You really are totally lacking even a semblance
of self-awareness, aren't you?
Andre Jute
<frkr...@gmail.com> wrote:
> When we stop responding to you, as I will now,
> it's not because your intellect has triumphed. It's because your
> verbal diarrhea is too ugly to bother with.
Run, rabbit, run.
Below is Krygo's post in full for students of irony. One has to wonder
how long since there has been a mirror in Krygo's house: ten years
since he split the last one? I don't suppose Krygo can even spell
"intellectual dishonesty".
Andre Jute
Darwin's little helper
> battery-powered group. Seehttp://www.vintagebicyclepress.com/BQPBPEquipsurvey.pdf
Tim McNamara
<b0046018-b5e0-435f...@k13g2000hse.googlegroups.com>,
frkr...@gmail.com wrote:
> On Mar 15, 7:24 pm, Andre Jute <fiul...@yahoo.com> wrote yet another
> of his ever-expanding tirades of insults. In the interest of
> brevity, I'll respond to only a few points:
A good idea.
> > The point about the best and most expensive of those dynohub lights
> > is that none of them put out enough light. Let me repeat that:
> > there is no dynohub light that puts out enough light for any but
> > the most undemanding circumstances, like riding on the sidewalk or
> > perhaps on quiet, lit streets
I see you suffer from the same misunderstanding as another poster here.
> Absolutely false. Nearly half the American RUSA contingent in the
> last Paris-Brest-Paris competition used dynamo lights. And a post-
> ride survey showed they were more satisfied with their lights than
> the battery-powered group. See
> http://www.vintagebicyclepress.com/BQPBPEquipsurvey.pdf
>
> I think most would agree Paris-Brest-Paris is a bit more extreme than
> sidewalk riding.
It is, and Andre is just plain wrong yet again.
Dan O
>
> With one exception, I've never been in a place where a legally lit
> cyclist is not sufficiently conspicuous. I've satisfied myself
> literally hundreds of times that I'm even more visible at night than I
> am in daytime.
WTF?!?
carl...@comcast.net
wrote:
Dear Dan,
I expect that Frank's point is that at night even a small light is
noticeable at a much greater distance than a larger ordinary object in
daylight.
Your computer screen probably has a small green power light that you
scarcely notice when the room is lit. Turn the lights off and notice
how visible even that tiny light becomes.
The contrast between a light and the dark background catches the eye.
Cheers,
Carl Fogel
(PeteCresswell)
>And that's fine. I prefer generator lights because there is no hassle
>about tending or replacing or charging or remembering batteries. My
>bike is always ready to ride at night, at a moment's notice. I also
>find the reliability is significantly higher in other ways.
What are you currently using for headlight/tail light?
Also, is it just tolerance for varying voltages that makes lights
electrically generator-specific?
--
PeteCresswell
frkr...@gmail.com
> Per frkry...@gmail.com:
>
> >And that's fine. I prefer generator lights because there is no hassle
> >about tending or replacing or charging or remembering batteries. My
> >bike is always ready to ride at night, at a moment's notice. I also
> >find the reliability is significantly higher in other ways.
>
> What are you currently using for headlight/tail light?
Let's see: On the two bikes I use most often at night, I've got Basta
Ellipsoid headlamps. Another bike has a Union headlamp. (I don't know
the model number - it's about 2.5" diameter, with an unusually convex
front lens.) My wife's bike has a Soubitez headlamp. There's also
the headlamp from a FER 2002 generator, and there's a tiny (maybe 1.5"
dia?) headlamp that's part of the Union "block" generator on a seldom-
used folding bike. These lights move around a bit from bike to bike,
depending on season, vacation trips, etc., and I've got others stored
in a drawer.
All these have halogen bulbs. Most are 2.4 watt, but overdriven by
virtue of having no generator taillight. One has a 3 watt bulb, but I
don't see much difference.
I like best the optics of that old Soubitez lamp, followed by the FER,
but I ride much more with the Bastas. The Union lamps are, I think,
not as good optically.
Usually I rely on LED blinky taillights powered by AA or AAA cells,
but my commuting bike also has a generator taillight. This too was
chosen for optics (improved over a previous tiny no-lens version), but
I can't tell you the brand. All bikes have various reflectors, but
nothing unusual.
> Also, is it just tolerance for varying voltages that makes lights
> electrically generator-specific?
I don't think that has much to do with it at all. Generator headlamps
are (almost always) separate units from the power source. If you use
a battery to pump 6 volts DC into a generator headlamp, it works just
fine, IME. But there are a couple uncertainties.
First, I've noticed that many of my 6V 2.4W halogen generator bulbs
have microscopic AC waveform icons stamped into the threaded base.
(Recall, bike generators are AC devices.) I don't know what could be
special about the bulbs for AC. Perhaps Andreas could tell us? But
again, I know they work with AC or DC. (Light Emitting Diodes are a
different matter, of course.)
Second uncertainty: If you decide to use a battery to power the good
optics of a generator lamp, you may be tempted to put in a more
powerful bulb. If you do, some lamps may have their plastic
reflectors damaged by the extra heat. It would depend, I suppose, on
the particular plastic they used for the reflector. I had that
problem way back when I hot rodded some non-generator handlebar-
mounted lamps. In that case, I cured it by using some silicone rubber
as thermal insulation between the bulb base and the reflector, taking
care to get the filament positioned properly at the focal point.
I've got an ancient Union generator headlamp with a metal reflector.
If I were to play around with battery power again, I'd use it.
- Frank Krygowski
Tim McNamara
<14a59561-15a4-4312...@s37g2000prg.googlegroups.com>,
Dan O <danov...@gmail.com> wrote:
WTF do you mean "WTF?!?" A bicyclist at night with a headlight and
taillight is more conspicuous than a cyclist riding during the day. Way
more contrast between a bright light and a dark background.
Andre Jute
> On Sat, 15 Mar 2008 23:19:47 -0700 (PDT), Dan O <danover...@gmail.com>
> wrote:
>
> >On Mar 15, 2:09 pm, frkry...@gmail.com wrote:
>
> >> With one exception, I've never been in a place where a legally lit
> >> cyclist is not sufficiently conspicuous. I've satisfied myself
> >> literally hundreds of times that I'm even more visible at night than I
> >> am in daytime.
>
> >WTF?!?
>
> Dear Dan,
>
> I expect that Frank's point is that at night even a small light is
> noticeable at a much greater distance than a larger ordinary object in
> daylight.
Crap. A bicyclist on a proper (Dutch city) bike is a block over six
feet high by two feet wide right out in the middle of the lane. That's
as high as a Range Rover (actually, from my bike I look *down* on
Range Rovers) and a third as wide, visible from a very long way in
daylight. A twee little light in the dark is not visible at the same
distance and, in any event, at night mere visibility is worthless: the
light must be noticed and serve as identification and warning within a
reasonable stopping distance for a car. The best Dutch and German
taillights don't do that. These notes assume total darkness. The
position gets much worse in the presence of streetlights and store
lights and infinitely worse in the presence of moving car lights. Thus
the necessity for a strong light, for substantial light cast to the
side, for a flashing light.
> Your computer screen probably has a small green power light that you
> scarcely notice when the room is lit. Turn the lights off and notice
> how visible even that tiny light becomes.
Intelligent people don't look for some twee little light to tell if
their computer is switched on. They can see the huge, throbbing screen
is shining. That is what first attracts the eyes. There should be a
lesson even for you, dear Carl, in your own example.
> The contrast between a light and the dark background catches the eye.
Of course it does, if the light is strong enough to reach the
necessary distance, and still more if the light flashes. The question
is whether the lights Andreas was defending, which are Dutch and
German taillights of the BUMM type (which is the point on which Krygo
jumped in), reach far enough for a driver to notice and if necessary
to stop from a reasonable speed, and I say that they don't, even under
the ideal condition of total darkness. In lit areas and in traffic
they will be noticed only by drivers expecting cyclists and
consciously looking out for them. Those conditions don't apply where
the majority of RBTers ride. The advice given by the Krygo-Fogel gang
is therefore dangerous to life and limb.
> Cheers,
>
> Carl Fogel
So nice to hear from you, dear Carl. But a word to wise, eh? If you
actually intend a comedy act, get a new scriptwriter. Right now you're
making ludicrous claims and being laughed out of court.
Andre Jute
Author of "The True Thoughts of Chairman Mao"
Andre Jute
> In article
> <14a59561-15a4-4312-b04a-c7612f9cf...@s37g2000prg.googlegroups.com>,
> Dan O <danover...@gmail.com> wrote:
>
> > On Mar 15, 2:09 pm, frkry...@gmail.com wrote:
>
> > > With one exception, I've never been in a place where a legally lit
> > > cyclist is not sufficiently conspicuous. I've satisfied myself
> > > literally hundreds of times that I'm even more visible at night
> > > than I am in daytime.
>
> > WTF?!?
>
> WTF do you mean "WTF?!?"
WTF do you mean WTF be means WTF?
>A bicyclist at night with a headlight and
> taillight is more conspicuous than a cyclist riding during the day. Way
> more contrast between a bright light and a dark background.
In total darkness, a condition that does not exist for most cycling
situations. This is a juvenile form of argument, Tim.
And even your basic argument is fatally undermined by the deficiency
that the light must be pretty strong to be seen at the same maximum
distance as a cyclist remains visiblein daylight
Andre Jute
Adult cycling club
Jay Beattie
It really does depend on the light system. I was driving home the
other night, and a cyclist approached from the other direction with
two, forward facing flashing LED arrays -- one on the bars and one on
the helmet. These things were blinding. I thought I had stumbled in
to an alien landing. This sort of retina burning, visible-from-
outerspace display would be far more noticeable to a car enterning
traffic from a side street (the usual culprits in a night time
colision, IMO) than a rider in daylight. This system, however, far
exceeded any legal requirement -- for any conveyance, jet, boat, train
or space ship. --- Jay Beattie.
SMS
> 3. Forget a dynopowered rear light of any kind. Even the best are
> dangerous to your health. The expensive BUMM ones are not watertight
> and the best of the rest, made by Basta (I have one they custom make
> for Gazelle but it is basically just an aesthetic variation of their
> best rear lamp) and by Spanninga (their Ultra; I have that one as
> well) are merely better waterproofed, not more illuminative. I keep
> them on my bikes simply because they came with the bikes. Even the
> best of the dynodriven rear lights are little glimmers that you can
> barely see across the street. None of the dyno-driven rear lights
> flash, because it is streng verboten to have flashing lights in
> Germany and The Netherlands, their prime markets.
Good advice. I had some long discussions with Dutch manufacturers at
the show about their products (and their lack of exporting to the
U.S.), and especially about lighting. I was very suprised to see some
new higher end Dutch commuter bikes with no dynamos at all, hub or
rim. They told me that there is a trend even in the Netherlands toward
battery powered lights at the mid-range for two reasons. First, the
rim dynamos are too unreliable in terms of wiring and in terms of
being damaged when the bicycles are parked, but the hub dynamos are
too expensive except at the very high end. Second, the lights are only
useful as "being seen" lamps at the relatively slow speeds on the
cycle paths.
> 4. Get a battery rear light. If you're rich, get a Dinotte rear light
> (ask Jay; he has one), if not a Cateye TL-LD1100, which is pricey
> enough. There is only one other taillight that is good enough for your
> life and that's the Trek Disco Inferno, which is no longer made. The
> Dinotte and the Cateye 1100 are *bright*, they cast very substantial
> light to the sides as well as the rear, and they flash. Those are the
> minimum requirements for good taillights, and they are the only ones
> who truly meet them. The Cateye 1100 is bright enough to be seen in
> bright sunlight; I use it as a daylight running lamp. It is supposed
> to last 200 hours on a set of 2 AA batteries; I don't know how long
> the batteries last in hours because I use rechargeables and swap them
> out every three or four months or so.
>
Other than folding bicycles, there were probably more new attempts at
LED lights than any other product at the show, including several LED
brake lights and turn signal lights, including some with wireless
transmitters from a switch on the bars But in all the show, the best
rear light remained the CatEye 1100. DiNotte was not at the show.
There actually is a decent tail light from Blackburn (in terms of
brightness and angle of view) but it suffers from using AAA batteries.
> 7. Or you might want to considering overvolting a single halogen lamp:
> you get far more light and you won't blow a Philips MR16 or MR11
> longlife unit --anyway, what do you care if you reduce a 3000 mtbf
> lamp to 1500 hours of life if you get nearly twice as much light? The
> trick is that you must be able to get them in the 6V versions to work
> with your dynohub, and the 6V MR16 or MR11 are not easy to find, at
> least not where I live.
Yeah, the poor man's HID system! Have you tried a 5W 6V MR16 on a 3W
dynohub?
"http://www.bulbtown.com/5W_6V_MR16_WITH_LENSE_GX5_3_BASE_p/43243.htm"
> 8. Or, in LEDs, you can fit as many low consumption LEDs as you can
> power. Each LED drops y volts, so the total must add up to what your
> dynohub produces or must be regulated. You might want to look into
> buckpucks to get the voltage right. Frankly, I wouldn't mess with LEDs
> unless I could get the latest and the best, together with some means
> of focusing the light correctly, and were also willing to sacrifice an
> existing set of lights with hefty, preferably cast ali, shells for
> cooling the LEDs. I looked into LEDs and decided that BUMM's Fly IQ
> (at the expensive end of their range, which is generally overpriced)
> would probably in the end cost less than messing around trying to make
> my own.
I was surprised to see so few LED based dynamo lights at the show,
because I incorrectly assumed that you could drive something like a
3W Cree LED from a dynamo hub. You can't. Most of the dynamo LED based
lights were three lower wattage LEDs, and not focused or collimated
all that well. Plus no manufacturer is apparantly willing to spend big
bucks on the bins of the Cree LED that are the most efficient.
The best LED headlamp appears to still be the SolidLight's 1203D.
Interestingly, tthey don't mention the LED type anywhere, nor the
wattage.
> 9. If you're cheap or poor, consider this. Plenty of RBT dickswingers
> will now weight in with how fabulous their BUMM Fly IQ is; I have one
> too and it is a good light. However. A couple of halogen 2.4W lamps --
> because that is what I had at the time of the test; 2x 3W lights would
> do better still -- made as much light as the Fly at any speed over a
> crawl and could be better arranged because the two lamps had different
> spreads.
There is a mistaken belief by many that an LED based light is
necessarily more efficient than a filament based lamp. This is untrue
for higher power lights. The measures taken to dissipate the heat from
a high power LED lamp are quite incredible. Plus an LED llamp is much
harder to lens properly. There are advantages, such as the longer life
of the LED compared to the filament based bulb, especially in a harsh
environment. You keep hearing how LEDs will soon catch up with HID in
terms of efficiency, and this may happen but it's not going to be
cheap. The LED manufacturers already charge a big premium for the
their most efficient product bins, and you see Cree based lights
specifying which bin the LEDs come from.
> 10. Lights are the last bicycle frontier. We hear a lot of talk from
> the technofreakies about how dynamo lights are now so much better than
> they were. But better isn't automatically good enough. The best dyno
> front light is still only nearly as good as a 10W MR11 battery light
> -- whereas I don't feel comfortable on any aspect of lighting (being
> seen, having my space respected, seeing) with anything less than about
> 25W divided between two lamps. YMMV, of course.
Personally I find MR11 based lamps a waste, because the larger
reflector of the MR16 is much more efficient. In fact the sealed beam
12 volt lamps are becoming one of my favorite halogen lamps because of
the large reflector, light weight, and the lack of a need to build any
funky enclosure.
> 11. In summary: I recommend the Cateye TL-LD1100 battery rear light,
> and two cheap BUMM halogen lights driven off the dynamo at the front
> with a homemade switch, supplemented in case of regular commuting or
> any strenuous riding circumstances by a rechargeable battery front
> light set .
Good advice. I'm finding that for many short, slow rides to the store
that the dynamo lights are sufficient. It's for commuting, especially
at relatively high speed, that the higher power lights are necessary
for optimal safety.
> 13. Good strong lights are useful in daylight too. The flashing Cateye
> 1100 persuades a lot of people to slow behind me and to give me a
> wider berth than they did before I fitted that light.
Try a Flash Flag. See "http://www.flashback.ca/bicycle.html". You can
probably make something similar. I use these on most of our fleet of
bikes, but I'm working on something better. I don't like the lack of a
good breakaway mechanism. Some sort of replaceable, cheap mechanism is
needed. I was hoping to see something similar to the Flash Flag at the
bike show, but there was nothing.
(PeteCresswell)
>Flash Flag. See "http://www.flashback.ca/bicycle.html".
Somebody marketed something like that back in the late
seventies/early eighties called "The Sting".
AFIK, it didn't go anywhere.
--
PeteCresswell
Andre Jute
I couldn't agree with you more, Jay. A blinding light is as
counterproductive as an inadequate light. Bicycle lights, front and
rear, should be adequate to the task but not a hazard to other road
users. But on RBT it must often seem to you that you are the last
moderate here; I keep stumbling into entrenched prejudice that leads
to vicious responses on helmets and lights, not to mention motor
pacing... -- Andre Jute
SMS
Too bad. I find the Flash Flag to be very effective in having
motorists give me more room. Whether it's because they see me better,
or because they just don't want to risk scratching their vehicle, it's
a simple device that achieves its purpose, including in the daytime
where only a few LED flashers are bright enough to be effective.
SMS
wrote:
> "(PeteCresswell)" <x...@y.invalid> wrote:
> > Per Hank:
> >>I was a liberal arts major, so I bought a Lumotec IQ Fly , crimped the
> >>spade connectors, and plugged it into my SON. Piece of cake.
>
> > Having said all that.... Thanks for the terminology. Googling
> > "Lumotec" led right to Peter White's page dedicated to generator
> > lighting.
> >http://www.peterwhitecycles.com/schmidt-headlights.asp
>
> Bike generators match very well to light emitting
> diodes.
The problem wiht LEDs is that the AC, non-regulated voltage out of the
dynamo isn't well suited to driving LEDs without some extra
electronics to convert the AC to DC and to keep the current and
voltage constant. To achieve this at low cost and at high efficiency
is not yet possible. This is why the few good dynamo LED lights are so
expensive.
A filament bulb requires only some over-voltage protection, doesn't
care about AC or DC, and lends itself to more efficient optics.
I wish that there would be some higher power dynamos, even at the
expense of more drag and more weight. All that's needed is enough
power to keep a 3W Cree LED, battery powered light, charged. A 4 cell
Cree LED light that automatically switched between two sets of two
cells (operating on one while charging the other from a dynamo) would
be one solution that would be possible with a slightly higher power
dynamo, and would give the best of both worlds. But you're talking
about a $100 headlight by the time it's at the retail level in
volume.
A Muzi
>>>> I was a liberal arts major, so I bought a Lumotec IQ Fly , crimped the
>>>> spade connectors, and plugged it into my SON. Piece of cake.
>> "(PeteCresswell)" <x...@y.invalid> wrote:
>>> Having said all that.... Thanks for the terminology. Googling
>>> "Lumotec" led right to Peter White's page dedicated to generator
>>> lighting.
>>> http://www.peterwhitecycles.com/schmidt-headlights.asp
> bob prohaska's usenet account <b...@www.zefox.net> wrote:
>> Bike generators match very well to light emitting
>> diodes.
SMS wrote:
> The problem wiht LEDs is that the AC, non-regulated voltage out of the
> dynamo isn't well suited to driving LEDs without some extra
> electronics to convert the AC to DC and to keep the current and
> voltage constant. To achieve this at low cost and at high efficiency
> is not yet possible. This is why the few good dynamo LED lights are so
> expensive.
>
> A filament bulb requires only some over-voltage protection, doesn't
> care about AC or DC, and lends itself to more efficient optics.
>
> I wish that there would be some higher power dynamos, even at the
> expense of more drag and more weight. All that's needed is enough
> power to keep a 3W Cree LED, battery powered light, charged. A 4 cell
> Cree LED light that automatically switched between two sets of two
> cells (operating on one while charging the other from a dynamo) would
> be one solution that would be possible with a slightly higher power
> dynamo, and would give the best of both worlds. But you're talking
> about a $100 headlight by the time it's at the retail level in
> volume.
I thought I might throw out my bikes and just sit down and cry because
the world is imperfect. Instead, I just ride with normal dynamo lights.
Installed once and never given a moment's thought since.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
Tim McNamara
<8613b92c-0122-4922...@s8g2000prg.googlegroups.com>,
Jay Beattie <jbea...@lindsayhart.com> wrote:
> On Mar 16, 10:07 am, Andre Jute <fiul...@yahoo.com> wrote:
> > On Mar 16, 4:11 pm, Tim McNamara <tim...@bitstream.net> wrote:
> >
> > > In article
> > > <14a59561-15a4-4312-b04a-c7612f9cf...@s37g2000prg.googlegroups.com
> > > >, Dan O <danover...@gmail.com> wrote:
> >
> > > > On Mar 15, 2:09 pm, frkry...@gmail.com wrote:
> >
> > > > > With one exception, I've never been in a place where a
> > > > > legally lit cyclist is not sufficiently conspicuous. I've
> > > > > satisfied myself literally hundreds of times that I'm even
> > > > > more visible at night than I am in daytime.
> >
> > > > WTF?!?
> >
> > > WTF do you mean "WTF?!?"
> >
> > WTF do you mean WTF be means WTF?
> >
> > >A bicyclist at night with a headlight and
> > > taillight is more conspicuous than a cyclist riding during the
> > > day. Way more contrast between a bright light and a dark
> > > background.
> >
> > In total darkness, a condition that does not exist for most cycling
> > situations. This is a juvenile form of argument, Tim.
> >
> > And even your basic argument is fatally undermined by the
> > deficiency that the light must be pretty strong to be seen at the
> > same maximum distance as a cyclist remains visiblein daylight
Try testing this in reality rather than in your imagination. The
reverse of your position is true.
> It really does depend on the light system. I was driving home the
> other night, and a cyclist approached from the other direction with
> two, forward facing flashing LED arrays -- one on the bars and one on
> the helmet. These things were blinding. I thought I had stumbled in
> to an alien landing. This sort of retina burning, visible-from-
> outerspace display would be far more noticeable to a car enterning
> traffic from a side street (the usual culprits in a night time
> colision, IMO) than a rider in daylight. This system, however, far
> exceeded any legal requirement -- for any conveyance, jet, boat,
> train or space ship. --- Jay Beattie.
Which some participants in these discussions would still find to be
deficient lighting in some way.
Andre Jute
> On Mar 14, 9:05 pm, Andre Jute <fiul...@yahoo.com> wrote:
>
> > 3. Forget a dynopowered rear light of any kind. Even the best are
> > dangerous to your health. The expensive BUMM ones are not watertight
> > and the best of the rest, made by Basta (I have one they custom make
> > for Gazelle but it is basically just an aesthetic variation of their
> > best rear lamp) and by Spanninga (their Ultra; I have that one as
> > well) are merely better waterproofed, not more illuminative. I keep
> > them on my bikes simply because they came with the bikes. Even the
> > best of the dynodriven rear lights are little glimmers that you can
> > barely see across the street. None of the dyno-driven rear lights
> > flash, because it is streng verboten to have flashing lights in
> > Germany and The Netherlands, their prime markets.
>
> Good advice. I had some long discussions with Dutch manufacturers at
> the show about their products (and their lack of exporting to the
> U.S.), and especially about lighting. I was very suprised to see some
> new higher end Dutch commuter bikes with no dynamos at all, hub or
> rim. They told me that there is a trend even in the Netherlands toward
> battery powered lights at the mid-range for two reasons. First, the
> rim dynamos are too unreliable in terms of wiring and in terms of
> being damaged when the bicycles are parked, but the hub dynamos are
> too expensive except at the very high end. Second, the lights are only
> useful as "being seen" lamps at the relatively slow speeds on the
> cycle paths.
That's a retrograde step. Both my Dutch bicycles have dynamo-driven
front lights and battery rear lights, a very common arrangement at the
high end, the reason being the problem (aesthetics, reliability) of
wiring a dynamo-driven light at the back. But conceptually, once you
accept that the dynamo lights are being-seen lights, or seeing lights
only in undemanding situations, and that for any demanding use
(including by people with a true value of their own lives) such lights
must be supplemented by battery lights, it makes sense to have dyno-
drive lights front *and* back as backups in case the batteries run
out. I'm sure that if they put their minds to it the bike makers or
lamp makers could solve the problem right pronto. (However, I notice
that Shimano is no longer supplying either the front lamp they used to
list, nor the switch they used to list for dynohubs; I wonder if the
glow has gone off the dynohub market for Shimano.)
> > 4. Get a battery rear light. If you're rich, get a Dinotte rear light
> > (ask Jay; he has one), if not a Cateye TL-LD1100, which is pricey
> > enough. There is only one other taillight that is good enough for your
> > life and that's the Trek Disco Inferno, which is no longer made. The
> > Dinotte and the Cateye 1100 are *bright*, they cast very substantial
> > light to the sides as well as the rear, and they flash. Those are the
> > minimum requirements for good taillights, and they are the only ones
> > who truly meet them. The Cateye 1100 is bright enough to be seen in
> > bright sunlight; I use it as a daylight running lamp. It is supposed
> > to last 200 hours on a set of 2 AA batteries; I don't know how long
> > the batteries last in hours because I use rechargeables and swap them
> > out every three or four months or so.
>
> Other than folding bicycles, there were probably more new attempts at
> LED lights than any other product at the show, including several LED
> brake lights and turn signal lights, including some with wireless
> transmitters from a switch on the bars But in all the show, the best
> rear light remained the CatEye 1100. DiNotte was not at the show.
>
> There actually is a decent tail light from Blackburn (in terms of
> brightness and angle of view) but it suffers from using AAA batteries.
That makes all of *three* generally available good tail lights... A
shameful situation, I think.
There's also a rather ugly front light from Blackburn that I might us
as a front flasher. But first I want to look into making something
like the BUMM Fly IQ flash, so it can run off the dynohub and be there
in cast I want to use it in steady mode. I'm also wondering if I can
make the Cateye 1100 work off the dynohub for the rear.
> > 7. Or you might want to considering overvolting a single halogen lamp:
> > you get far more light and you won't blow a Philips MR16 or MR11
> > longlife unit --anyway, what do you care if you reduce a 3000 mtbf
> > lamp to 1500 hours of life if you get nearly twice as much light? The
> > trick is that you must be able to get them in the 6V versions to work
> > with your dynohub, and the 6V MR16 or MR11 are not easy to find, at
> > least not where I live.
>
> Yeah, the poor man's HID system! Have you tried a 5W 6V MR16 on a 3W
> dynohub?
>
> "http://www.bulbtown.com/5W_6V_MR16_WITH_LENSE_GX5_3_BASE_p/43243.htm"
Thanks for the link. They don't deliver to Europe though. The reason I
haven't tried 6V MR16 is that I can't find any locally or deliverable
for a reasonable price, and in fact have several perfectly good (of
their kind, for their purpose) 6V dyno front lights made by Basta,
Spanninga and BUMM.
> > 8. Or, in LEDs, you can fit as many low consumption LEDs as you can
> > power. Each LED drops y volts, so the total must add up to what your
> > dynohub produces or must be regulated. You might want to look into
> > buckpucks to get the voltage right. Frankly, I wouldn't mess with LEDs
> > unless I could get the latest and the best, together with some means
> > of focusing the light correctly, and were also willing to sacrifice an
> > existing set of lights with hefty, preferably cast ali, shells for
> > cooling the LEDs. I looked into LEDs and decided that BUMM's Fly IQ
> > (at the expensive end of their range, which is generally overpriced)
> > would probably in the end cost less than messing around trying to make
> > my own.
>
> I was surprised to see so few LED based dynamo lights at the show,
> because I incorrectly assumed that you could drive something like a
> 3W Cree LED from a dynamo hub. You can't.
No free lunch? I assume it consumes too much current.
> Most of the dynamo LED based
> lights were three lower wattage LEDs, and not focused or collimated
> all that well. Plus no manufacturer is apparantly willing to spend big
> bucks on the bins of the Cree LED that are the most efficient.
>
> The best LED headlamp appears to still be the SolidLight's 1203D.
That's *very* expensive, Steven. I looked into the SolidLight and was
tempted, but it will be outmoded before I've even run it in, and then
my money will be wasted.
> Interestingly, tthey don't mention the LED type anywhere, nor the
Luxeon 3W from a select bin, I imagine.
I looked into those garden lighting decorator types of sealed beams
you recommend but again it was a supply problem.
> > 11. In summary: I recommend the Cateye TL-LD1100 battery rear light,
> > and two cheap BUMM halogen lights driven off the dynamo at the front
> > with a homemade switch, supplemented in case of regular commuting or
> > any strenuous riding circumstances by a rechargeable battery front
> > light set .
>
> Good advice. I'm finding that for many short, slow rides to the store
> that the dynamo lights are sufficient. It's for commuting, especially
> at relatively high speed, that the higher power lights are necessary
> for optimal safety.
I really hoped that a hub dynamo would be so much better than sidewall
dynamos but it is not so: the light output in my kinds of mild use is
no higher. The truth is that a hub dynamo with even the best lamps
designed for it doesn't make adequate light for any of my nighttime
rides -- I might turn from the shop across the unlit graveyard, or
from a garage which sometimes has a veteran car into the rough tracks
on the estate of a friend, and in both places the spread of light
from dynohub lights, and the difficulty of starting up again after you
stop, make the ride into an unnecessarily stressful adventure.
> > 13. Good strong lights are useful in daylight too. The flashing Cateye
> > 1100 persuades a lot of people to slow behind me and to give me a
> > wider berth than they did before I fitted that light.
>
> Try a Flash Flag. See "http://www.flashback.ca/bicycle.html". You can
> probably make something similar. I use these on most of our fleet of
> bikes, but I'm working on something better. I don't like the lack of a
> good breakaway mechanism. Some sort of replaceable, cheap mechanism is
> needed. I was hoping to see something similar to the Flash Flag at the
> bike show, but there was nothing.
I think the Cateye 1100 at last does the business, even in daylight;
if Cateye's next model is as much of an improvement over the 1100 as
the 1100 was over the 1000, I will buy that one too. A guy with a 1000
was passing in the winter here at dusk, very poor visibility. He
immediately noticed my 1100 was stronger. We fitted fresh batteries
from my bulk pack, parked the bikes on the hard shoulder with the
lights flashing and walked back. The 1100 was visible for more than an
additional 150 paces, at which point a curve in the road intervened.
This fellow, a Brit, had thought the 1000 a revelation, very good
indeed on cycling hols he takes all over the world every few weeks
when he can get a cheap flight, but he said he would buy the 1100 next
time he was in a shop. He was the one that pointed out to me that the
key is that the bike lights should still be noticeable under street
lights and in traffic; that a test in pitch dark is an engineering
test but useless as a utility test. My Spanninga Ultra, highly thought
of in The Netherlands, recommended in a Fietserbond test, was on the
same bike as the Cateye 1100 and didn't pass our impromptu test.
Andre Jute
I wouldn't want to be on even a cager's conscience
SMS
> That's a retrograde step. Both my Dutch bicycles have dynamo-driven
> front lights and battery rear lights, a very common arrangement at the
> high end, the reason being the problem (aesthetics, reliability) of
> wiring a dynamo-driven light at the back. But conceptually, once you
> accept that the dynamo lights are being-seen lights, or seeing lights
> only in undemanding situations, and that for any demanding use
> (including by people with a true value of their own lives) such lights
> must be supplemented by battery lights, it makes sense to have dyno-
> drive lights front *and* back as backups in case the batteries run
> out. I'm sure that if they put their minds to it the bike makers or
> lamp makers could solve the problem right pronto. (However, I notice
> that Shimano is no longer supplying either the front lamp they used to
> list, nor the switch they used to list for dynohubs; I wonder if the
> glow has gone off the dynohub market for Shimano.)
I was talking to someone from Sturmey Archer at Taipei Cycle a few
days ago, and I was looking at their combination drum brake/dynamo. I
asked if they were going to do a dynamo-only, having no interest in
drum brakes, but he said that there was just not enough demand, and
not enough money in it. While the dynohubs sold after-market fetch
high prices, the bicycle manufacturers pay probably 1/10th of the
retail price for a dynamo, and even in Europe the dynamos are losing
favor. Ironically it's in the U.S. where there is some renewed
interest in dynamos from the likes of the Breezer bikes, and a few
other commuter bikes. Dahon offers the Biologic Joule hub, apparently
made only for them.
I think that one of the reasons that the dynamo lights are losing
favor is because LEDs aren't well suited for making cheap headlights
for dynamos, but are very well suited for cheap battery lights. Still,
the good LED bicycle lights, using the best binned LEDs, are not cheap
enough for the mass market. There's a limited demand for DiNotte
lights at those prices. DiNotte wants to buy one of my domain names,
but I need to wait until they sell enough lights to meet my price!
I was very impressed with one company's Cree LED bicycle light and
flashlight. They did very good optics for the bicycle light, but in
fact they tried too hard! One of the big advantages of a standard Cree
LED flashlight is that it _does illuminate off to the sides, and not
just directly in front of the bicycle. Contrary to what some people
believe, it's not illumuniting the sky!
The highlight of my trip was meeting Joe Breeze as he rode in from his
hotel on a Dahon, lent to him by Josh DaHon. Of course I made an idiot
out of myself before I realized who he was! The mindset was the same
anyway, stay out by the main train station and MRT in a two star
hotel, where it's much more interesting, as well as much less
expensive than the 5 star hotels where most of the bicycle execs stay.
He asked if my hotel had a window, and said that his window looked out
on nothing but the window of the room across.
Well gotta go pack for the trip back.
Jay Beattie
I would find it deficient lighting if I were riding the bike. I don't
like riding with front flashing lights. I mean really, it's a road
not a disco.-- Jay Beattie.
SMS
> That makes all of *three* generally available good tail lights... A
> shameful situation, I think.
>
I saw one more at an LBS the other day but I forgot the manufacturer
and model. I need to go back to that shop to find out.
I don't know if shameful is the right word. You basically have a
product (bicycle lights) where the market for a high end product at a
high price is very small, and where most consumers have no idea of the
difference between a $3 flasher and a $30 CatEye TL-DL1100.
If there was a well written standard requirement for bicycle lighting,
both front and rear, the situation would change. The problem is that
the existing standards are decades old, and are based not on what
would provide an adequate level of safety, but on what can be powered
from a dynamo (at least in parts of Europe).
As with many products, the responsibility is on the consumer to
understand that the government isn't going to protect them, and that
they need to buy the proper products. The problem is more that some
people believe that the lame minimum standards are actually
sufficient. You're pretty hard on Frank, but he's no different than
the typical non-scientist, non-engineer consumer that has no knowledge
of this type of product, and has no desire to spend time becoming
knowledgable. The thing is that it shouldn't be necessary to have to
become an expert on every product you buy!
> I really hoped that a hub dynamo would be so much better than sidewall
> dynamos but it is not so: the light output in my kinds of mild use is
> no higher. The truth is that a hub dynamo with even the best lamps
> designed for it doesn't make adequate light for any of my nighttime
> rides
They are often okay on known routes, or well lit streets, where you
won't encounter anything like you mentioned. There is only so much
power you can get out of a 3 watt dynamo, and efforts to convert the
native voltage and current into something more useful for LEDs results
in unacceptable losses in the conversion process.
SMS
> The highlight of my trip was meeting Joe Breeze as he rode in from his
> hotel on a Dahon, lent to him by Josh DaHon.
Oops, it's Josh Hon, not DaHon. I was talking to the wife of DaHon's
founder in the DaHon booth, about the whole name thing. She said they
were sure they would have won the lawsuit but at the time they didn't
want to spend money fighting the Hon office furniture company.
Peter Cole
> What light bulbs/LED emitters are you powering with your
> Sturmey-Archer Dynohub?
>
> Front? Back?
>
> I did the thing with the bridge rectifier to convert it's output
> to DC - figuring I'd drive some LED emitters to get max light.
>
> But I'm having problems with the voltage regulator part. I get
> the circuit tuned to put out, say, 1.5 volts with 6 volts coming
> in from a 4-battery test source and then when I put another
> battery in series, the output voltage rises to 2.something.
>
> Probably something dumb I'm doing in the regulator, and I expect
> to do it right eventually.
>
> But it got me to wondering how voltage-tolerant light bulbs and
> LEDs are. My assumption going into this has been "not very",
> but I don't have much to base that on.
>
> Am I doing the voltage regulation piece in vain? Do I really
> need regulation? When I hang a voltmeter on the DC output it
> varies from 3 volts at a walking pace to about 20 volts on a
> downhill.
>
> So, bottom line, who is using what without toasting a lot of
> bulbs yet getting plenty light?
The combined characteristics of LEDs and dynamos make regulation difficult.
Dynamos generate a voltage proportional to speed by rotating a permanent
magnet in a coil. This eliminates the simplest method of regulation
(varying the field strength).
Incandescent bulbs increase resistance with power (filament
temperature). This makes them somewhat self-regulating. LEDs, on the
other hand, decrease resistance with temperature, making them somewhat
self-unregulating (prone to thermal runaway). LED characteristics are
even less favorable to regulation in that the resistance is extremely
non-linear, while filaments are approximately linear.
The two common ways to regulate are: putting a varying load in series
with the lamp load or switching the load (rapidly) in and out of the
circuit. The latter approach is significantly complicated by the
inductance of the dynamo, currents in inductors don't want to be
switched -- that's why dimmers on compact florescent lamps are not common.
These characteristics leave only the addition of a series dynamic load
as a simple regulator. Given the non-linearity of LED response and
thermal drifts, the regulator must sense current at relatively low
voltages. Unfortunately, even if done well, this approach results in
converting excess power into heat, rather than additional light. It's a
bit simplistic, but fairly accurate to think of a LED as a current
device and a dynamo as a voltage device and the problems that arise as
being from this fundamental mismatch.
An ideal way to match these two devices would be to have a lamp with
multiple LEDs (in series) and electronics that would sense the current
and keep it within limits by switching shunts across the individual
elements. Of course this complicates both the electronics and the optics.
The simple, "brute force" way would be to stack enough LEDs to match the
designed voltage range of the dynamo, spec'ing enough power handling in
the LEDs to handle peak dynamo output. This approach would take
advantage of the good efficiency and color of under-driven LEDs.
Practically speaking, if you used 3, 3W power LEDs (like the Cree),
you'd probably be able to handle the full output of the SA dynamo, but
the LEDs wouldn't start lighting until the dynamo was outputting 7.5V or
so. The inefficient approach would be to just use a single power LED and
pick an appropriate "ballast" resistor. You might be able to wire 2 or
more LEDs in parallel with separate ballast resistors in each "leg",
this would give you more light at low speeds, but you'd have to watch
out for current hogging and thermal runaway.
The ideal would be to simply have a single LED that was rated for the
full power output of the dynamo matched with a dynamo wound for the LED
characteristics. I'm not sure how close you can get to that with
available components.
frkr...@gmail.com
> On Mar 16, 4:24 pm, Andre Jute <fiul...@yahoo.com> wrote:
>
> > That makes all of *three* generally available good tail lights... A
> > shameful situation, I think.
>
>
> product (bicycle lights) where the market for a high end product at a
> high price is very small, and where most consumers have no idea of the
> difference between a $3 flasher and a $30 CatEye TL-DL1100.
>
> If there was a well written standard requirement for bicycle lighting,
> both front and rear, the situation would change. The problem is that
> the existing standards are decades old, and are based not on what
> would provide an adequate level of safety, but on what can be powered
> from a dynamo (at least in parts of Europe).
Sorry, but it's pretty obvious that taillight standards, where they
exist, are not set by dynamo limitations. They are set by judgment
about adequate safety.
To explain: The typical bike generator is a 3 Watt unit. Typical
bulbs are chosen for 2.4 W headlights and 0.6 W taillights.
But first, if it were felt necessary to send more power to the rear,
that balance could have easily been changed. Authorities could have
called for 2W front, 1W rear. But they saw no need.
Second, 6 watt generators have been available (although not common)
for many years. If there were some rash of rear-end collisions in
countries where generators are dominant, the governments could have
simply mandated 6 W generators on all new bikes, with up to 3.6 W
devoted to taillights. But again, the road safety professionals in
those countries saw no such need.
Third, the invention (in the 1980s) of LED taillights was another
opportunity to increase brightness greatly, with zero technical
difficulty. VistaLight engineers, for example, could have simply
added more LEDs and reduced their battery life from, oh, 200 hours to
a still superb 150 hours. Obviously, they saw no need.
And the assertion by SMS and Jute that most taillights are inadequate
is typical of their unproven, yet dogmatic assertions. Scharf and I
have discussed this for years, and while he's stated that cyclists
should be using high-powered disaster-warning strobe lights, he has
not yet produced any evidence that legally lit cyclists are being mown
down at night. (Yes, the per-mile risk of fatality at night is
apparently higher, but indications are that the causes are a mix of
drunk cycling and zero lights or reflectors, rather than lights and
reflectors that are present but inadequate.)
In fact, all but two (IIRC) US states, and many other countries, have
no government requirements for taillights. That is, they judge
reflectors alone to be adequate in the rear. I do advocate taillights
for bikes, but I think it's safe to say that all modern taillights are
much more functional than mere reflectors - that is, they achieve the
level of conspicuity that most safety professionals have deemed
adequate.
> As with many products, the responsibility is on the consumer to
> understand that the government isn't going to protect them, and that
> they need to buy the proper products. The problem is more that some
> people believe that the lame minimum standards are actually
> sufficient.
A Scharfian proclamation of "lame" doesn't prove the standards are
insufficient!
In the past, I've cited papers testing the conspicuity of various
lights and reflectors for pedestrian and bicycle use. I won't dig
them out again now, since work is calling me, but IIRC, a minimal
reflector was visible to a motorist at something like a quarter mile,
and actively noticed by the motorist in _plenty_ of time for safe
passing.
And I think those of us who drive cars can verify this based on our
own experiences. How many times have you noticed simple LED blinky
taillights from 1/4 mile away? For me, it's countless times, in all
environments.
And how many times have you had to swerve your car at the last second
because you barely noticed you were approaching a legally lit cyclist
at night? For me, it's never. Scharf has mocked this in the past,
but really - if there's no evidence that legally lit cyclists are
being mown down or barely missed, then there's no evidence of a
problem.
The fact is, a bicyclist does NOT need extreme equipment to ride
safely at night. There will always be at least two groups who
disagree - the "cycling is dangerous!!!!" crew, and those who hope
(or, like Scharf, once hoped) to make money by selling expensive
lighting equipment.
But if these folks provide no evidence, they deserve no audience.
- Frank Krygowski
Tosspot
That would very much depend on what the cyclist was wearing and the
background he's viewed against. A BUMM standlight is easily visible
from more than a kilometer on a partially light cycle path at night, the
same is true in the day of course, but you have to find the cyclist first.
Sort of related, this is why I like flashing rear lights, because on the
road, at night, your rear light is just another one in a sea of red
lights, and the other ones usually come in pairs.
Tosspot
> On Mar 16, 9:00 pm, SMS <scharf.ste...@gmail.com> wrote:
<snip>
There's also a rather ugly front light from Blackburn that I might us
> as a front flasher. But first I want to look into making something
> like the BUMM Fly IQ flash, so it can run off the dynohub and be there
> in cast I want to use it in steady mode. I'm also wondering if I can
> make the Cateye 1100 work off the dynohub for the rear.
Are you suggesting I shouldn't be running my IQ Fly off of my dynohub or
am I misunderstanding something here?
<snip>
Andre Jute
Our tests were not on cyclepaths but on a busy road with a visually
busy background. We tested a common dayglow vest and a black jacket.
The black jacket in daylight didn't lose by much because a bicyclist
is actually quite visible simply as a moving block. Most cyclist round
here are also good about bright clothing.
> Sort of related, this is why I like flashing rear lights, because on the
> road, at night, your rear light is just another one in a sea of red
> lights, and the other ones usually come in pairs.
The flashing light wins hands-down in all situations. I suspect that
in another couple of generations commonly available flashing lights
might become too strong, as Jay Beattie has pointed out, and then
we'll be able to make a test to discover the optimum (and no doubt
Krygo and Andreas Oehler will complain that we're blinding poor
innocent motorists). At present I like my Cateye 1100 as the most
reasonably priced rear lamp that offers a measure of daylight safety
as sell.
I might add that I view the growth of LED rear lights in cars with
dismay; until quite recently a LED rear light served to identify a
bike, and I haven't given up on the dream of educating motorists to
take *more* care around a cyclist than around a car.
Andre Jute
Andre Jute
Misunderstanding. I use a flashing Cateye 1100 at the rear for a
daylight running lamp. I want a flashing light at the front for a
daylight running lamp. It would be great to be able to run it off the
dynohub but no such lamp is available at a reasonable price. (The
SolidLights 1203D is a dynohub LED light with a flashing mode but it
is very expensive.) So I thought I might add a little DIY electronics
and make my Fly IQ flash...
Andre Jute
From Weihnachts Oratorium to the Ride of the Valkyries
SMS
> An ideal way to match these two devices would be to have a lamp with
> multiple LEDs (in series) and electronics that would sense the current
> and keep it within limits by switching shunts across the individual
> elements. Of course this complicates both the electronics and the optics.
This is what I saw at the bike show. The LED dynamo lamps used three
LEDs, but it wasn't automatic switching, you had to do it manually.
The problem is that mass-market headlights can't cost $50, and can't
waste much of the limited dynamo power in powering the electronics.
Manual switching is crude, but it works.
> The ideal would be to simply have a single LED that was rated for the
> full power output of the dynamo matched with a dynamo wound for the LED
> characteristics. I'm not sure how close you can get to that with
> available components.
You really just need a buck/boost DC to DC converter after converting
the output of the dynamo to DC. The problem is the losses you incur in
the conversion are unacceptable, though even with an incandescent bulb
the over-voltage limiting results in losses.
The bottom line is that you're better off with halogen bulbs for dynamo
systems, unless you're willing to spend a lot of money on something like
the SolidLight.
SMS
> I thought I might throw out my bikes and just sit down and cry because
> the world is imperfect. Instead, I just ride with normal dynamo lights.
> Installed once and never given a moment's thought since.
Yes, all the effort to avoid halogen based dynamo lights in favor of LED
based dynamo lights is really wasted effort. By the time you finish with
the electronics you need, any theoretical efficiency gain is lost, and
you've spent a lot of money for no real benefit. It isn't broken, so
there is nothing that needs fixing, at least if you're happy with the
light output from the dynamo light.
datakoll
??
Peter Cole
> Mon, 17 Mar 2008 15:20:23 GMT, Peter Cole:
>
>
>> The combined characteristics of LEDs and dynamos make regulation difficult.
>
>
>> Dynamos generate a voltage proportional to speed by rotating a permanent
>> magnet in a coil. This eliminates the simplest method of regulation
>> (varying the field strength).
>
> output. You can simply hook a LED (with a current rating higher than that
> of the generator) to the rectified generator output and you are done. If
> you want more light, connect more LEDs in series.
>
>> Incandescent bulbs increase resistance with power (filament
>> temperature). This makes them somewhat self-regulating.
>
> the generator.
>
>> LEDs, on the
>> other hand, decrease resistance with temperature, making them somewhat
>> self-unregulating (prone to thermal runaway). LED characteristics are
>> even less favorable to regulation in that the resistance is extremely
>> non-linear, while filaments are approximately linear.
>
>
> The nice thing about LEDs is: You can drive them with lower current
> without loosing much light output - even the efficiency is higher at lower
> current (just the opposite of filament bulbs).
>
>> These characteristics leave only the addition of a series dynamic load
>> as a simple regulator. Given the non-linearity of LED response and
>> thermal drifts, the regulator must sense current at relatively low
>> voltages.
>
>
>> Unfortunately, even if done well, this approach results in
>> converting excess power into heat, rather than additional light. It's a
>> bit simplistic, but fairly accurate to think of a LED as a current
>> device and a dynamo as a voltage device and the problems that arise as
>> being from this fundamental mismatch.
>
> Cree XRE 7090 LED should be run at not much more than 700mA. Modern hub
> generators (Shimano DH-3N71, SON28, SRAM i-light, Novatec EDH-1, etc.)
> will deliver not more than 600mA. The old Sturmey-Archer Dynohub delivered
> at most around 350mA.
>
>> The simple, "brute force" way would be to stack enough LEDs to match the
>> designed voltage range of the dynamo,
>
> rpm for the better hub dynamos. At 5 km/h (mounted in a 700c wheel) you
> can measure 5 Volt rms, at 50 km/h around 50 Volt rms. But short-circuit
> current nearly stays teh same independent from speed.
>
>> Practically speaking, if you used 3, 3W power LEDs (like the Cree),
>> you'd probably be able to handle the full output of the SA dynamo, but
>> the LEDs wouldn't start lighting until the dynamo was outputting 7.5V or
>> so. The inefficient approach would be to just use a single power LED and
>> pick an appropriate "ballast" resistor.
>
>
>> The ideal would be to simply have a single LED that was rated for the
>> full power output
>
>
>
> Andreas
I'm sorry, I should have put my conclusions first since you seemed to
run out of patience before you reached them.
As I said:
"The ideal would be to simply have a single LED that was rated for the
full power output of the dynamo matched with a dynamo wound for the LED
characteristics. I'm not sure how close you can get to that with
available components."
What was implied (though I obviously should have spelled it out) was
that there are two concerns for LED/dynamo lighting. First is the
capacity of the LED relative to the power of the generator. If you want
to be pedantic and insist on "current", fine. The second issue is
efficiency (obvious I thought in this application).
A SA dynohub apparently has about a 6 ohm coil. At the nominal 350ma/6V,
you're driving a bit over 2W, with 0.7W internal losses. With a 3.5V
LED, you've cut the power to the light almost in half with the same
loss, so the relative efficiency is much less.
The 350ma nominal maximum output current would be too high for safe
operation of a 1W LED, but well suited to a 3W one. Running this
unregulated off a SA would be fine, but you're only going to get ~1W to
it and the efficiency is bad.
Higher output dynohubs might be safe with unregulated 3W LEDs (barely),
but the efficiency would be bad. Again, you'd be limited to about half
of what the generator could deliver (3.5/6.0V). Another significant
factor is the rectifier losses in the (necessary) full wave bridge, that
alone will give a 70:30 power split (load:bridge). Add to all this the
increased effect of wiring losses, and when you add up all the effects
of low voltage DC lamps, the overall efficiency is bad.
An ideal approach (given available components) would be to wire the
dynohub to a rectifier/filter in the lamp and then use a switching
regulator to drive the LED.
SMS
> An ideal approach (given available components) would be to wire the
> dynohub to a rectifier/filter in the lamp and then use a switching
> regulator to drive the LED.
Actually what would be ideal is to have a DC motor/generator hub, rather
than an AC dynamo hub, but the catch is the "available components." Just
because something has been designed, or manufactured in the past, is
irrelevant.
I.e. "http://www.wipo.int/pctdb/en/wo.jsp?wo=2006016397"
Should be around 80% efficient.
I think that the no-longer-available LightSpin was putting out a
regulated 6.25 volts DC. I don't know if it was a DC generator or an
alternator that was rectified.
(PeteCresswell)
>Yes, all the effort to avoid halogen based dynamo lights in favor of LED
>based dynamo lights is really wasted effort. By the time you finish with
>the electronics you need, any theoretical efficiency gain is lost, and
>you've spent a lot of money for no real benefit. It isn't broken, so
>there is nothing that needs fixing, at least if you're happy with the
>light output from the dynamo light.
I decided to go with a halogen light bc the bulb life is supposed
to be around 100 hours and that's a *lot* of nighttime hours for
me..... AND the light only costs 20-30 bucks compared to almost a
hundred.
That being said, I'd think that the replacement aspect of halogen
bulbs could be a significant consideration for some.
Who wants tb fooling around with an itty-bitty bulb in the dark
of night out in the middle of nowhere?
OTOH, if the LED bites the big one under the same circumstances,
one *really* has a problem...
OTOOH, I guess that's a reason to keep carrying my little
Lowe's/Cree 4w flashlight...
--
PeteCresswell
(PeteCresswell)
>Better hub dynamos have an internal resistance of around 2 Ohms - compared
>to the 6 Ohms of the old SA Dynahub. Those hub dynamos can easily drive 4
>LEDs in series.
Care to comment on somebody else's suggestion to flip the
polarities on two LEDs - so one half of the AC sine wave drives
one and the other half of the sine wave drives the other?
Unencumbered by any knowledge of electrical stuff, it seems like
the second polarity-reversed LED is a freebie
electrical-energy-wise.
Or is there something going on where an unused half of the sine
wave doesn't add significantly to the current drawn from the
alternator?
--
PeteCresswell
SMS
> Shottky diodes like SB130 are cheap. With them 0.8 Volt is lost at the
> rectivier compared to the 3.7 Volt at each LED.
By design, a bridge rectifier is at most about 81% efficient, and with
the low voltage being rectified, the losses are worse.
With the poorer optics of LED lamps, especially where the beam needs to
be collimated from multiple LEDs, it's nearly hopeless.
What would work better if LED lamps are used is to use the dynamo to
charge one battery while another battery powers the LED. Some
rechargeable batteries are perfectly happy being charged at a wide range
of voltages. You can even buy a commercial AA charger that will charge
four AA cells from a source between 5 and 12VDC, with the higher the
voltage the faster the charging. So no fancy DC-DC converter is needed,
you can rectify the output of the dynamo and feed it directly to the
charger, with only some sort of over-voltage protection being required
(and practically speaking, no such protection is probably needed, as
with the load of the charger the dynamo is not going to get over 12 volts.
But again, it's a lot of work to solve a non-existent problem. Filament
based bulbs work just fine for dynamo lights.
SMS
> Or is there something going on where an unused half of the sine
> wave doesn't add significantly to the current drawn from the
> alternator?
The problem is that you'd be reverse biasing the LED that's off, and
you'd destroy it.
As the Luxeon datasheet states: "LEDs are not designed to be driven in
reverse bias. Please consult Lumileds' Application Brief AB11 for
further information." They don't state the maximum reverse bias current,
only to not do it!
SMS
> Tue, 18 Mar 2008 16:54:24 -0700, SMS:
>
>> Andreas Oehler wrote:
>>
>>> Shottky diodes like SB130 are cheap. With them 0.8 Volt is lost at the
>>> rectivier compared to the 3.7 Volt at each LED.
>> By design, a bridge rectifier is at most about 81% efficient, and with
>> the low voltage being rectified, the losses are worse.
>
> series after a bridge rectifier from Shottky diodes. Around 95% of the
> electrical power finds its way to the LEDs.
The maximum theoretical efficiency of a bridge rectifier is 81.2%. If
you want to see the math, go to
"http://elearning.vtu.ac.in/syllabus/PRG-III%20Notes/WEB-BASED/Basic%20Elc.Sudhendra.Compiled.doc"
In reality it will be less when the input voltage is low and the diode
voltage drop, even of Schottky diodes, is a significant percentage of
the input voltage.
> Why are LED lamp optics "poorer"? Poorer compared to what? What kind of
> LED optics are you talking about anyhow? What beam has to be collimated?
If you use a single, high power LED, then you don't run into the
collimation problem. You just can't get to the same power levels as with
a halogen lamp. But for dynamo lamps it doesn't really matter since you
can't power a higher power halogen lamp anyway.
Commercial LED dynamo lamps mostly use 1 watt LEDs. There was an attempt
to use 2W LEDs (Inolight 20+) but it is no longer available AFAIK
because it was not being driven hard enough at "normal" speeds to make
any difference in the light output versus a 10+. With all the losses in
the circuitry, 1 watt is about it. The Inolight does not have good
regulation, and is damaged at higher speeds.
So the question really comes down to whether or not a 1 watt LED
provides an advantage over a 3W halogen bulb. Look at the comparisons on
Peter White's web site of a Schmidt E6 versus and Inolight 10+. There
are also some issues with the optics, though Inolight has made the best
of it with their positioning of the emitter.
Bottom line is to carry some spare bulbs, and don't spend a lot of money
trying to make an AC dynamo designed to power halogen lamps do something
it wasn't designed for. I'm sure that eventually someone will marked DC
hub generators and/or dynamos like the Lightspin again. It's taken so
long because high efficency LEDs have only come to market in the past
year or two. Four years ago, LEDs could not match the efficiency of a
halogen bulb.
A Muzi
>>> Yes, all the effort to avoid halogen based dynamo lights in favor of
>>> LED based dynamo lights is really wasted effort. By the time you
>>> finish with the electronics you need, any theoretical efficiency gain
>>> is lost, and
> bob prohaska's usenet account wrote:
>> That's not true. No "electronics" are needed save for the LEDs
>> themselves. It's just that two or three pairs of LEDs are required.
>> Otherwise the match
>> between a bicycle dynamo and a light emitting diode is quite good.
SMS wrote:
> You can't reverse bias the LEDs, at least according to the data sheets.
> You might get away with it for a while, but you'll greatly shorten the
> service life. For example, the Cree LED specifies a maximum reverse
> voltage of 5 volts, while Luxeon just says 'don't do it.' While it's
> true that if you string three together in series you'll probably not go
> under -15V, the LEDs will only be forward biased and be on half the time
> (actually less) compared to a filament bulb. You're better off taking
> the 20% hit of the bridge rectifier than connecting them directly to the
> dynamo.
> Bicycle dynamos were specifically designed for filament bulbs, and don't
> match very well to LEDs. What's needed is a hub DC generator more suited
> to LEDs, such as the one patented by Nitto, but apparently not yet in
> production.
Regarding "Bicycle dynamos were specifically designed for filament
bulbs", weren't also common AA batteries?
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
Peter Cole
> Tue, 18 Mar 2008 16:54:58 GMT, Peter Cole:
>
>> "The ideal would be to simply have a single LED that was rated for the
>> full power output of the dynamo matched with a dynamo wound for the LED
>> characteristics. I'm not sure how close you can get to that with
>> available components."
>>
>> What was implied (though I obviously should have spelled it out) was
>> that there are two concerns for LED/dynamo lighting. First is the
>> capacity of the LED relative to the power of the generator. If you want
>> to be pedantic and insist on "current", fine. The second issue is
>> efficiency (obvious I thought in this application).
>>
>> A SA dynohub apparently has about a 6 ohm coil. At the nominal 350ma/6V,
>> you're driving a bit over 2W, with 0.7W internal losses. With a 3.5V
>> LED, you've cut the power to the light almost in half with the same
>> loss, so the relative efficiency is much less.
>
>
>> The 350ma nominal maximum output current would be too high for safe
>> operation of a 1W LED,
>
>> but well suited to a 3W one. Running this
>> unregulated off a SA would be fine, but you're only going to get ~1W to
>> it and the efficiency is bad.
>
> rear lamp.
>
>> Higher output dynohubs might be safe with unregulated 3W LEDs (barely),
>> but the efficiency would be bad.
>
> to the 6 Ohms of the old SA Dynahub. Those hub dynamos can easily drive 4
> LEDs in series.
>
>> of what the generator could deliver (3.5/6.0V). Another significant
>> factor is the rectifier losses in the (necessary) full wave bridge, that
>> alone will give a 70:30 power split (load:bridge).
>
> rectivier compared to the 3.7 Volt at each LED.
>
>> increased effect of wiring losses,
>
> losses there.
>
>> and when you add up all the effects
>> of low voltage DC lamps, the overall efficiency is bad.
>
>
>> An ideal approach (given available components) would be to wire the
>> dynohub to a rectifier/filter in the lamp and then use a switching
>> regulator to drive the LED.
>
> 80% efficiency in the most circumstances.
>
> Andreas
I think we're marching in circles.
One problem with incandescents is that they have to operate in a narrow
power range. LEDs don't have that limitation, and they're more
efficient. The problem with LEDs (relative to incandescents) is that
they're a low voltage/high current device, and so are poorly matched to
generators/alternators that are designed for incandescents. The obvious
solution is to stack LEDs (as I said in my initial post). While this is
also done with incandescents, the (again obvious) problem is the optics.
It's not a fatal problem, but it is a complication.
Getting back to the OP's original question -- how to use LEDs with a SA
Dynohub -- he could use a single 3W (with poor efficiency), he could use
2, one in front, one in back, which would give him about the same light
in front as option 1 (~1W), or he could make 2 housings and have 2 front
lights. None of these are "bad" solutions, but neither are they obvious
slam dunks over a simple incandescent.
The only reason to add a regulator to a generator/alternator LED circuit
is to either limit current or to match source to load. The first case is
frequent in battery applications to have discrete power levels, but of
no real value in generator drives, even to limit over currents since
that can be solved by over sizing the lamp.
For me, a really useful dynohub/lamp would be 3W. Given that cheap 3W
LEDs at 100+ lumen/W are almost here, a 300 lumen system would serve my
needs and only require a 3W hub -- more like a SA than SON.
I expect that in the not too distant future LEDs will entirely replace
incandescents, and as part of that transition, the permanent magnet
alternators supplied will be a better match to LEDs.
SMS
> I won't open M$-doc documents of unknown origin.
A good anti-virus program will eliminate this concern
> But those theory seems not to fit here.
Then I give up. What I want to say right now I won't say because I can't
say it nicely. But understand that the 81.2% number is not a theory,
it's the maximum possible efficiency, with an ideal diode (no voltage drop).
If you're really interested in learning about this then you can google
"81.2% bridge rectifier".
SMS
> Regarding "Bicycle dynamos were specifically designed for filament
> bulbs", weren't also common AA batteries?
No.
A Muzi
>> Regarding "Bicycle dynamos were specifically designed for filament
>> bulbs", weren't also common AA batteries?
SMS wrote:
> No.
Which sort of LEDs did they have in the 1950s? AA flashlights all used
to be filament bulb.
Frank Miles
That is a safe though simplistic answer. If you dig a bit deeper (their app-note
AB20-3), they finally reveal the reverse characteristics - which (surprise!) look
like that of an ordinary high-power LED, with a reverse breakdown voltage in the
25V area. Yes, they warn of exceeding 50uA reverse current, but this shouldn't
happen with "antiparallel" connected LEDs.
Having said all that, I haven't actually done it :)
-f
Andrew Lee
> With the poorer optics of LED lamps, especially where the beam needs to
> be collimated from multiple LEDs, it's nearly hopeless.
I don't see anything wrong with these beams:
http://ktronik.com/cncdelite/beamshots.html
These lamps can be driven by dynamo:
http://candlepowerforums.com/vb/showthread.php?p=2248317&mode=threaded#post2248317
http://candlepowerforums.com/vb/showthread.php?t=179805
> What would work better if LED lamps are used is to use the dynamo to
> charge one battery while another battery powers the LED. Some
> rechargeable batteries are perfectly happy being charged at a wide range
> of voltages. You can even buy a commercial AA charger that will charge
> four AA cells from a source between 5 and 12VDC, with the higher the
> voltage the faster the charging. So no fancy DC-DC converter is needed,
> you can rectify the output of the dynamo and feed it directly to the
> charger, with only some sort of over-voltage protection being required
> (and practically speaking, no such protection is probably needed, as
> with the load of the charger the dynamo is not going to get over 12 volts.
"Dyno-Batt"
http://www.candlepowerforums.com/vb/showthread.php?t=174596
I'm kind of out of the loop in this conversation, but at least expensive or
do-it-yourself dyno stuff looks to be very capable.
Andrew Lee
> The 350ma nominal maximum output current would be too high for safe
> operation of a 1W LED, but well suited to a 3W one. Running this
> unregulated off a SA would be fine, but you're only going to get ~1W to
> it and the efficiency is bad.
Current generation LEDs like the Seoul Semiconductor P4 (or Cree) are not
separated into 1W and 3W classes. As you can calculate from the graph
below, the Seoul P4 (max current rating 1000 mA, what you are calling 3W)
is actually more efficient at around 1W.
http://candlepowerforums.com/vb/showpost.php?p=1794431&postcount=260
SMS
> I'm kind of out of the loop in this conversation, but at least expensive or
> do-it-yourself dyno stuff looks to be very capable.
Interesting.
I noticed that Wal-Mart sells an Eveready 3 Watt rechargeable flashlight
for about $47, with the charging circuit internal. I don't know if the
circuitry allows charging during use though.
Peter Cole
Yes, I know.
Andrew Lee
> These lamps can be driven by dynamo:
> http://candlepowerforums.com/vb/showthread.php?p=2248317&mode=threaded#post2248317
meant to single out Kerry's (ktronik's) post:
http://candlepowerforums.com/vb/showpost.php?p=1794431&postcount=260
in this thread:
Andrew Lee
> Andrew Lee wrote:
>> These lamps can be driven by dynamo:
>> http://candlepowerforums.com/vb/showthread.php?p=2248317&mode=threaded#post2248317
>
> meant to single out Kerry's (ktronik's) post:
> http://candlepowerforums.com/vb/showpost.php?p=1794431&postcount=260
Oops, third try:
http://candlepowerforums.com/vb/showpost.php?p=2291971&postcount=36
frkr...@gmail.com
> 2..."
>
> I won't open M$-doc documents of unknown origin. But those theory seems
> not to fit here. The dynamo delivers 500mA and this current went through
> teh bridge rectifier and the 4 LEDs. 500mA*0.8V=0.4W is consumed by the
> bridge rectifier. 500mA*3.7V*4=7.4W powers the LEDs.
>
> Efficiency is calculated as useful power compared to total power:
In more general terms, efficiency can be broadly defined as "how much
of what you want, divided by how much you have to spend."
That broad definition is important for this situation, a generator-
powered bike light, because we really don't care much about the
efficiency of the bridge circuit. We're spending mechanical power
from our legs - or, IOW, drag. We're wanting good illumination of the
road. (We also want adequate conspicuity, but it's nearly impossible
to light the road well and not be adequately conspicuous.)
If we get better illumination with less drag, nobody cares if a
certain component in our circuit has low efficiency. Freshman physics
students might fuss about it, but practical engineers should instead
look at the overall picture.
In a bike lighting system, the efficiency of an incandescent bulb -
even a halogen one - is terrible. About 90% of the input energy goes
to heat, rather than light. If your emitter does a lot better than
that, you can afford to feed it through a 75% efficient component.
You'll still come out ahead overall.
- Frank Krygowski
SMS
> Current generation LEDs like the Seoul Semiconductor P4 (or Cree) are not
> separated into 1W and 3W classes.
This is true, but the better bins are more expensive and are used in the
higher wattage lighting products because they are able to produce more
light and less heat at a given current, and heat dissipation is the
biggest issue with LED based lamps.
> As you can calculate from the graph below, the Seoul P4 (max current
rating 1000 mA, what you are calling 3W) is actually more efficient at
around 1W.
Yes, and that's another key difference between LEDs and incandescent
lamps. The incandescents are more efficient at higher voltages, though
it shortens the bulb life.
There are some people that think LED based lamps are efficient because
of the lack of a filament, but in reality they have even more difficult
thermal issues to resolve.
(PeteCresswell)
>In a bike lighting system, the efficiency of an incandescent bulb -
>even a halogen one - is terrible.
Well, as the OP, I finally shut up and got a system.
--------------------------------------------------------
- SA (recent-model) XF-DD dynohub
- Busche & Muller HL Lumotec N2 halogen head light.
- Busche & Muller TL Seculite Plus LED tail light
--------------------------------------------------------
Coming from a hand-held Lowe's hardware "Task Master" flashlight
with 2 "C" cells and a Cree 4w emitter, I've got to say that the
halogen headlight is just plain pitiful in comparison.
On a scale of 1 to 10
Halogen headlight: .3
Lowe's handheld: 9.5
That's not to say the halogen light is not adequate for the task
- especially since many greater minds (and vastly more
experienced riders) than mine/me think they are.
But, in comparison, the lumens are simply not there.
In fact, I know a guy who injured himself fairly grievously
riding a bike path at night (with a headlight): rode right into
some sort of construction debris and/or hole. Now, having ridden
briefly with the halogen light, I understand how he managed to
do that.
OTOH, it might be an undercover safety feature at my sub-10 mph
night time riding speed: drivers see this wobbly, flickering
yellow light and it gets their attention more just because it
looks so out of place. -)
OTOOH, the tail light seems tb pretty decent. Gives out what I'd
call sufficient light, and has a stand light feature that shines
just as brightly when the bike is stopped.
My original intent was to hang several of those things on the
back, leaving only a token LED front light - all lights always
on.... but my limited knowledge of electricity led me to the
conventional path.
All-in-all, the system does what I set out to do: give my back
some visibility and keep me out of jail of some cop wants to be a
dick about having to have a "real" bicycle headlight.
But in the end, although I'll turn on the dynohub system and feel
better about my visibility from behind, I'll keep using the
Lowe's 4w Cree-based flashlight. That is one *brave* little
flashlight.
--
PeteCresswell
frkr...@gmail.com
> Per frkry...@gmail.com:
How's the battery life? (And with what kind of battery?)
- Frank Krygowski
(PeteCresswell)
>bins
?
--
PeteCresswell
SMS
> Per frkr...@gmail.com:
>> In a bike lighting system, the efficiency of an incandescent bulb -
>> even a halogen one - is terrible.
>
> Well, as the OP, I finally shut up and got a system.
>
> --------------------------------------------------------
> - SA (recent-model) XF-DD dynohub
>
> - Busche & Muller HL Lumotec N2 halogen head light.
>
> - Busche & Muller TL Seculite Plus LED tail light
> --------------------------------------------------------
>
> Coming from a hand-held Lowe's hardware "Task Master" flashlight
> with 2 "C" cells and a Cree 4w emitter, I've got to say that the
> halogen headlight is just plain pitiful in comparison.
Task Force, not Task Master. Yes, this is true. But you're running the
Cree LED at a much higher current. You couldn't drive the Lowe's Cree
LED flashlight from a dynamo.
Look at Peter White's comparison between the Inolight 10+ and the
Schmidt E6 at "http://www.peterwhitecycles.com/inoled.asp"
"You can see that in the E6 beam on the left, the very top of the beam
is quite a bit brighter than the rest, and brighter than any part of the
Inolight 10+ beam. So the E6 can light up the road further away from you
than the Inolight 10+ can. In other words, you can aim the very top of
the E6 beam further down the road and still have a brightly lit road
surface. That will help if you're riding fast. So for fast cyclists, the
E6 will still be preferred. However, for the slower cyclist, the
Inolight projects a much wider beam, enabling you to see a much wider
section of the road ahead of you. Some of our customers complain that
the E6 isn't as wide as they would like. The bright part of the Inolight
beam is almost 50% wider than the E6, and the total width of the beam is
almost twice that of the E6.
This makes the Inolight an ideal headlight for commuting. Notice that
except for the very top of the E6 beam, the rest of the E6 beam is not
as bright as the Inolight 10+ beam. Overall, when riding, the effect of
the Inolight 10+ is similar to the E6, except for you being able to see
further with the E6. And with the wider beam, you have a better sense of
seeing the entire road ahead, rather than a narrow path through the
road. This is true on roads that are otherwise unlit. In urban areas
with street lights, it's of course very different."
Peter has pointed out the biggest problem with the E6, which is the
narrow path, but that's an intentional design of the E6.
The issue is really that the efficiency of an LED in a dynamo system is
far less than it is in a battery powered system, while an incandescent
bulb is of equal efficiency whether it's powered by a dynamo or a
battery (well not exactly equal, but close).
Actually the most efficient lamp for bicycle lighting at this juncture
is an HID incandescent or an over-voltaged non-HID incandescent, but I
just don't think HID will make it to the mainstream of bicycle lighting
due to cost, and over-voltaging non-HID bulbs results in too-short lamp
life for some (though the lamps are very cheap, so it's really all about
just carrying a spare). There was one company at Taipei Cycle
wholesaling good HID systems for $108. Still, by the time it's shipped
over and sold at retail, it'll be around $200. Within a few years the
LED manufacturers will improve their processes to the point where
they'll get more light and less heat from their designs.
> But in the end, although I'll turn on the dynohub system and feel
> better about my visibility from behind, I'll keep using the
> Lowe's 4w Cree-based flashlight. That is one *brave* little
> flashlight.
Alas, not sure it's still available.
BTW, how did you fasten it to the handlebars? I build a pretty good
handlebar holder from a Driftmaster rail clamp, a piece of aluminum flat
bar, and a pair of Nite Ize Delrin clamps. Took only about ten minutes.
I also built one for an AA flashlight but with a different type of bar
clamp. See: "http://nordicgroup.us/s78/flashlights.html" for details and
photos.
There was a really cool bar mount flashlight holder at Taipei Cycle, and
I may import them soon, but it was only a prototype. I brought along one
of the Lowe's Task Force headlights to the show so I could try various
flashlight holders, but there was only one at the entire show!
SMS
> Per SMS:
>> bins
>
> ?
When semiconductors come off the line, the parts are tested for various
characteristics and divided into bins. I.e. for microprocessors they
test for maximum clock rate and thermals. For LEDs they test for light
output and thermals at different currents. The best quality ones fetch
higher prices.
The no-name notebook computers typically buy the CPUs that no one else
wants because they are higher power with poorer battery life and more
heat to dissipate.
bob prohaska's usenet account
>
> You can't reverse bias the LEDs, at least according to the data sheets.
> You might get away with it for a while, but you'll greatly shorten the
> service life. For example, the Cree LED specifies a maximum reverse
> voltage of 5 volts, while Luxeon just says 'don't do it.' While it's
> true that if you string three together in series you'll probably not go
> under -15V, the LEDs will only be forward biased and be on half the time
> (actually less) compared to a filament bulb. You're better off taking
> the 20% hit of the bridge rectifier than connecting them directly to the
> dynamo.
parallel, and drive the common point with AC. The reverse bias is never
more than the forward drop, which presents no problems. Peak current can
be increased so long as average current is not exceeded. Series pairs
allow increased voltage with no per-diode increase in reverse voltage.
> Bicycle dynamos were specifically designed for filament bulbs, and don't
> match very well to LEDs.
Bicycle dynamos were designed to deliver about half an amp, roughly independent
of speed. That's a near-perfect match to an appropriately-sized set of LEDs
chosen to to match the voltage presented at normal riding speeds.
> What's needed is a hub DC generator more suited
> to LEDs, such as the one patented by Nitto, but apparently not yet in
> production.
All generators produce AC and require some sort of commutation, with its
attendant losses, to make DC. It could be mechanical, it could be electronic,
but why not use the LED as a self rectifier? Simple, cheap and effective:
http://www.zefox.net/~bob/bicycle/
bob prohaska
Peter Cole
What you are talking about is "rectification efficiency". A rectified
sine wave will have a DC component and an AC component ("ripple").
Rectification efficiency is related to ripple factor, it has nothing to
do with power efficiency.
Peter Cole
> There are some people that think LED based lamps are efficient because
> of the lack of a filament, but in reality they have even more difficult
> thermal issues to resolve.
The thermal design issues of incandescent and solid state lamps are
opposite. A filament works by heating to incandescence, so in effect,
"heat is good", you want to insulate the filament. For solid state
devices, heat is bad, for a variety of reasons. From an efficiency POV,
heat is just radiation in the non-visible spectrum, efficiency just
being the ratio of visible to non-visible radiation.
Peter Cole
> In a bike lighting system, the efficiency of an incandescent bulb -
> even a halogen one - is terrible. About 90% of the input energy goes
> to heat, rather than light. If your emitter does a lot better than
> that, you can afford to feed it through a 75% efficient component.
> You'll still come out ahead overall.
All this is true, but the typical bike generators today are designed for
incandescents. With a few design changes they would be much better
(smaller, lighter, cheaper) for driving LEDs.
My ideal bike light would be a sidewall bottle with an
integrated/matched 3W LED. Something like that ought to cost $50 and put
out 300 lumens.
Another interesting option with LEDs is to use a color other than white.
Theory says that our vision sensitivity peaks at around 550nm, dim light
monochromatic vision at around 500nm. That means that a monochromatic
source at that wavelength might be around 2.5x more efficient.
Currently, green power LEDs are available that produce 70 lumens/watt.
This would give an effective (relative to white) almost 200 lumens/watt.
I don't know how well practice would match theory, it would be an
interesting experiment.
(PeteCresswell)
>How's the battery life? (And with what kind of battery?)
Two C cells.
Dunno yet - except that I accidentally left it on for one or two
days once and it was still putting out light. Only about as
much as a normal flashlight, and I replaced the batteries right
away... but it was still tickin' and it definitely doesn't chew
up batteries right and left.
--
PeteCresswell
SMS
>> You can't reverse bias the LEDs, at least according to the data sheets.
>> You might get away with it for a while, but you'll greatly shorten the
>> service life. For example, the Cree LED specifies a maximum reverse
>> voltage of 5 volts, while Luxeon just says 'don't do it.' While it's
>> true that if you string three together in series you'll probably not go
>> under -15V, the LEDs will only be forward biased and be on half the time
>> (actually less) compared to a filament bulb. You're better off taking
>> the 20% hit of the bridge rectifier than connecting them directly to the
>> dynamo.
> Ahh, but you're missing the whole point: Use a pair of LEDs wired inverse
> parallel, and drive the common point with AC.
Argh, please don't do this. It's extremely annoying.
(PeteCresswell)
>Alas, not sure it's still available.
I bought a half-dozen for gifts last week at a Lowe's in the
Philadelphia area. Hopefully it wasn't the last of them.
>BTW, how did you fasten it to the handlebars?
I went low tech: http://tinyurl.com/26ng7t
For my kind of night riding, it's actually quite useful.
With a bracket, the light's direction is fixed. OTOH, I want to
flip it from side to side sometimes to make sure there aren't any
eye-level tree branches.
--
PeteCresswell
SMS
> frkr...@gmail.com wrote:
>
>> In a bike lighting system, the efficiency of an incandescent bulb -
>> even a halogen one - is terrible. About 90% of the input energy goes
>> to heat, rather than light. If your emitter does a lot better than
>> that, you can afford to feed it through a 75% efficient component.
>> You'll still come out ahead overall.
>
> All this is true, but the typical bike generators today are designed for
> incandescents. With a few design changes they would be much better
> (smaller, lighter, cheaper) for driving LEDs.
It's not just "a few design changes," either. It's a significant change.
It's been done (or at least designed). See
"http://www.wipo.int/pctdb/en/wo.jsp?wo=2006016397". Actual production,
is far in the future, if ever. It's almost chicken and egg though.
Self-powered lighting continues to decrease in popularity around the
world because newer battery powered lighting is so much more efficient,
yet if there were good (and cheap) DC generators available that could
power LEDs properly then self-powered lighting would become more viable.
> My ideal bike light would be a sidewall bottle with an
> integrated/matched 3W LED. Something like that ought to cost $50 and put
> out 300 lumens.
You won't see a single 3W LED on a dynamo for now for reasons that have
already been explained.
But see "http://www.kmc-drrider.com/product_info.php?id=70"
There's another option as well. If you could design a dynamo with a
higher frequency output you could design a custom switching regulator
that didn't first have to convert the AC to DC. At the current time
you're stuck with the losses of rectifying the AC to DC, and the
additional losses of a switching regulator (as used in the high end LED
lights which is converting the DC to AC internally then back to DC), and
as was used in the LightSpin (I believe). Eliminate one conversion and
you could boost the efficiency from what's currently around 50%, up to
70-80%.
SMS
> For my kind of night riding, it's actually quite useful.
> With a bracket, the light's direction is fixed. OTOH, I want to
> flip it from side to side sometimes to make sure there aren't any
> eye-level tree branches.
Actually, with this bracket I made
("http://nordicgroup.us/s78/images/barbracketcree.jpg") the light
direction is adjustable both up and down, and side to side). Using the
rail clamp in the later design, it's adjustable side to side, and if you
don't tighten it too much, up and down as well.
I should have used an acorn lock nut and a shorter bolt to make it look
better, but the acorn lock nuts have to be special ordered from McMaster.
frkr...@gmail.com
wrote:
>
>
> Ahh, but you're missing the whole point: Use a pair of LEDs wired inverse
> parallel, and drive the common point with AC. The reverse bias is never
> more than the forward drop, which presents no problems. Peak current can
> be increased so long as average current is not exceeded. Series pairs
> allow increased voltage with no per-diode increase in reverse voltage.
About the "peak current:" When LED data sheets show a maximum
current, they're referring to DC current. If (as I believe) they're
really trying to limit thermal problems at the junction, then RMS
current would be the appropriate measurement for an AC source like a
bike generator.
But since your (i.e. Bob's) wiring scheme puts only half the AC wave
through a given LED, your RMS current is only half of what's normal
for AC. IOW, you should have even fewer problems with heat sinking,
etc. I like it.
Not sure why Scharf says your design is "very annoying."
- Frank Krygowski
Peter Cole
>> My ideal bike light would be a sidewall bottle with an
>> integrated/matched 3W LED. Something like that ought to cost $50 and
>> put out 300 lumens.
>
> You won't see a single 3W LED on a dynamo for now for reasons that have
> already been explained.
The only thing that has been explained is the inefficiency of the
current generators with a single LED.
> But see "http://www.kmc-drrider.com/product_info.php?id=70"
>
> There's another option as well. If you could design a dynamo with a
> higher frequency output you could design a custom switching regulator
> that didn't first have to convert the AC to DC. At the current time
> you're stuck with the losses of rectifying the AC to DC, and the
> additional losses of a switching regulator (as used in the high end LED
> lights which is converting the DC to AC internally then back to DC), and
> as was used in the LightSpin (I believe). Eliminate one conversion and
> you could boost the efficiency from what's currently around 50%, up to
> 70-80%.
I agree with Andreas in that I don't see the need for a regulator if the
generator is matched to the load. I don't even see the problem with a
multiple emitter stack if the optics are integrated into a single
housing (as the example you show). 3 of the available high efficiency
LEDs would provide 300 lumens with 1 amp from the generator. If the
generators simply reduced the winding turns, they would raise the short
circuit current and lower the resistance enough to make it work much
better with a single LED.
Frank Miles
On Thu, 20 Mar 2008, frkr...@gmail.com wrote:
[snip]
> About the "peak current:" When LED data sheets show a maximum
> current, they're referring to DC current.
No, this refers to an "instantaneous" current level - which is independent
of waveform. Of course, operating near an absolute maximum typically
reduces the lifetime/reliability of a given device.
> If (as I believe) they're
> really trying to limit thermal problems at the junction, then RMS
> current would be the appropriate measurement for an AC source like a
> bike generator.
[snip]
Absolutely! In fact, many high quality RMS voltmeters used the heating
effect of the voltage to make that measurement.
-f (E.E.)
SMS
> SMS wrote:
>
>>> My ideal bike light would be a sidewall bottle with an
>>> integrated/matched 3W LED. Something like that ought to cost $50 and
>>> put out 300 lumens.
>>
>> You won't see a single 3W LED on a dynamo for now for reasons that
>> have already been explained.
>
> The only thing that has been explained is the inefficiency of the
> current generators with a single LED.
>
>> But see "http://www.kmc-drrider.com/product_info.php?id=70"
>>
>> There's another option as well. If you could design a dynamo with a
>> higher frequency output you could design a custom switching regulator
>> that didn't first have to convert the AC to DC. At the current time
>> you're stuck with the losses of rectifying the AC to DC, and the
>> additional losses of a switching regulator (as used in the high end
>> LED lights which is converting the DC to AC internally then back to
>> DC), and as was used in the LightSpin (I believe). Eliminate one
>> conversion and you could boost the efficiency from what's currently
>> around 50%, up to 70-80%.
>
> I agree with Andreas in that I don't see the need for a regulator if the
> generator is matched to the load.
Very difficult to do this with no regulation.
I don't even see the problem with a
> multiple emitter stack if the optics are integrated into a single
> housing (as the example you show). 3 of the available high efficiency
> LEDs would provide 300 lumens with 1 amp from the generator.
Yes it might be sufficient. However it is less efficient than a single
LED in terms of lumens/watt.
> If the
> generators simply reduced the winding turns, they would raise the short
> circuit current and lower the resistance enough to make it work much
> better with a single LED.
Yes, but then you've doubled the number of different dynamos needed,
unless the new design could be made to work equally well with
incandescent lamps.
Andre Jute
Eh? Why no? What Bob has done is clever. I did it too, without ever
having heard of Bob. Now that I've read it, I like his simple
explanation and his simple diagram: makes everything brilliantly
clear. I didn't continue the experiment because I'm not having
anything that ugly on my bike, but that's an aesthetic judgement,
nothing to do with electronics that work. (It's a different matter
that my next experiment, an overvolted 20W MR16 operated on batteries,
provided *vastly more* light.)
Andre Jute
http://members.lycos.co.uk/fiultra/BICYCLE%20%26%20CYCLING.html
Andre Jute
Yeah. This is where we came in: A battery system by itself cannot
provide 100% security, because the battery can run out. A dynohub
system by itself does not deliver enough light for all purposes.
Therefore the thoughful cyclist fits both a dynohub and a battery
light set, and uses them as appropriate. And ignores the outrages
screeching of the to-the-death partisans of either.
Congratulations on achieving a working system that suits you, Pete.
I'm still looking for that flashing front light, and my rear lights
are currently all battery, which isn't quite good enough.
Thanks for a most worthwhile thread, Pete. Even if I had little to
say, I read all the posts carefully, so thanks to all the contributors
to Pete's thread from me too.
Andre Jute
http://members.lycos.co.uk/fiultra/BICYCLE%20%26%20CYCLING.html
Andre Jute
> Per SMS:
>
> >Alas, not sure it's still available.
>
> I bought a half-dozen for gifts last week at a Lowe's in the
> Philadelphia area. Hopefully it wasn't the last of them.
>
> >BTW, how did you fasten it to the handlebars?
>
> I went low tech:http://tinyurl.com/26ng7t
Never mind low tech. I love the pics that illustrate why cyclists wear
black shorts!
http://www.flickr.com/photos/48262653@N00/339745153/in/set-72157594449980969/
And I thought it was because SUV drivers frightened them. -- AJ
SMS
> Eh? Why no? What Bob has done is clever. I did it too, without ever
> having heard of Bob. Now that I've read it, I like his simple
> explanation and his simple diagram: makes everything brilliantly
> clear.
I've seen these set ups and they flicker as the LEDs alternate being
illuminated. If he's eliminated the flickering, and isn't reverse
biasing the LEDs, then I stand corrected.
I didn't continue the experiment because I'm not having
> anything that ugly on my bike, but that's an aesthetic judgement,
> nothing to do with electronics that work. (It's a different matter
> that my next experiment, an overvolted 20W MR16 operated on batteries,
> provided *vastly more* light.)
It would be nice to have a hybrid system without having two separate
fixtures. A battery powered MR16 lamp for a "seeing" lamp, and a dynamo
powered lamp for a "being seen" light or simply as a back-up in case
your batteries go dead. You could also choose to charge the battery of
the MR16, at least partially, from the generator. A "plug-in" hybrid
type solution.
SMS
> Yeah. This is where we came in: A battery system by itself cannot
> provide 100% security, because the battery can run out. A dynohub
> system by itself does not deliver enough light for all purposes.
> Therefore the thoughful cyclist fits both a dynohub and a battery
> light set, and uses them as appropriate. And ignores the outrages
> screeching of the to-the-death partisans of either.
It would be possible to have a dynohub that is sufficient, but it seems
there is no interest in a dynohub with any more drag or any more cost.
Even just a 12W dynohub would be able to power sufficient lights for
most purposes.
SMS
> Just to be clear about these terms...
>
> On Thu, 20 Mar 2008, frkr...@gmail.com wrote:
>
> [snip]
>
>> About the "peak current:" When LED data sheets show a maximum
>> current, they're referring to DC current.
>
> No, this refers to an "instantaneous" current level - which is independent
> of waveform. Of course, operating near an absolute maximum typically
> reduces the lifetime/reliability of a given device.
Yes, you have to be careful about continuous operation at "absolute
maximum" ratings.
> Absolutely! In fact, many high quality RMS voltmeters used the heating
> effect of the voltage to make that measurement.
Actually, one cheap solution, once you have implemented a
micro-controller based system anyway, is to have a temperature sensor
that reduces the current when the temperature gets too high. This is an
especially good solution for bicycle lighting because the light gets
forced air cooling over the heat sink when in motion, but no forced air
when stopped. The faster you ride, the more light is needed and the more
cooling effect you get. Some sockets for high power LEDs have integrated
fans, but this is getting a bit ridiculous for bicycle lights.
frkr...@gmail.com
> Just to be clear about these terms...
>
>
> [snip]
>
> > About the "peak current:" When LED data sheets show a maximum
> > current, they're referring to DC current.
>
> No, this refers to an "instantaneous" current level - which is independent
> of waveform.
I don't think so. At least, not for this emitter:
http://www.cree.com/products/pdf/XLamp7090XR-E.pdf
Take a look at page 4. They list the "maximum DC forward current" as
either 1000mA or 700mA, depending on model; but for both models, they
list the "Maximum DC Pulse Current (@ 1 kHz, 10% duty cycle)" as 1.8
A. Obviously, they're pointing out that the instantaneous current can
be higher than the normal "maximum" current.
Yes, their phrasing is a bit misleading (allowing a "peak" higher than
a "maximum") but the numbers make the situation clear.
> > If (as I believe) they're
> > really trying to limit thermal problems at the junction, then RMS
> > current would be the appropriate measurement for an AC source like a
> > bike generator.
>
> [snip]
>
> Absolutely!
Which means Bob's LEDs should last a long, long time.
- Frank Krygowski
SMS
> Misunderstanding. I use a flashing Cateye 1100 at the rear for a
> daylight running lamp. I want a flashing light at the front for a
> daylight running lamp. It would be great to be able to run it off the
> dynohub but no such lamp is available at a reasonable price. (The
> SolidLights 1203D is a dynohub LED light with a flashing mode but it
> is very expensive.) So I thought I might add a little DIY electronics
> and make my Fly IQ flash...
I can't remember which was the thread discussing tail lights, but I did
see two good tail lights from Trek recently. The Flare 7 ($25) uses
seven very bright LEDs and provides 270 degree coverage. The Flare 10
($30) uses ten LEDs and provides 360 degrees coverage (which I find hard
to believe!). I guess I'd still opt for the TL-DL1100, but at least
there are a couple of more choices now.
Andre Jute
Because of my other hobby, tube audio amplifiers (see Jute on Amps at
http://members.lycos.co.uk/fiultra/ ), I know just about every high-
class wound magnetics custom specialist in the world. I could probably
get an existing hub rewound to 12V. But the problem is that I already
committed myself to the Cyber Nexus Groupset; the automatic gearbox
(which works well with my heart rate monitor to set my exercise rate
much more precisely than cadence can) is far more important to me than
lights can ever be (I work at home; I don't commute). So I'm tied in
to 6V electronics for the foreseeable future -- and I hope my Cyber
Nexus groupset will remain serviceable for the rest of my life. It
would be a waste for which my engineering chums will tar and feather
me to lash out on a custom 12V hub and then waste half of it in heat
to provide 6V for the Cyber Nexus electronics.
I looked at the BUMM 12V dynamo and thought it goddamn pricey for a
sidewall generator and, anyway, one of the main reasons I went to a
hub dynamo was because I find the stuck-on aesthetics of sidewall
dynamos most unappealing. Wasn't the SON chappie talking about a 12V
hub dynamo at one point? That might be worth lashing out for even at
his prices and even with my reluctance to depart from the cheap and
exceedingly fine standard Shimano sets in whichever component field
they enter.
Andre "You get more from Shimano" Jute
http://members.lycos.co.uk/fiultra/BICYCLE%20%26%20CYCLING.html
frkr...@gmail.com
>
>
> Wasn't your topic efficiency? A Cree XRE 7090 Q5 (and the best Luxeon
> Rebel too) reach 100 lm/W at medium power levels - if properly cooled.
> Small halogen bulbs of high quality don't deliver more than 20-25 lm/W.
> You loose some of the efficiency adavantage by the need of a rectifier and
> maybe other electronics and maybe not so refined optics - but the
> efficiency adavantage of high power LEDs is so big...
>
> But you are right in one aspect: There are a lot of LED lamps out there
> with so terrible electronics and optics that even cheap dynamo lamps with
> halogen bulbs give a more useful light, especially in the regard of
> vertical light distribution.
Andreas (and others) - any general tips on optics for LED homebrews?
I've briefly bench-tested two Crees powered by an antique Sturmey-
Archer Dynohub. The number of lumens seems satisfying (at least in my
dark workshop), but the beam seems very diffuse and undefined.
Especially, as you say, in regard to vertical light distribution.
What I'd like is a pattern tailored for road use, as I've described
elsewhere - not a lot wasted upwards, and ideally, brighter toward the
horizon.
I'd given some thought to hack-sawing into some of my old light
shells, but I'd prefer a bit of guidance over raw trial and error.
Anything to recommend?
- Frank Krygowski