More About Lights

[cycl...@gmail.com]

Since you people have been talking about lights I've been looking. Like sms I really don't like the idea of having normal batteries that wear out quickly or the idea of always keeping your battery on charge.

This means you need a bulb generator or a hub generator. The hub generator seems a good answer but they don't appear to make half of the power of a bulb generator.

But that's a little hard to tell since they seem to have a great deal of trouble listing the output of the various dynamos.

You can get a 6 watt bulb generator but the hubs appear to all deliver 3 watts.

Now there are extremely efficient hubs that even Frank wouldn't have any trouble peddling in his old broken down and crippled state.

But when you look up the lights you find the same problem - you have a very difficult time finding power in and lumens out.

There are a few things that I really like the idea of in a commuter bike:

A front wheel hub generator - the German Schmidt which is extremely reliable and apparently is 78% efficient so Jorge could not complain that he is having trouble pedalling against the tide.

The Shimano Alfine is an 11-speed rear hub which has the decided advantage of being able to put a total cover chain guard around the entire chain and SINGLE SPEED front ring and still be able to leap tall buildings in a single bound.

Now building this set of wheel would cost the better part of a thousand dollars and we're all a bunch of cheapskates.

But with bikes costing $5K+ I'm sure you could build the perfect commuter for half that amount.

[Sir Ridesalot]

Once again; *SOME PEOPLE PREFER THE CONVENIENCE OF BATTERY LIGHTS FOR THEIR OWN USES!*

If I had to spend $2,500.00 for a commuter bicycle I'd seriously look at a used car just for commuting.

Cheers

[cycl...@gmail.com]

I don't recall forcing anything on you. Or do you simply object to opinions?

[Jeff Liebermann]

On Sun, 5 Mar 2017 10:56:09 -0800 (PST), cycl...@gmail.com wrote:

>But when you look up the lights you find the same problem - you
>have a very difficult time finding power in and lumens out.

Hint: Measuring lumens is messy and expensive. Here's what it took
to verify lumens in 2014:
<http://www.roadbikereview.com/reviews/2014-bike-lights-shootout-lumen-measurements>
(I like the lumens/dollar bar graph).

For numbers and beam pattern photos, try:
<https://www.bikelightdatabase.com>
<http://reviews.mtbr.com/2016-bike-lights-shootout-lumen-measurements>
<http://reviews.mtbr.com/2016-bike-lights-shootout-beam-patterns>
<http://road.cc/content/buyers-guide/212914-updated-your-guide-best-front-lights-cycling-beam-comparison-engine>
<http://www.roadbikereview.com/reviews/2014-bike-lights-shootout-tunnel-beam-patterns>
There are others, but that's what I found in my bookmark collection.
There are also comparisons and tests on YouTube.

--
Jeff Liebermann je...@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

[Sir Ridesalot]

BUT you did NOT express an opinion. You said: > > On Sunday, March 5, 2017 at 1:56:13 PM UTC-5, cycl...@gmail.com wrote:
> > > Since you people have been talking about lights I've been looking. Like sms I really don't like the idea of having normal batteries that wear out quickly or the idea of always keeping your battery on charge.
> > >
> > > This means you need a bulb generator or a hub generator. The hub generator seems a good answer but they don't appear to make half of the power of a bulb generator."

You intaht case is not myself nor is it a lot of other people who prefer battery powered lights for whatever reasons thosepeople have.

Cheers

[Barry Beams]

Several items:
Scale heat by 1:1, because a light along with the driver circuit is not a theoretically perfect system. My package's heatsink can cool 20 watts of heat to stay under 65C on the hottest outside point for seven minutes, at 72F/ 21C. It stays under ~50C with only a 6mph/10kph airflow.
Patent number:8662697.

Burn time:
What if you had five or ten hours battery time at your generator's brightness? My Oculus gives at least that much brightness, and a quickly field replaceable battery so you can put in a fresh battery. Other rechargeables leave you out of light and out of luck when the battery drains.
Oculus also comes with a spare battery included.

Lumens per dollar: 1800/150 = 12.
Lumens per gram: 1800/205 (with 18650, bracket and strap included) = 8.8

Diffusers and arrays generate huge amounts of glare vs the usable visibility that they create in the primary field of view that the eyes pay attention to.

Btw MTBR is pay for play. Discreetly, obscurely, but pay for play for sure. They also take deliberately altered pictures.
See:
https://drive.google.com/drive/folders/0B2LXQcJ2c2wWMzVuNFdid1Z5a2c?usp=sharing
These are pics that Francis posted on his personal Facebook with a defaming title and captions. Note the overexposure/underexposure of the far horizon blue tine, and white light dots in the distance. Also the biased center weighted versus full field light metering.
He pulled the pics and posting, but refuses to test my lights or make any mention of them on his websites. I'll put my Oculus 1800 against ANYTHING he thinks is the best of anything.
Side by side with the L&M Taz, along with the head of L&M, we see my light and the his light as neither absolute superiority in terms of the raw beam the lights put out. Roadies mostly prefer my beam over the Taz right away, some MTB riders like the Taz' beam.
Honest side by side beam pictures on trails and roads will show that, not the skewed crap in favor of a big MTBR support that Francis posted.

[cycl...@gmail.com]

Thanks Jeff. These however all appear to be battery powered lights. We were sort of looking for lights that operated on the hub dynamo of 6V 3W or the Globe dynamo of 12V 6W or four times the power.

This is why the hub generator has so little drag.

[cycl...@gmail.com]

Well, I didn't realize that English isn't your first language. So rather than me changing my comments I suggest that you learn English.

[Jeff Liebermann]

On Sun, 5 Mar 2017 16:03:30 -0800 (PST), cycl...@gmail.com wrote:

>Thanks Jeff. These however all appear to be battery powered
>lights. We were sort of looking for lights that operated on
>the hub dynamo of 6V 3W or the Globe dynamo of 12V 6W or
>four times the power.

Sorry, I thought you were still open to looking at battery powered
lights. Here's what I fished out of my bookmark dumpster. No reviews
and few tests, but some interesting dynamo graphs and numbers:
<http://www.myra-simon.com/bike/dynotest.html>
<http://pilom.com/BicycleElectronics/DynamoCircuits.htm>
<http://www.eeweb.com/blog/extreme_circuits/power-mosfet-bridge-rectifier>

This one is well worth reading (or skimming) and has quite a few test
results:
<http://swhs.home.xs4all.nl/fiets/tests/verlichting/index_en.html>

>This is why the hub generator has so little drag.

Well, let's do some arithmetic. If your dynamo is rated at 3 watts,
and your lighting is rated at 70 lumens/watt, then the most you can
perhaps deliver is 210 lumens. 6 watts will get perhaps 420 lumens.
Usually, it's less as the losses accumulate. Rectification losses,
optical losses, heat degradation, and connector losses all conspire to
produce lower output.

You might find it useful to know how bright you want your light. For
that, you'll need a Lux meter. I have a Lutron LX-102 which works
nicely, and two junk meters I bought on eBay for sanity checks:
<http://www.ebay.com/sch/i.html?_nkw=lux+meter>
Get one that has a wide range. Lowest on mine is 1000 lux, and
highest range is 50,000 lux.

Find a dark night and an accomplice to operate the meter and send them
down the road to the farthest distance that you might want to
illuminate with your headlight. Use a headlight or flashlight to
light up that area. Have your accompli's take a reading. It will
probably be zero. Now, cut the distance in half and take a
measurement. It will be 2x as bright (lux) at half the distance or 4x
as bright at 1/4th the distance. Adjust the brightness for what it
would have been if the light meter was sufficiently sensitive.

Converting the brightness (lux) to luminous flux (lumens) requires
that you know the distance to the accomplice, and the illumination
angle. (1 lux = 1 lumen/square-meter)

The form below makes a mess of bad assumptions but is good enough for
a rough approximation:
<https://www.ledrise.com/shop_content.php?coID=19>
Once you know how many lumens you think you need, and have adjusted
for overly ambitious expectations, you can determine which lighting
technology is suitable.

Lets say you want to see 8 meters ahead and 20 degrees to each side
(or 40 degree conical beamwidth) at 20 lux, which is rather dim.
Plugging into the web page above, I get 485 lumens needed. You won't
be able to do that with a 3w dynamo, but might squeeze by with a 6w
and an oval shaped beam.

[Jeff Liebermann]

On Sun, 05 Mar 2017 17:26:21 -0800, Jeff Liebermann <je...@cruzio.com>
wrote:

>Find a dark night and an accomplice to operate the meter and send them
>down the road to the farthest distance that you might want to
>illuminate with your headlight. Use a headlight or flashlight to
>light up that area. Have your accompli's take a reading. It will
>probably be zero. Now, cut the distance in half and take a
>measurement. It will be 2x as bright (lux) at half the distance or 4x
>as bright at 1/4th the distance. Adjust the brightness for what it
>would have been if the light meter was sufficiently sensitive.

No brain today. That should be half the distance equals 4 times as
bright and 1/4th the distance equals 16 times as bright.

[James]

On 06/03/17 10:22, Barry Beams wrote:

>
> Burn time: What if you had five or ten hours battery time at your
> generator's brightness? My Oculus gives at least that much
> brightness, and a quickly field replaceable battery so you can put in
> a fresh battery. Other rechargeables leave you out of light and out
> of luck when the battery drains. Oculus also comes with a spare
> battery included.
>

What if I don't want to play with batteries?


--
JS

[James]

On 06/03/17 12:26, Jeff Liebermann wrote:
>
> Well, let's do some arithmetic. If your dynamo is rated at 3 watts,
> and your lighting is rated at 70 lumens/watt, then the most you can
> perhaps deliver is 210 lumens. 6 watts will get perhaps 420 lumens.
> Usually, it's less as the losses accumulate. Rectification losses,
> optical losses, heat degradation, and connector losses all conspire to
> produce lower output.

We know that a 3W dynamo is quite capable of delivering more power than
3W, once the bicycle speed increases. 6W from a 3W dynamo is quite
achievable, and the retardation torque drops off as speed increases too.

--
JS

[DATAKOLL MARINE RESEARCH]

Assumptions or measured ?

[Jeff Liebermann]

On Mon, 6 Mar 2017 17:04:13 +1100, James <james.e...@gmail.com>
wrote:

Maybe:
<http://www.myra-simon.com/bike/dynotest.html>
See "Electrical Output" graph.

Kinda looks like all of them will sorta deliver 2.5 watts before the
core saturates (to provide some level of voltage regulation). Further
down the page is a "Low Speed Power" graph, which shows that most can
produce 2.0-2.5 watts at 10km/hr. One could assume that the dynamo
will deliver 4.0 watts, but that would require buying one of the few
better (hub) dynamos listed, and riding at 25-30km/hr (15-19mph).

If I were designing or sizing a lighting system suitable for my slow
style of "cruising", I would use the worst case 10km/hr (6mph) and 2.0
watt figures.

[AMuzi]

I don't know about currents but 6V 4W bulbs for standard
dynamo systems have been around for twenty years and some
customers like them. I don't know if the dynamo drag is
noticeably greater.

--
Andrew Muzi
<www.yellowjersey.org/>
Open every day since 1 April, 1971

[cycl...@gmail.com]

As a very occasional night rider I am interested in battery powered lights but I think that I was attempting to give a thought to a commuter that would use his light a great deal.

I notice that a large number of the people in our group have flashing red rear lights and it isn't long before these batteries run down enough that the taillight even blinking is almost entirely unnoticeable. So I don't have much respect for battery power for a great deal of use.

[Sir Ridesalot]

On Monday, March 6, 2017 at 1:47:41 PM UTC-5, cycl...@gmail.com wrote:
> On Sunday, March 5, 2017 at 5:26:18 PM UTC-8, Jeff Liebermann wrote:

Snipped

> I notice that a large number of the people in our group have flashing red rear lights and it isn't long before these batteries run down enough that the taillight even blinking is almost entirely unnoticeable. So I don't have much respect for battery power for a great deal of use.

I have a rear red light I bought from MEC (Mountain Equipment Co-op)along with a front light that came with the five AAA batteries (2= rear, 3 = front)that were less than $15.00 for the pair and that rear light on flashing mode lasts for months and I do a LOT of night time riding.

Cheers

[jbeattie]

Then you're done with the battery light discussion and may move on to helmets.

-- Jay Beattie.

[Sir Ridesalot]

or carbon frames versus steel frames.

Cheers

[Frank Krygowski]

6V 4W? I'm aware of 6V 3W bulbs, which are (or were) used mostly with bottle
dyno systems when driving a headlamp but no taillamp. They were an alternative
to 2.4 W in front and 0.6W in back.

I'm not aware of any common use of 6V 4W bulbs.

- Frank Krygowski

[David Scheidt]

Frank Krygowski <frkr...@gmail.com> wrote:

It's a standard lantern size.

--
But all of a sudden Igor Stravinsky shows up with bag of psilocybin
mushrooms and a chainsaw.... -- Jens

[Duane]

I was hoping for bike lanes...

[Doug Landau]

> > > What if I don't want to play with batteries?
> >
> > Then you're done with the battery light discussion and may move on to helmets.

> or carbon frames versus steel frames.

Stainless!!!
http://gearpatrol.com/2017/01/26/best-handmade-steel-bike-makers/

[Joerg]

I use my lights a great deal because they are on during the day as well
except on segregated bike paths.

Recharging is 2nd nature to me. Bike gets parked back in the garage,
li'l round connector gets plugged in, done. Sometimes I deliberately do
not charge past 8V until shortly before a ride. That improves battery
lifetime.

The real McCoy would be a worryfree system like in a car where it
recharges while riding. If I ever switch the road bike front wheel to
one with a hub dynamo I will do that. Right now it only has a bottle
dynamo, too much drag and it eats the left side wall of "modern" tires.
Power output of those is well above 3W at higher speeds if you provide
the proper electronics. I could go into that but it's nerdy tech stuff.
Essentially you need what is called a SEPIC or at least a buck converter
plus some sort of maximum power point tracking (MPPT) control for that
converter. Sounds more complicated than it really is but do not expect
the bicycle industry to deliver anything even remotely close anytime soon.

Realistically you could eke out 4-6W depending on you speed. That's not
enough to feed a MagicShine clone which wants 8W on high plus a watt or
so for the rear lights. And maybe another 1-2W for the MP3 player. Plus
the smart phone. And the electric razor :-)

In my case this would work nicely because I need the full 10W total only
on county roads and in city areas where car drivers tend to misbehave.
Else it drops to a net load of 4-5W or even much lower. So the dynamo
would recharge the watt-hours you used up on the county road. Once the
battery gets full it throttles back. Just like in car.

> I notice that a large number of the people in our group have flashing
> red rear lights and it isn't long before these batteries run down
> enough that the taillight even blinking is almost entirely
> unnoticeable. So I don't have much respect for battery power for a
> great deal of use.
>

Yep, that's a major nuisance. However ... one can power these lights off
a regular 8.4V Li-Ion battery or even a dynamo (after rectification) by
providing a 3V regulator. Small enough to fit where the two AAA cells
used to be.

If battery rear lights at least had a low-battery warning. Technically
that would be a piece of cake. But no ... nothing :-(

--
Regards, Joerg

http://www.analogconsultants.com/

[Joerg]

Nah, wood!

https://connorcycles.com/

[Jeff Liebermann]

<http://www.rayovacindustrial.com/Products/Lights/Bulbs/K13-2TB-Krypton-Bulb-for-4D-Flashlights.aspx>
Ray-0-Vac K13-2TB. Made for 4D cell lanterns. 6v 3.6 watts.
I couldn't find a 4 watt version. Most of what I found were 2.4 and
3.0 watt bulbs for bicycles.

[Jeff Liebermann]

On Mon, 6 Mar 2017 10:47:34 -0800 (PST), cycl...@gmail.com wrote:

>As a very occasional night rider I am interested in battery
>powered lights but I think that I was attempting to give
>a thought to a commuter that would use his light a great deal.

Do "occasional night riders" buy $150 headlights?

>I notice that a large number of the people in our group
>have flashing red rear lights and it isn't long before
>these batteries run down enough that the taillight even
>blinking is almost entirely unnoticeable. So I don't have
>much respect for battery power for a great deal of use.

Well, that's one of the advantages of a dynamo. You never have to
worry about a dead or discharged battery or remember to carry a spare
dead or discharged battery. (Yes, I've done that).

I think you'll find a fair number of riders in your group using low
cost rear flashers like this:
<http://www.ebay.com/itm/142066277090>
$0.97 gets you a two AAA batteries packaged inside a flasher (postage
included). That's about the same price as the batteries, assuming
that they're alkaline and not carbon-zinc. One of my friends says
that he picks them out of the trash at the end of club rides because
people just toss them instead of trying to figure out how to pry open
the case and change the battery. It wouldn't do them much good even
if it was easy to open, because the COB (chip on board) electronics,
buried under a blob of epoxy, will self destruct if you touch, bend,
or push on it. As for not noticing a failure, most club riders will
inform your if they see a problem.

I don't think it's fair to compare a $150 headlight, with a $0.97 tail
light. Others have mentioned various schemes to get more out of a
tail light. There are tail lights available or under design that have
motion sensors, LiIon battery, low battery indicator, solar charging,
USB charging, dynamo charging, wireless charging, side lighting,
programmable flashing, high brightness daylight mode, motion alarm,
automobile tailgating detection (via a bright headlight detector),
Bluegoof telemetry, and whatever else I forgot. Of course, they don't
cost $0.97.

[sms]

On 3/5/2017 5:26 PM, Jeff Liebermann wrote:
> On Sun, 5 Mar 2017 16:03:30 -0800 (PST), cycl...@gmail.com wrote:
>
>> Thanks Jeff. These however all appear to be battery powered
>> lights. We were sort of looking for lights that operated on
>> the hub dynamo of 6V 3W or the Globe dynamo of 12V 6W or
>> four times the power.
>
> Sorry, I thought you were still open to looking at battery powered
> lights. Here's what I fished out of my bookmark dumpster. No reviews
> and few tests, but some interesting dynamo graphs and numbers:
> <http://www.myra-simon.com/bike/dynotest.html>
> <http://pilom.com/BicycleElectronics/DynamoCircuits.htm>
> <http://www.eeweb.com/blog/extreme_circuits/power-mosfet-bridge-rectifier>
>
> This one is well worth reading (or skimming) and has quite a few test
> results:
> <http://swhs.home.xs4all.nl/fiets/tests/verlichting/index_en.html>
>
>> This is why the hub generator has so little drag.
>
> Well, let's do some arithmetic. If your dynamo is rated at 3 watts,
> and your lighting is rated at 70 lumens/watt, then the most you can
> perhaps deliver is 210 lumens. 6 watts will get perhaps 420 lumens.
> Usually, it's less as the losses accumulate. Rectification losses,
> optical losses, heat degradation, and connector losses all conspire to
> produce lower output.

WE passed 70 lumens per watt a long time
ago.<http://www.cree.com/LED-Components-and-Modules/Products/XLamp/Arrays-Directional/XLamp-MKR>.
And bicycle light manufacturers are early adopters of the latest LEDs.

A dynamo can produce more than 3 watts at high speeds. In the olden days
of incandescent dynamo lights there was protection circuitry to limit
the power to the bulb by cutting off the voltage over 6V. But these high
power LEDs can handle 15W so there's no need to limit the power.

This light <http://supernova-lights.com/en/supernova-e3-triple-2> claims
640 lumens at 4.5W. 4.5W is definitely possible from a nominal 3W
dynamo. It claims 800 lumens peak.

Note that his light, while sold in Germany, is not "road legal."
because, according to reviews, it doesn't suffer the problems of StVZO
lights, "It has a very broad light output that is closer to a floodlight
than a focused beam, and so doesn’t give the ‘tunnel’ effect of some of
the powerful battery-powered lights. This means it’s great for
illuminating branches and hazards above you and off to the side." As we
all know, the problem with StVZO legal lights are related to the
extremely focused spot beam. The best option, to avoid annoying others,
is to not use the highest settings when riding on narrow roads or paths.
You don't want endanger yourself by using sub-par StVZO lights unless
it's mandated by law.

[Jeff Liebermann]

On Mon, 6 Mar 2017 18:37:14 -0800, sms <scharf...@geemail.com>
wrote:

>WE passed 70 lumens per watt a long time
>ago.<http://www.cree.com/LED-Components-and-Modules/Products/XLamp/Arrays-Directional/XLamp-MKR>.
>And bicycle light manufacturers are early adopters of the latest LEDs.

I got burned badly when I specified an LED that was rated at 100
lumens/watt, and got something that was about 70 lumens/watt. If you
look at the Xlamp MK-R data sheet at:
<http://www.cree.com/~/media/Files/Cree/LED-Components-and-Modules/XLamp/Data-and-Binning/XLampMKR.pdf>
the footknots always says:
"Flux values @25 °C are calculated and for reference only."
I'm not sure exactly what that means, but from my limited experience,
it means that if you pulse the power to the LED with a very short duty
cycle, you might get something near the rated efficacy. If you run it
on DC, it won't even come close. Calculated also means that they
didn't bother to verify their own calculations with an integrating
sphere measurement.

Assuming 200 lumens/watt and 1000 lumens output, that would require 5
watts of input power. Looking at the same data sheet (Pg 15) the 6v
chart shows that 5w is 5.8v @ 0.85A. So far, so good. However, if we
look at the Relative Flux Vs. Current (tJ = 85 °C) graph on Pg 16, the
output is derated to 65% of 1000 lumens. Producing only 650 lumens.
Using those numbers, the efficacy is now:
650 lumens / 5 watts = 130 lumens/watt
Note that the 85C is the junction temp, not the case or heat sink
temp.

Then, there is matching LED chips. See Pg 20
"Performance Groups - Luminous Flux (Tj = 85 °C)"
where one can pick the chip output anywhere from about 515 to 1290
lumens. What is not obvious is that the efficiency also drops at the
lower output levels, resulting in even lower lumens/watt.

Then there's the loss in output due to reflectors and lenses and the
increase of input current from current regulator losses. I would
guess(tm) 15% loss of lumens to the optics, and 10% for the regulator
efficiency. So, we start with
650 lumens / 5 watts = 130 lumens/watt
and end up with:
650 * 0.85 / 5 * 1.1 = 553 / 5.5 = 100 lumens/watt

Can you see where this is going? In the end, the lumens/watt value
for the end product is the light output including all the optics,
divided by the power input as measured from the battery, and derated
by the chip junction temperature.

>A dynamo can produce more than 3 watts at high speeds.

I don't ride at high speeds. I'm slowly converting one of my machines
to a "comfort" bicycle.

>In the olden days
>of incandescent dynamo lights there was protection circuitry to limit
>the power to the bulb by cutting off the voltage over 6V. But these high
>power LEDs can handle 15W so there's no need to limit the power.

Yep. So why do many dynamos still use the increased inductive
reactance at higher speeds (and higher frequencies) to provide this
voltage limiting? It would be easy enough to reduce the winding
inductance and allow the voltage to increase linearly instead of
flat-topping. The manufacturer might be afraid of blowing something
up with too much voltage at high speeds.

>This light <http://supernova-lights.com/en/supernova-e3-triple-2> claims
>640 lumens at 4.5W. 4.5W is definitely possible from a nominal 3W
>dynamo. It claims 800 lumens peak.

640 lumens / 4.5 watts = 142 lumens/watt measured "warm".
If they start out with a 200 lumens/wall LED, that might be possible.
Ok, I stand corrected, but I'm also suspicious.

I couldn't find any test reports or method used on the Supernova site.
I did find this test of the M99 model:
<http://supernova-lights.com/en/blog/supernova-blog-1/post/first-test-performance-supernova-m99-pro-br-36>
1100 lumens / 16 watts = 68.7 lumens/watt. Hmmm...

[Frank Krygowski]

On 3/6/2017 4:33 PM, Joerg wrote:
>
> The real McCoy would be a worryfree system like in a car where it
> recharges while riding. If I ever switch the road bike front wheel to
> one with a hub dynamo I will do that. Right now it only has a bottle
> dynamo, too much drag and it eats the left side wall of "modern" tires.

I've done well with a bottle dynamo whose drive wheel has an added
circumferential groove to hold a thick O-ring. That O-ring runs on the
rim's braking surface, not on the tire. Zero tire wear, and it runs
very smoothly. I've experienced no slipping - but it's not been tested
in the rain.


--
- Frank Krygowski

[Frank Krygowski]

On 3/6/2017 1:47 PM, cycl...@gmail.com wrote:
>
> I notice that a large number of the people in our group have flashing red rear lights and it isn't long before these batteries run down enough that the taillight even blinking is almost entirely unnoticeable. So I don't have much respect for battery power for a great deal of use.

When the first twinkling LED taillights (by Vistalight) came out in the
1990s, people were very impressed by how visible they made a bike.
Bikes were visible up to half a mile away, and AA batteries in those
units last months.

Since then, "safety inflation" has proclaimed that they're insufficient
because they're too dim. Now you need a taillight so bright that it
blinds following riders. Of course those consume much more electricity.

--
- Frank Krygowski

[Jeff Liebermann]

On Mon, 6 Mar 2017 16:57:41 +1100, James <james.e...@gmail.com>
wrote:

>What if I don't want to play with batteries?

Then play with calcium carbide (produces acetylene gas) instead:
<https://www.google.com/search?q=acetylene+bicycle+lamp&tbm=isch>

[Frank Krygowski]

On 3/6/2017 9:37 PM, sms wrote:
>
> This light <http://supernova-lights.com/en/supernova-e3-triple-2> claims
> 640 lumens at 4.5W. 4.5W is definitely possible from a nominal 3W
> dynamo. It claims 800 lumens peak.
>
> Note that his light, while sold in Germany, is not "road legal."
> because, according to reviews, it doesn't suffer the problems of StVZO
> lights, "It has a very broad light output that is closer to a floodlight
> than a focused beam, and so doesn’t give the ‘tunnel’ effect of some of
> the powerful battery-powered lights. This means it’s great for
> illuminating branches and hazards above you and off to the side." As we
> all know, the problem with StVZO legal lights are related to the
> extremely focused spot beam.

Here's an example of an StVZO headlamp (2013 model) with the "extremely
focused spot beam" the Scharf complains about.
http://peterwhitecycles.com/images/products/Lights/sch-edelux-II-800.jpg

See that tiny spot? ;-)


--
- Frank Krygowski

[Jeff Liebermann]

On Mon, 6 Mar 2017 23:11:26 -0500, Frank Krygowski
<frkr...@sbcglobal.net> wrote:

>Here's an example of an StVZO headlamp (2013 model) with the "extremely
>focused spot beam" the Scharf complains about.
>http://peterwhitecycles.com/images/products/Lights/sch-edelux-II-800.jpg
>
>See that tiny spot? ;-)

Here's the same photo with brightness converted to pseudo colors:
<http://802.11junk.com/jeffl/pics/bicycles/Front-Light-False-Color/sch-edelux-II-800.jpg>
No obvious hot spot.

[DATAKOLL MARINE RESEARCH]

never experiencing dyna lighting, the White photo bears no relation to anything I've read here.

I aaside the cycle is moving at 35 mph.

[lou.h...@gmail.com]

That is the headlight I use and it looks exactly the same on a pitch dark street. So again I don't understand why people find this amount of light insufficient.

Lou

[John B.]

On Mon, 6 Mar 2017 11:15:54 -0800 (PST), jbeattie <jbeat...@msn.com>
wrote:

I thought that chain-lube was next on the agenda?
--
Cheers,

John B.

[John B.]

On Mon, 06 Mar 2017 20:10:21 -0800, Jeff Liebermann <je...@cruzio.com>
wrote:

>On Mon, 6 Mar 2017 16:57:41 +1100, James <james.e...@gmail.com>
>wrote:
>
>>What if I don't want to play with batteries?
>
>Then play with calcium carbide (produces acetylene gas) instead:
><https://www.google.com/search?q=acetylene+bicycle+lamp&tbm=isch>

Ahem! I don't think you should suggest acetylene gas devices to some
of the folks here. After all the safe limit for acetylene gas is 15
psi, above which it tends to go BOOM! :-)

(but maybe if you wear a helmet and have a bright light... :-)
--
Cheers,

John B.

[Joerg]

May main issue isn't rain but mud. Often the Soubitez bottle dynamo on
my road bike mutates into a clump of drying clay.

Back in Europe slush and ice was the main issue. Typically on a night
ride back home when a cold front rushed in. The slush accumulated at the
dynamo, gradually froze up there and at some point ... phseeeee ... no
more light on our bikes except on mine because that had a battery.

[Jeff Liebermann]

On Tue, 07 Mar 2017 20:00:47 +0700, John B. <sloc...@gmail.com>
wrote:

>On Mon, 06 Mar 2017 20:10:21 -0800, Jeff Liebermann <je...@cruzio.com>
>wrote:
>
>>On Mon, 6 Mar 2017 16:57:41 +1100, James <james.e...@gmail.com>
>>wrote:
>>
>>>What if I don't want to play with batteries?
>>
>>Then play with calcium carbide (produces acetylene gas) instead:
>><https://www.google.com/search?q=acetylene+bicycle+lamp&tbm=isch>

>Ahem! I don't think you should suggest acetylene gas devices to some
>of the folks here. After all the safe limit for acetylene gas is 15
>psi, above which it tends to go BOOM! :-)

I once found a patent for an acetylene lantern design that used the
heated gas pressure from the burning acetylene to pressurize a reed
and thus act as a horn. I don't recall if it had a built in red tail
light.

What keeps an acetylene lantern from blowing up and ruining a ride is
that the drip of water into the calcium carbide chamber is regulated
by the back pressure produced by the reaction. No water means no gas
is produced. It's a gravity fed affair, that's quite reliable and
should never raise the internal pressure anywhere near 15 psig.

>(but maybe if you wear a helmet and have a bright light... :-)

The light isn't for me. It's for James who wants an alternative to
changing batteries. I solved my lighting problem long ago:
<http://802.11junk.com/jeffl/pics/bicycles/slides/bicycle-flashlight.html>

The big problem with an acetylene bicycle lantern is that a typical
lantern only delivers about 30 to 50 lumens (my measurements).

If you need a project, build an acetylene lamp that screws into an
aluminum water bottle.
<http://www.4bobandbob.com/pages/pics/PremierDia.gif>

[Sepp Ruf]

lou.holtman wrote:
> On Tuesday, March 7, 2017 at 5:11:29 AM UTC+1, Frank Krygowski wrote:

>> http://peterwhitecycles.com/images/products/Lights/sch-edelux-II-800.jpg

Still too much chroma, but a more realistic looking comparison than the
aperiodical illumination of Mr. White's rustic driveway:
<http://baslerbikes.de/index.php/baslerbikes-2-Scheinwerfervergleich-2013-november.html>

> That is the headlight I use and it looks exactly the same on a pitch dark street.

Must be an extra-bright asphalt mix they use in NL - or simply a layer of sand.


--
Merkel's new StVZO aiming instructions: crescent just below line H-H
<http://i.dailymail.co.uk/i/pix/2016/08/08/08/36FC213600000578-0-image-a-2_1470641631742.jpg>

[James]

On 07/03/17 04:22, Jeff Liebermann wrote:
> On Mon, 6 Mar 2017 17:04:13 +1100, James <james.e...@gmail.com>
> wrote:
>
>> On 06/03/17 12:26, Jeff Liebermann wrote:
>>>

>>> Well, let's do some arithmetic. If your dynamo is rated at 3 watts,
>>> and your lighting is rated at 70 lumens/watt, then the most you can
>>> perhaps deliver is 210 lumens. 6 watts will get perhaps 420 lumens.
>>> Usually, it's less as the losses accumulate. Rectification losses,
>>> optical losses, heat degradation, and connector losses all conspire to
>>> produce lower output.
>

>> We know that a 3W dynamo is quite capable of delivering more power than
>> 3W, once the bicycle speed increases. 6W from a 3W dynamo is quite
>> achievable, and the retardation torque drops off as speed increases too.
>
> Maybe:
> <http://www.myra-simon.com/bike/dynotest.html>
> See "Electrical Output" graph.
>
> Kinda looks like all of them will sorta deliver 2.5 watts before the
> core saturates (to provide some level of voltage regulation). Further
> down the page is a "Low Speed Power" graph, which shows that most can
> produce 2.0-2.5 watts at 10km/hr. One could assume that the dynamo
> will deliver 4.0 watts, but that would require buying one of the few
> better (hub) dynamos listed, and riding at 25-30km/hr (15-19mph).
>
> If I were designing or sizing a lighting system suitable for my slow
> style of "cruising", I would use the worst case 10km/hr (6mph) and 2.0
> watt figures.
>
>

Back to electrical engineering school for you, Jeff.

--
JS

[John B.]

On Tue, 07 Mar 2017 10:38:38 -0800, Jeff Liebermann <je...@cruzio.com>

wrote:

>On Tue, 07 Mar 2017 20:00:47 +0700, John B. <sloc...@gmail.com>
>wrote:
>
>>On Mon, 06 Mar 2017 20:10:21 -0800, Jeff Liebermann <je...@cruzio.com>
>>wrote:
>>
>>>On Mon, 6 Mar 2017 16:57:41 +1100, James <james.e...@gmail.com>
>>>wrote:
>>>
>>>>What if I don't want to play with batteries?
>>>
>>>Then play with calcium carbide (produces acetylene gas) instead:
>>><https://www.google.com/search?q=acetylene+bicycle+lamp&tbm=isch>
>
>>Ahem! I don't think you should suggest acetylene gas devices to some
>>of the folks here. After all the safe limit for acetylene gas is 15
>>psi, above which it tends to go BOOM! :-)
>
>I once found a patent for an acetylene lantern design that used the
>heated gas pressure from the burning acetylene to pressurize a reed
>and thus act as a horn. I don't recall if it had a built in red tail
>light.
>
>What keeps an acetylene lantern from blowing up and ruining a ride is
>that the drip of water into the calcium carbide chamber is regulated
>by the back pressure produced by the reaction. No water means no gas
>is produced. It's a gravity fed affair, that's quite reliable and
>should never raise the internal pressure anywhere near 15 psig.
>

Well, yes, that sounds like a very good idea, but.... Over here you
can still buy an "acetylene generator" used to provide acetylene gas
for a welding torch. These use the same system "no water, no gas" that
the lamps do. But unfortunately over years of use they get rusty,
dusty, corroded or just clogged up and every once in a while they do
explode. Usually with loss of life.

>>(but maybe if you wear a helmet and have a bright light... :-)
>
>The light isn't for me. It's for James who wants an alternative to
>changing batteries. I solved my lighting problem long ago:
><http://802.11junk.com/jeffl/pics/bicycles/slides/bicycle-flashlight.html>
>

:-} I solvd my problems using a much simpler solution... don't ride at night :-{

>The big problem with an acetylene bicycle lantern is that a typical
>lantern only delivers about 30 to 50 lumens (my measurements).
>
>If you need a project, build an acetylene lamp that screws into an
>aluminum water bottle.
><http://www.4bobandbob.com/pages/pics/PremierDia.gif>

Don't need a project. But back when I was shooting on A.F. pistol
teams we used "carbide lamps" to blacken the sights. Very simple
lights with a canister for the carbide and a igniter incorporated in
the reflector that you could flick with your thumb. Spit in the
carbide receptacle, hold your hand over the reflector for a second or
two and flick the igniter. POP (sometimes BANG) and you had a nice
"rich" flame to blacken the sights.

Quite a bright light too. I've used one to look for things in dark
corners and they seem to give off sufficient light. Much better than
my old Japanese bike with the bottle generator and the incandescent
light bulb anyway. And, of course, you didn't have to pedal them to
have lights :-)
--
Cheers,

John B.

[James]

On 07/03/17 06:15, jbeattie wrote:
> On Sunday, March 5, 2017 at 9:57:44 PM UTC-8, James wrote:
>> On 06/03/17 10:22, Barry Beams wrote:
>>
>>>
>>> Burn time: What if you had five or ten hours battery time at your
>>> generator's brightness? My Oculus gives at least that much
>>> brightness, and a quickly field replaceable battery so you can put in
>>> a fresh battery. Other rechargeables leave you out of light and out
>>> of luck when the battery drains. Oculus also comes with a spare
>>> battery included.
>>>
>>

>> What if I don't want to play with batteries?
>

> Then you're done with the battery light discussion and may move on to helmets.
>

Now that you mention it...

I don't like putting sun screen on the top of my head because in the
heat and humidity I sweat a lot and it tends to run down into my eyes
and stings most painfully with sun screen mixed in.

So my foam hat has big ventilation holes that let the sun light through
to my scalp.

If I was allowed to ride without a foam hat I could keep the sun off my
scalp with a cloth cap, but that's not an option in this country.

If I develop a skin cancer on the top of my head, I shall seek to sue
the government, for their law makes adequate sun protection with
sufficient ventilation near on impossible.

--
JS

[James]

On 07/03/17 18:58, lou.h...@gmail.com wrote:
> On Tuesday, March 7, 2017 at 5:11:29 AM UTC+1, Frank Krygowski
> wrote:
>> On 3/6/2017 9:37 PM, sms wrote:
>>>
>>> This light <http://supernova-lights.com/en/supernova-e3-triple-2>
>>> claims 640 lumens at 4.5W. 4.5W is definitely possible from a
>>> nominal 3W dynamo. It claims 800 lumens peak.
>>>
>>> Note that his light, while sold in Germany, is not "road legal."
>>> because, according to reviews, it doesn't suffer the problems of
>>> StVZO lights, "It has a very broad light output that is closer to
>>> a floodlight than a focused beam, and so doesn’t give the
>>> ‘tunnel’ effect of some of the powerful battery-powered lights.
>>> This means it’s great for illuminating branches and hazards above
>>> you and off to the side." As we all know, the problem with StVZO
>>> legal lights are related to the extremely focused spot beam.
>>
>> Here's an example of an StVZO headlamp (2013 model) with the
>> "extremely focused spot beam" the Scharf complains about.
>> http://peterwhitecycles.com/images/products/Lights/sch-edelux-II-800.jpg
>>
>>
>>See that tiny spot? ;-)
>>
>

> That is the headlight I use and it looks exactly the same on a pitch
> dark street. So again I don't understand why people find this amount
> of light insufficient.
>

But when you're riding home through the local forest MTB paths, and it's
snowing and there are overhanging branches and a Joerg or SMS comes the
other way with a blinding 1200lm torch beam.....

You might not see that salmon swimming across the path!

--
JS

[James]

On 07/03/17 11:50, Jeff Liebermann wrote:
> On Mon, 6 Mar 2017 20:10:38 +0000 (UTC), David Scheidt
> <dsch...@panix.com> wrote:
>
>> Frank Krygowski <frkr...@gmail.com> wrote:
>> :On Monday, March 6, 2017 at 1:37:23 PM UTC-5, AMuzi wrote:
>> :> I don't know about currents but 6V 4W bulbs for standard
>> :> dynamo systems have been around for twenty years and some
>> :> customers like them. I don't know if the dynamo drag is
>> :> noticeably greater.
>
>> :6V 4W? I'm aware of 6V 3W bulbs, which are (or were) used mostly with bottle
>> :dyno systems when driving a headlamp but no taillamp. They were an alternative
>> :to 2.4 W in front and 0.6W in back.
>
>> :I'm not aware of any common use of 6V 4W bulbs.
>
>> It's a standard lantern size.
>
> <http://www.rayovacindustrial.com/Products/Lights/Bulbs/K13-2TB-Krypton-Bulb-for-4D-Flashlights.aspx>
> Ray-0-Vac K13-2TB. Made for 4D cell lanterns. 6v 3.6 watts.
> I couldn't find a 4 watt version. Most of what I found were 2.4 and
> 3.0 watt bulbs for bicycles.
>

A 6V 3W dynamo will easily power a 12V 6W bulb, but at higher speed.

In the same way, it has been tried and tested to install two 6V 3W
headlights, and a switch that can bypass one light, or connect the two
in series.

--
JS

[Frank Krygowski]

On 3/7/2017 3:42 PM, Sepp Ruf wrote:
> lou.holtman wrote:
>> On Tuesday, March 7, 2017 at 5:11:29 AM UTC+1, Frank Krygowski wrote:
>
>>> http://peterwhitecycles.com/images/products/Lights/sch-edelux-II-800.jpg
>
> Still too much chroma, but a more realistic looking comparison than the
> aperiodical illumination of Mr. White's rustic driveway:
> <http://baslerbikes.de/index.php/baslerbikes-2-Scheinwerfervergleich-2013-november.html>
>
>> That is the headlight I use and it looks exactly the same on a pitch dark street.
>
> Must be an extra-bright asphalt mix they use in NL - or simply a layer of sand.

I've noticed that the asphalt does lighten in color somewhat as it ages.
And I've noticed that dark road surfaces are not as visible in the
headlight beam. This is true even with car headlight beams; the dark
surface obviously reflects less light back to the operator's eyes.
(That's probably covered in the definition of "dark.")

This adds to the complexity of producing realistic screen shots of
headlight beams. And it's already complex enough, because different
camera exposure settings, different focal lengths, different lighting
environments, etc. make one website's beam shots look quite different
from another. Even if all testers used the same parameters, it might
not match what the human eye perceives.

If one were to develop an ASTM standard for headlight screen shots, all
those and other factors would have to be uniformly controlled.

Sounds like a good project for someone's masters' thesis.


--
- Frank Krygowski

[Frank Krygowski]

Now, now, now! This person in Melbourne
https://pricetags.files.wordpress.com/2017/02/sun-bike.jpg?w=560
proves that it's a simple matter to have sun protection, yet to have the
foam hat close enough to one's head for it's magic to be effective.

;-)

BTW, I've seen the same trick used in America. So I've learned that any
bike facility is a good bike facility, and a helmet anywhere near your
head will save your life.


--
- Frank Krygowski

[jbeattie]

http://www.aerotechdesigns.com/cycling-beanie-sun-protector.html Reasonable accommodation for the hair-differently-abled. Not recommended for wearing in Kansas, Washington or any other US state where one could be mistaken for a Sikh.

-- Jay Beattie.

[AMuzi]

Choose you fashion. The Ancients rode with a cabbage leaf on
the hot Tour days:

http://2.bp.blogspot.com/-ZzoNWiNl84I/UVHDa9ym3qI/AAAAAAAAOpY/ZzKnz6AdzF4/s400/cabbagesjpg.jpg

--
Andrew Muzi
<www.yellowjersey.org/>
Open every day since 1 April, 1971

[Frank Krygowski]

On 3/6/2017 2:12 AM, DATAKOLL MARINE RESEARCH wrote:
> Assumptions or measured ?

I forgot to respond to that question.

I've measured dynamo torque vs. speed. As James says, the resistance
torque of a dyno decreases as speed increases. It doesn't decrease as
much as speed increases, however, so the power required still increases
with speed.

Example: Soubitez roller dynamo

Speed (mph) 6 12 18 24
Torque (N*mm) 26.4 22.6 18.1 14.3 with 12 Ohm load
Torque (N*mm) 22.6 23.4 19.6 15.1 with 24 Ohm load

I found similar behavior with other dynamos.

With an open circuit, drive torque did increase with road speed.

--
- Frank Krygowski

[Sir Ridesalot]

On Tuesday, March 7, 2017 at 7:09:21 PM UTC-5, James wrote:
Snipped

> If I was allowed to ride without a foam hat I could keep the sun off my
> scalp with a cloth cap, but that's not an option in this country.
>
> If I develop a skin cancer on the top of my head, I shall seek to sue
> the government, for their law makes adequate sun protection with
> sufficient ventilation near on impossible.
>
> --
> JS

Just curious, does the legislation specifically state that your helmet must be worn on your head? Or does it simply state that a helmet must be worn? On a long ride a few years ago it got extremely hot so I slung mu helmet over my shoulder on a long srtrap. the organizers at a rest stop saw it and said i must wear the helmet on my head. I showed them the waiver and also showed them that it only stated that I promised to wear a helmet but there was no mention of wear I had to wear the helmet. Perhaps your local legislation has a similar loophole?

Cheers

[Frank Krygowski]

Years ago, a friend and I drove support for a charity ride. The ride
was not organized by our club, but our club volunteered to help out.

Anyway, the ride had a "helmets required" policy. Late in the day, we
came upon a guy, probably in his 60s, riding along with a rider number,
but with his helmet strapped to his bike's back rack. He probably took
it off because of the heat.

My friend said "We've got to stop him and make him put his helmet on!"

I said "How? Will we tell him he's not allowed to ride on this public
road? Let him alone; he's old enough to know what he's doing." And I
refused to slow or stop the car I was driving.

BTW, that was so long ago, I still sort of believed in helmets back then.

--
- Frank Krygowski

[John B.]

On Wed, 8 Mar 2017 11:09:16 +1100, James <james.e...@gmail.com>
wrote:

Such a problem. You could use a "do rag", as they call it in America;
or a Balaclava hood such as we have here, made of very stretchy fabric
and can be worn as a skull cap or pulled down to shield the face and
neck both worn under the helmet of course.
See: http://tinyurl.com/hquplny

And apparently a new innovation I see the ladies wearing this year. A
sort of poke bonnet with at least a six inch deep brim. Again, of
course, worn under the helmet and not only covering he crown of the
head but keeps the face white also :-)

Or perhaps that ultimate in protection for the Cyclist who is ultra
worried about sun protection::
http://tinyurl.com/zf8uexq
--
Cheers,

John B.

[Duane]

On 07/03/2017 7:09 PM, James wrote:
<snip>

> Now that you mention it...
>
> I don't like putting sun screen on the top of my head because in the
> heat and humidity I sweat a lot and it tends to run down into my eyes
> and stings most painfully with sun screen mixed in.
>
> So my foam hat has big ventilation holes that let the sun light through
> to my scalp.
>
> If I was allowed to ride without a foam hat I could keep the sun off my
> scalp with a cloth cap, but that's not an option in this country.
>
> If I develop a skin cancer on the top of my head, I shall seek to sue
> the government, for their law makes adequate sun protection with
> sufficient ventilation near on impossible.
>

When it's too hot to ride with my cycling cap under my helmet, I use one
of these:
https://www.mec.ca/en/product/5046-050/Summer-Skullcap

Probably a better idea than skin cancer.

[jbeattie]

Why would torque increase with speed with an open circuit?

-- Jay Beattie.

[cycl...@gmail.com]

On Monday, March 6, 2017 at 1:04:03 PM UTC-8, Doug Landau wrote:
> > > > What if I don't want to play with batteries?
> > >
> > > Then you're done with the battery light discussion and may move on to helmets.
>

> > or carbon frames versus steel frames.
>
>
> Stainless!!!
> http://gearpatrol.com/2017/01/26/best-handmade-steel-bike-makers/

Can't do it. These people who are riding old rusty 6 speeds are telling me that carbon fiber is as safe as steel.

[jbeattie]

I clearly have a defective hub or light or something -- or else I need a pitch dark forest road with reflective gravel.

I couldn't see a godamn thing riding home last night -- again in a rain storm, with a death grip on the bars because I was getting blown over. Wet pavement swallows light, but the real problem is all the point-source light pollution -- blinding car headlights when riding in wrong-side bike facilities. I actually yelled at some guy on a bike with a mega-flasher. Pop, pop, pop go the retinas. WTF? How could anyone possibly think that was O.K.? This was in a wrong-side two-way bike facility, so I'm staring into car lights on the left and bike lights on the right. Maybe I should get some of those polarized night-driving glasses.

-- Jay Beattie.

[Duane]

I hear your pain. I can't take these guys with they're freaking search
beams on their bikes. Why is it not ok for cars to come up to you on a
road with their high beams on but it's ok for a cyclist to blind
everyone looking at them? And WTF is the point of high intensity (what
you call mega) flashers at night? I've had near crashes due to both of
these types of idiots.

[Sir Ridesalot]

What you need are flip up/flip down sunglass lenses to wear over glasses or clear cycling goggles. They do help a lot. I'd also like to be able to mount heat seeking missiles so that I could blow those blinding lights up. However I do realize that'd be illegal. Like I've mentioned before, there are times when i have to slam on my brakes becasue some idiot with super bright lights steady or strobe blinds me to the pointI can not see where the road or trail is and a stop is warranted lest I ride off either.

Hmmm, I wonder if a good size flip up polycarbonate mirror on the front of my bike could/would reflect tht annoyingly dangerous over bright light back atthe rider using it? Letthem know what it's like to be blinded at night.

Cheers

[Frank Krygowski]

I think because losses are inevitable. In addition to bearing drag,
there's a certain amount of loss due to eddy currents in the dynamo's
components, and there's windage loss churning the air around inside the
thing. Bottle dynamos spin at surprisingly high speed, BTW. 5000 rpm
would not be unusual.

--
- Frank Krygowski

[Sepp Ruf]

jbeattie wrote:
> On Monday, March 6, 2017 at 11:58:20 PM UTC-8, lou.h...@gmail.com wrote:
>> On Tuesday, March 7, 2017 at 5:11:29 AM UTC+1, Frank Krygowski wrote:

>>> http://peterwhitecycles.com/images/products/Lights/sch-edelux-II-800.jpg

>> That is the headlight I use and it looks exactly the same on a pitch dark
>> street.

> I clearly have a defective hub or light or something -- or else I need a
> pitch dark forest road with reflective gravel.

The hub is not likely to gradually fail. I've read much whining from you
about the bulbous Luxos B. Face it, whoever recommended it as a sole lamp
for rainy, high-traffic environments and twisty trails -- he was wrong.

Before dumping the Luxos altogether or converting it into a 3 amp LED host
fed by battery power, one could try a conservative lamp mod with a more
efficient LED that enhances output to 100 lux, as one guy claims,
http://laempie.de/?Fahrradlampen-Modifikation
But if your lamp really does 70 lux as it should, you might not be able to
appreciate the difference.

> I couldn't see a godamn thing riding home last night -- again in a rain
> storm, with a death grip on the bars because I was getting blown over. Wet
> pavement swallows light, but the real problem is all the point-source
> light pollution -- blinding car headlights when riding in wrong-side bike
> facilities. I actually yelled at some guy on a bike with a mega-flasher.
> Pop, pop, pop go the retinas. WTF? How could anyone possibly think that
> was O.K.? This was in a wrong-side two-way bike facility, so I'm staring
> into car lights on the left and bike lights on the right. Maybe I should
> get some of those polarized night-driving glasses.

(See what you get when well-meaning activists demand special bike "facilities?")

What eyewear are you currently using in nightly traffic?
Years past last appointment at eye doc's?
Who would legitimately be selling "polarized night-driving" glasses? Don't
buy anything there!

Using 3000-3500K LEDs yourself, and blocking most of the enemy HID and LED
blue with light yellow tinted, AR-enhanced eyewear that blocks <450nm, but
passes 490>nm, is a better plan. If you want to spend more for less effect,
consider getting the clear-looking Zeiss DriveSafe or similar glasses.

[Frank Krygowski]

Two nights ago, I was driving home from a distant small town on a rainy
night. I noticed that, as I've mentioned, I couldn't really see my
car's headlight beams on the wet road. Instead, the road was visible
because its smooth wet surface reflected all the other light sources -
car headlights, car taillights, street lights, porch lights, etc.

I don't think there's any way to make a vehicle's headlight beams
prominent on such a wet smooth surface without scorching everyone else's
eyes.

It's like pointing a flashlight so it glances off a mirror. The surface
of a mirror doesn't light up; at best, if there's any dust on that
surface, you'll notice that. Grab a flashlight and try it.


--
- Frank Krygowski

[sms]

On 3/6/2017 7:41 PM, Jeff Liebermann wrote:

> I couldn't find any test reports or method used on the Supernova site.
> I did find this test of the M99 model:
> <http://supernova-lights.com/en/blog/supernova-blog-1/post/first-test-performance-supernova-m99-pro-br-36>
> 1100 lumens / 16 watts = 68.7 lumens/watt. Hmmm...

No need to use the most expensive LEDs on a battery powered light.

[sms]

On 3/6/2017 6:27 PM, Jeff Liebermann wrote:
> On Mon, 6 Mar 2017 10:47:34 -0800 (PST), cycl...@gmail.com wrote:
>
>> As a very occasional night rider I am interested in battery
>> powered lights but I think that I was attempting to give
>> a thought to a commuter that would use his light a great deal.
>
> Do "occasional night riders" buy $150 headlights?
>
>> I notice that a large number of the people in our group
>> have flashing red rear lights and it isn't long before
>> these batteries run down enough that the taillight even
>> blinking is almost entirely unnoticeable. So I don't have
>> much respect for battery power for a great deal of use.
>
> Well, that's one of the advantages of a dynamo. You never have to
> worry about a dead or discharged battery or remember to carry a spare
> dead or discharged battery. (Yes, I've done that).
>
> I think you'll find a fair number of riders in your group using low
> cost rear flashers like this:
> <http://www.ebay.com/itm/142066277090>
> $0.97 gets you a two AAA batteries packaged inside a flasher (postage
> included). That's about the same price as the batteries, assuming
> that they're alkaline and not carbon-zinc. One of my friends says
> that he picks them out of the trash at the end of club rides because
> people just toss them instead of trying to figure out how to pry open
> the case and change the battery. It wouldn't do them much good even
> if it was easy to open, because the COB (chip on board) electronics,
> buried under a blob of epoxy, will self destruct if you touch, bend,
> or push on it. As for not noticing a failure, most club riders will
> inform your if they see a problem.

You used to be able to get 2xAA powered flashers, but they weren't 97¢

The best rear light was made by CatEye, and discontinued of course, but
still available via Amazon: <https://www.amazon.com/dp/B00MQPEW10>.
These ran for much much longer than AAA powered rear lights.

The trend now is toward smaller, USB rechargeable tail lights. No reason
you could not charge these via a dynamo.

[sms]

On 3/6/2017 9:22 AM, Jeff Liebermann wrote:

> Kinda looks like all of them will sorta deliver 2.5 watts before the
> core saturates (to provide some level of voltage regulation). Further
> down the page is a "Low Speed Power" graph, which shows that most can
> produce 2.0-2.5 watts at 10km/hr. One could assume that the dynamo
> will deliver 4.0 watts, but that would require buying one of the few
> better (hub) dynamos listed, and riding at 25-30km/hr (15-19mph).
>
> If I were designing or sizing a lighting system suitable for my slow
> style of "cruising", I would use the worst case 10km/hr (6mph) and 2.0
> watt figures.

You've touched on one of the reasons why dynamo lights haven't caught on
in the U.S..

I wish that it were possible for inexpensive, dynamo powered lights to
provide adequate illumination for commuting, but it isn't. I recognize
that few people can afford nearly $500 for a hub dynamo wheel and a
SuperNova E3 Triple 2. For commuting, where there is no problem
charging batteries every night, a high power LED set-up is more
economical and provides better illumination. It's hard enough getting
people to spend even $25 on a bicycle light, getting them fork out $500
for a dynamo wheel and a decent dynamo light would be damn near impossible.

[James]

On 08/03/17 14:03, Sir Ridesalot wrote:
> On Tuesday, March 7, 2017 at 7:09:21 PM UTC-5, James wrote: Snipped
>> If I was allowed to ride without a foam hat I could keep the sun
>> off my scalp with a cloth cap, but that's not an option in this
>> country.
>>
>> If I develop a skin cancer on the top of my head, I shall seek to
>> sue the government, for their law makes adequate sun protection
>> with sufficient ventilation near on impossible.
>>
>

> Just curious, does the legislation specifically state that your
> helmet must be worn on your head? Or does it simply state that a
> helmet must be worn? On a long ride a few years ago it got extremely
> hot so I slung mu helmet over my shoulder on a long srtrap. the
> organizers at a rest stop saw it and said i must wear the helmet on
> my head. I showed them the waiver and also showed them that it only
> stated that I promised to wear a helmet but there was no mention of
> wear I had to wear the helmet. Perhaps your local legislation has a
> similar loophole?
>

"The rider of a bicycle must wear an approved bicycle helmet securely
fitted and fastened on the rider’s head, unless the rider is exempt from
wearing a bicycle helmet under another law of this jurisdiction."

I don't have an exemption.

--
JS

[James]

How hot does it get where you are?

--
JS

[Sir Ridesalot]

Bummer that your law is so specific.

Where I am in Ontario, Canada it can get in the 90s F and have a humidity index of 90 - 100% at times. That's hard on the system because you sweat a LOT but it doesn't evaporate but can run down into your eyes where it can burn as if it's an acid.

Cheers

[James]

It would be interesting to know for a hub dynamo over regular hub.
According to SP, about 1W at 30km/h with the light off. From previous
research into hubs with sealed bearings, I think I recall that each
bearing contributes about 0.5W at 50km/h, so about 0.6W at 30km/h for 2
bearings in a regular hub.

It's not like 0.4W is easy to detect by the rider.

--
JS

[James]

On 10/03/17 17:02, Sir Ridesalot wrote:

>
> Bummer that your law is so specific.
>
> Where I am in Ontario, Canada it can get in the 90s F and have a
> humidity index of 90 - 100% at times. That's hard on the system
> because you sweat a LOT but it doesn't evaporate but can run down
> into your eyes where it can burn as if it's an acid.
>
> Cheers
>

We regularly get summertime temperatures over 100F here, and can be that
humid as well.

Good for rapid dehydration, hallucination, etc..

--
JS

[Sir Ridesalot]

Saw a guy one year on the organized ride here. After 100 kms he was at the ride end and was in agony from severe cramping. Ended up in ER and last I hear was he'd had 4 IV bags pumped into him. I've heard from professional medical personnel that severe cramping can actually pull ligaments or tendons away from the bones or muscles. Yopu really do not want to get that dehydrated.

Cheers

[Duane]

Here in Quebec 32-34C. Not that bad as it isn't constant and not that
humid. In New Orleans where I'm from, ~38 - 40C is not unusual. And
always humid.

I imagine it's hotter where you are but some of these UPF materials work
pretty well. Light and cool. Not as spiffy as my cycling caps though.

[jbeattie]

On Monday, March 6, 2017 at 1:33:10 PM UTC-8, Joerg wrote:
> On 2017-03-06 10:47, cycl...@gmail.com wrote:
> > On Sunday, March 5, 2017 at 5:26:18 PM UTC-8, Jeff Liebermann wrote:
> >> On Sun, 5 Mar 2017 16:03:30 -0800 (PST), cycl...@gmail.com
> >> wrote:
> >>
> >>> Thanks Jeff. These however all appear to be battery powered
> >>> lights. We were sort of looking for lights that operated on the
> >>> hub dynamo of 6V 3W or the Globe dynamo of 12V 6W or four times
> >>> the power.
> >>
> >> Sorry, I thought you were still open to looking at battery powered
> >> lights. Here's what I fished out of my bookmark dumpster. No
> >> reviews and few tests, but some interesting dynamo graphs and
> >> numbers: <http://www.myra-simon.com/bike/dynotest.html>
> >> <http://pilom.com/BicycleElectronics/DynamoCircuits.htm>
> >> <http://www.eeweb.com/blog/extreme_circuits/power-mosfet-bridge-rectifier>
> >>
> >>
> >>
> This one is well worth reading (or skimming) and has quite a few test
> >> results:
> >> <http://swhs.home.xs4all.nl/fiets/tests/verlichting/index_en.html>
> >>
> >>> This is why the hub generator has so little drag.
> >>
> >> Well, let's do some arithmetic. If your dynamo is rated at 3
> >> watts, and your lighting is rated at 70 lumens/watt, then the most
> >> you can perhaps deliver is 210 lumens. 6 watts will get perhaps
> >> 420 lumens. Usually, it's less as the losses accumulate.
> >> Rectification losses, optical losses, heat degradation, and
> >> connector losses all conspire to produce lower output.
> >>
> >> You might find it useful to know how bright you want your light.
> >> For that, you'll need a Lux meter. I have a Lutron LX-102 which
> >> works nicely, and two junk meters I bought on eBay for sanity
> >> checks: <http://www.ebay.com/sch/i.html?_nkw=lux+meter> Get one
> >> that has a wide range. Lowest on mine is 1000 lux, and highest
> >> range is 50,000 lux.
> >>
> >> Find a dark night and an accomplice to operate the meter and send
> >> them down the road to the farthest distance that you might want to
> >> illuminate with your headlight. Use a headlight or flashlight to
> >> light up that area. Have your accompli's take a reading. It will
> >> probably be zero. Now, cut the distance in half and take a
> >> measurement. It will be 2x as bright (lux) at half the distance or
> >> 4x as bright at 1/4th the distance. Adjust the brightness for what
> >> it would have been if the light meter was sufficiently sensitive.
> >>
> >> Converting the brightness (lux) to luminous flux (lumens) requires
> >> that you know the distance to the accomplice, and the illumination
> >> angle. (1 lux = 1 lumen/square-meter)
> >>
> >> The form below makes a mess of bad assumptions but is good enough
> >> for a rough approximation:
> >> <https://www.ledrise.com/shop_content.php?coID=19> Once you know
> >> how many lumens you think you need, and have adjusted for overly
> >> ambitious expectations, you can determine which lighting technology
> >> is suitable.
> >>
> >> Lets say you want to see 8 meters ahead and 20 degrees to each
> >> side (or 40 degree conical beamwidth) at 20 lux, which is rather
> >> dim. Plugging into the web page above, I get 485 lumens needed.
> >> You won't be able to do that with a 3w dynamo, but might squeeze by
> >> with a 6w and an oval shaped beam.
> >>
> >>
> >> -- Jeff Liebermann je...@cruzio.com 150 Felker St #D
> >> http://www.LearnByDestroying.com Santa Cruz CA 95060
> >> http://802.11junk.com Skype: JeffLiebermann AE6KS
> >> 831-336-2558

> >
> > As a very occasional night rider I am interested in battery powered
> > lights but I think that I was attempting to give a thought to a
> > commuter that would use his light a great deal.
> >
>

> I use my lights a great deal because they are on during the day as well
> except on segregated bike paths.
>
> Recharging is 2nd nature to me. Bike gets parked back in the garage,
> li'l round connector gets plugged in, done. Sometimes I deliberately do
> not charge past 8V until shortly before a ride. That improves battery
> lifetime.
>
> The real McCoy would be a worryfree system like in a car where it
> recharges while riding. If I ever switch the road bike front wheel to
> one with a hub dynamo I will do that. Right now it only has a bottle
> dynamo, too much drag and it eats the left side wall of "modern" tires.
> Power output of those is well above 3W at higher speeds if you provide
> the proper electronics. I could go into that but it's nerdy tech stuff.
> Essentially you need what is called a SEPIC or at least a buck converter
> plus some sort of maximum power point tracking (MPPT) control for that
> converter. Sounds more complicated than it really is but do not expect
> the bicycle industry to deliver anything even remotely close anytime soon.
>
> Realistically you could eke out 4-6W depending on you speed. That's not
> enough to feed a MagicShine clone which wants 8W on high plus a watt or
> so for the rear lights. And maybe another 1-2W for the MP3 player. Plus
> the smart phone. And the electric razor :-)
>
> In my case this would work nicely because I need the full 10W total only
> on county roads and in city areas where car drivers tend to misbehave.
> Else it drops to a net load of 4-5W or even much lower. So the dynamo
> would recharge the watt-hours you used up on the county road. Once the
> battery gets full it throttles back. Just like in car.

>
>
> > I notice that a large number of the people in our group have flashing
> > red rear lights and it isn't long before these batteries run down
> > enough that the taillight even blinking is almost entirely
> > unnoticeable. So I don't have much respect for battery power for a
> > great deal of use.
> >
>

> Yep, that's a major nuisance. However ... one can power these lights off
> a regular 8.4V Li-Ion battery or even a dynamo (after rectification) by
> providing a 3V regulator. Small enough to fit where the two AAA cells
> used to be.
>
> If battery rear lights at least had a low-battery warning. Technically
> that would be a piece of cake. But no ... nothing :-(
>
If you're riding a lot during the day with a DRL then you really should consider a dyno light. I was riding with my son this morning, and we passed a guy with a DRL, and I thought that it was unnecessarily bright for a DRL -- and goddamn if it wasn't a round-beam Supernova E3. The two of us were DRL-less, although I was personally in need of recharging.

-- Jay Beattie.

[Jeff Liebermann]

On Wed, 8 Mar 2017 09:34:49 -0800, sms <scharf...@geemail.com>
wrote:

Yes, but they only deliver 68.7 lumens/watt instead of the spec sheet
claim of 200 lumens/watt. As I explained in my previous rant,
reflector loss, lens loss, electronics losses, power source ESR loss,
and temperature derrating, are the culprits. In other words, don't
expect to get spec sheet efficiencies from the finished product.

[Jeff Liebermann]

On Wed, 8 Mar 2017 09:45:43 -0800, sms <scharf...@geemail.com>
wrote:

>On 3/6/2017 9:22 AM, Jeff Liebermann wrote:
>
>> Kinda looks like all of them will sorta deliver 2.5 watts before the
>> core saturates (to provide some level of voltage regulation). Further
>> down the page is a "Low Speed Power" graph, which shows that most can
>> produce 2.0-2.5 watts at 10km/hr. One could assume that the dynamo
>> will deliver 4.0 watts, but that would require buying one of the few
>> better (hub) dynamos listed, and riding at 25-30km/hr (15-19mph).
>>
>> If I were designing or sizing a lighting system suitable for my slow
>> style of "cruising", I would use the worst case 10km/hr (6mph) and 2.0
>> watt figures.

>You've touched on one of the reasons why dynamo lights haven't caught on
>in the U.S..

Touched? I was trying to sledge hammer the reason. Basically, one
design is not going to make everyone happy. Some riders can easily
maintain the speeds necessary to utilize the dynamo at well above it's
rated capacity. Others, like me, can barely make it spin.

I'll spare you my rant on the benefits of a hybrid battery + dynamo
system.

>I wish that it were possible for inexpensive, dynamo powered lights to
>provide adequate illumination for commuting, but it isn't. I recognize
>that few people can afford nearly $500 for a hub dynamo wheel and a
>SuperNova E3 Triple 2. For commuting, where there is no problem
>charging batteries every night, a high power LED set-up is more
>economical and provides better illumination. It's hard enough getting
>people to spend even $25 on a bicycle light, getting them fork out $500
>for a dynamo wheel and a decent dynamo light would be damn near impossible.

So how duz it cost to build one dynamo wheel and headlight?
Prices are my guess(tm) based on experience and random googling.

Shimano Nexus series hubs can be found for about $70.
Wheelsmith spokes are about $0.50/ea or 26 for $18.
Generic rim for $35.
Tire, tube, and rim tape for $20.
B&M Lumotec LUXOS B for $64.
Wiring for free.
====================================
total = $207

While $207 is not cheap, it's much less than your $500 estimate.

[Jeff Liebermann]

On Wed, 8 Mar 2017 09:39:28 -0800, sms <scharf...@geemail.com>
wrote:

>On 3/6/2017 6:27 PM, Jeff Liebermann wrote:

>> <http://www.ebay.com/itm/142066277090>
>> $0.97 gets you a two AAA batteries packaged inside a flasher

>You used to be able to get 2xAA powered flashers, but they weren't 97¢

I haven't seen any with AA batteries in many years. All the cheap
ones seems to AAA.

>The trend now is toward smaller, USB rechargeable tail lights. No reason
>you could not charge these via a dynamo.

Yep. That would make it a hybrid battery + dynamo system, which is
what methinks might be the best compromise. However, it won't work
for megalumen headlights because the dynamo charger will not deliver
enough power to fully recharge the large battery required to run high
power lighting.

Among the cheap tail lights are:
<https://www.amazon.com/Solar-Powered-Bike-Tail-Light/dp/B006FC6CJA>
$2.78.

However, I couldn't find any really cheap Li-Ion rechargeable tail
lights. The best I could do is:
<http://www.ebay.com/itm/USB-Rechargeable-White-Red-Bicycle-Tail-Light-Waterproof-6Modes-COB-led-Tailight-/401141418710>
for $8.50.

[AMuzi]

Low price but no actual German electrons. You call that a
fashion statement?

--
Andrew Muzi
<www.yellowjersey.org/>
Open every day since 1 April, 1971

[sms]

Yes, I was looking at buying everything pre-made from a vendor like
Peter White. A product, not a project.

You can certainly buy a hub, spokes, and rim and assemble it yourself.

You can even buy a good LED lamp for about $20, though without a standlight.

You can buy dynamo wheels on e-Bay (generally NOS) for $100 or so, i.e.
<http://www.ebay.com/itm/282367087029> or
<http://www.ebay.com/itm/282316745203> plus shipping in some cases.

[James]

Thanks. I might look in to it.

Cheers.

--
JS

[Jeff Liebermann]

On Fri, 10 Mar 2017 17:30:57 -0600, AMuzi <a...@yellowjersey.org> wrote:

>> So how duz it cost to build one dynamo wheel and headlight?
>> Prices are my guess(tm) based on experience and random googling.
>>
>> Shimano Nexus series hubs can be found for about $70.
>> Wheelsmith spokes are about $0.50/ea or 26 for $18.

Typo. That should be 36 spokes for $18.

>> Generic rim for $35.
>> Tire, tube, and rim tape for $20.
>> B&M Lumotec LUXOS B for $64.
>> Wiring for free.
>> ====================================
>> total = $207
>>
>> While $207 is not cheap, it's much less than your $500 estimate.

>Low price but no actual German electrons. You call that a
>fashion statement?

Well, Japanese and German electrons should be compatible. However,
the cost of the SON hub needed to produce genuine German electrons is
well over $200. That brings the cost of the wheel to $337. The
prices I picked out of thin air are the cheapest that I could find new
from vendors that sell component parts. I specifically did not use
Banggood and AliExpress to avoid counterfeits and junk. Modifying an
existing front wheel would save $55 for the rim, tire, and tube. Even
running on Japanese electrons, it's still a rather expensive solution
compared to a battery powered headlight and goes a long way to explain
why battery powered lights are more common.

[Joerg]

On 2017-03-10 11:45, jbeattie wrote:

[...]

> If you're riding a lot during the day with a DRL then you really
> should consider a dyno light. I was riding with my son this morning,
> and we passed a guy with a DRL, and I thought that it was
> unnecessarily bright for a DRL -- and goddamn if it wasn't a
> round-beam Supernova E3. The two of us were DRL-less, although I was
> personally in need of recharging.
>

To some extent. I found that when car drivers in an urban area are
particularly inattentive and I switch my front light from 3.5W to 8W
that does get their attention much better. A dynamo can't muster that
much oomph in normal city riding.

On county roads I always ride with full LED power. I found that oncoming
vehicles see me earlier and veer right a bit to give traffic in my
direction more room and thus me a better clearance. Flash mode would be
as bright and save 50% power but that is very annoying to others.

When my front rim is up I will look for a complete wheel or wheel set
with a hub dynamo as long as the cost for the front wheel is under $100.
The value of such a dynamo is limited in this day and age of powerful
Li-Ion batteries. My bigger battery has 60Wh of usable capacity which
means I can ride over 5h with the ship fully lit, music blaring and all
that. A typical dynamo goosed to 5W or so would need at least 20 hours
of solid riding to recharge such a large battery when depleted.
Realistically all a dynamo would do is extend the battery runtime and I
could reduce the size of the battery. That is an advantage but not a big
one because the weight saved by removing two or four 18650 cells is not
that great considering that the hub dynamo adds weight back.

If there'd be a way to goose a dynamo to >10W that would be a different
story. One has to keep in mind that some cyclists want more than just
light. In my case it is just an MP3 player but others have a GPS and a
smart phone. Easily another 3-5W.

With or without dynamo I'll never ride without a battery because then
it's lights out when waiting at an intersection. Very bad at night.

Now, about the bicycle air conditioner ... :-)

--
Regards, Joerg

http://www.analogconsultants.com/

[sms]

On 3/10/2017 3:30 PM, Jeff Liebermann wrote:
> On Wed, 8 Mar 2017 09:39:28 -0800, sms <scharf...@geemail.com>
> wrote:
>
>> On 3/6/2017 6:27 PM, Jeff Liebermann wrote:
>
>>> <http://www.ebay.com/itm/142066277090>
>>> $0.97 gets you a two AAA batteries packaged inside a flasher
>
>> You used to be able to get 2xAA powered flashers, but they weren't 97¢
>
> I haven't seen any with AA batteries in many years. All the cheap
> ones seems to AAA.

But you can still get at least one not-cheap one.

<https://www.amazon.com/dp/B00MQPEW10>
<https://www.aliexpress.com/item/CATEYE-2015-New-Bike-Light-Rear-Tail-Light-Warning-Lamp-Safety-Flashlight-Red-Lights-LD1100-Bicycle/32596712188.html>

[John B.]

On Fri, 10 Mar 2017 15:19:11 -0800, Jeff Liebermann <je...@cruzio.com>
wrote:

The logic of paying $207 dollars for something I never use is
irrefutable :-)
--
Cheers,

John B.

[Sir Ridesalot]

On Friday, March 10, 2017 at 7:52:30 PM UTC-5, Joerg wrote:
Snipped

> With or without dynamo I'll never ride without a battery because then
> it's lights out when waiting at an intersection. Very bad at night.
>
> Now, about the bicycle air conditioner ... :-)
>
> --
> Regards, Joerg
>
> http://www.analogconsultants.com/

Most decent dynamo ights these days have a standlight that'll run for several minutes when the bicycle is stopped.

Cheers

[Sepp Ruf]

Under strict Japanese supervision, even Indonesian electrons work:
https://www.rosebikes.co.uk/article/aid:671388

[Joerg]

I have seen that in Germany. Standlight was very dim though. I prefer it
to be lit normal like it is on my bikes.

[Sir Ridesalot]

You need to look again at more modern stuff because many dynamo hub standlights are quite bright for the time they stay on usually a ferw minutes or so if needed. But then again absolutely NOTHING ever works for you off the shelf.

Cheers

[Joerg]

Wrong, it does and I have written about it here in the NG. I bought a
Cree XM-L based light each for the road bike and the MTB. Of course,
since almost nothing in the world of cycling is very robust or complete
this had to be spiced up. Both lights got diffusor lenses because they
will otherwise blind others and the light distribution wasn't to my
liking. Big deal, you just buy diffusor lenses and install them. Then
the battery holders are lousy. This took a little more work but nothing
that can't be done with a trip to the hardware store and basic hand tools:

http://www.analogconsultants.com/ng/bike/Battbox2.JPG

Why would I want inferior light when I can have a Cree XM-L that affords
me almost the same quality light as a motorcycle has?

This light doesn't just offer a few minutes of "standlight", it offers
north of five hours of light at full blast, whether the bike move or
not. I also have a power outlet on the bike.

[sms]

On 3/10/2017 4:52 PM, Joerg wrote:

> With or without dynamo I'll never ride without a battery because then
> it's lights out when waiting at an intersection. Very bad at night.

I've been doing a lot of design with Li-Ion batteries lately and I
realized that a dynamo is almost a perfect match for two series Li-Ion
batteries when I was helping a colleague charge his Magicshine pack with
a lab supply set to 8.4VDC.

Think of a dynamo putting out 6VAC, with a full wave Schottky rectifier
you'll get about 8V (8.4V - 0.4V of voltage drop. 8V is just about right
to charge two series Li-Ion batteries. Just in case of high speed
riding, stick in an VLDO like a LT3022 with 145mV drop and you're at
7.855V, still enough to get two series Li-Ion cells to full capacity.
The losses are very low, even lower than a switcher.

The reality is that with protected Li-Ion cells you don't even need the
VLDO since the batteries are protected from charging over 4.2V per cell.

At lower output levels, a dynamo could even run a 2 cell battery powered
light if the batteries were removed.

[sms]

On one of my dynamo lights the light automatically dims to extend the
duration of the standlight. On another it does not dim and it stays lit
for only a very short time.

[James]

On 13/03/17 01:57, Joerg wrote:
> On 2017-03-11 16:28, Sir Ridesalot wrote:

>>
>> You need to look again at more modern stuff because many dynamo
>> hub standlights are quite bright for the time they stay on usually
>> a ferw minutes or so if needed. But then again absolutely NOTHING
>> ever works for you off the shelf.
>>
>
> Wrong, it does and I have written about it here in the NG. I bought
> a Cree XM-L based light each for the road bike and the MTB. Of
> course, since almost nothing in the world of cycling is very robust
> or complete this had to be spiced up. Both lights got diffusor lenses
> because they will otherwise blind others and the light distribution
> wasn't to my liking. Big deal, you just buy diffusor lenses and
> install them. Then the battery holders are lousy. This took a little
> more work but nothing that can't be done with a trip to the hardware
> store and basic hand tools:
>
> http://www.analogconsultants.com/ng/bike/Battbox2.JPG
>

You just proved Sir's point. Well done Joerg.

--
JS

[jbeattie]

Hmm, I've managed without a battery box, outlet and motorcycle light on a road bike for like 50 years. I was riding up and down narrow canyons and city streets today without so much as a blinky. The one car that pulled out in even a semi-perilous fashion did so while looking straight at my son and me. No question of our location on the road. I get cars doing the same thing when I'm in a car. They think they can beat you into traffic.

-- Jay Beattie.


-- Jay Beattie.

[Duane]

You gotta love the way he starts out telling Sir that Sir is wrong and then
doing exactly what Sir said that he does. :-)

I seem to get by with off the shelf equipment though I readily admit that I
haven't seen a mountain lion in ages.


--
duane

[Joerg]

On 2017-03-12 13:26, sms wrote:
> On 3/10/2017 4:52 PM, Joerg wrote:
>
>> With or without dynamo I'll never ride without a battery because then
>> it's lights out when waiting at an intersection. Very bad at night.
>
> I've been doing a lot of design with Li-Ion batteries lately and I
> realized that a dynamo is almost a perfect match for two series Li-Ion
> batteries when I was helping a colleague charge his Magicshine pack with
> a lab supply set to 8.4VDC.
>
> Think of a dynamo putting out 6VAC, with a full wave Schottky rectifier
> you'll get about 8V (8.4V - 0.4V of voltage drop. 8V is just about right
> to charge two series Li-Ion batteries. Just in case of high speed
> riding, stick in an VLDO like a LT3022 with 145mV drop and you're at
> 7.855V, still enough to get two series Li-Ion cells to full capacity.
> The losses are very low, even lower than a switcher.
>

If I ever have a hub dynamo I'd use a buck and use a 2nd loop to control
it. The 1st loop would cut the charge if 8.2V has been reached. The 2nd
(inner) loop would set the input voltage to the point where maximum
power is achieved. At the usual brisk ride that most if not all people
in this NG are capable of that voltage level will more likely be well
north of 10V. A dynamo is essentially a current source where you can let
the voltage scoot up until a point is reached where the current drops
off so much that the total power begins to drop. Like MPPT for solar
generation.

> The reality is that with protected Li-Ion cells you don't even need the
> VLDO since the batteries are protected from charging over 4.2V per cell.
>

That's how some cheap Chinese chargers work. Not good as that is no
lomnger single-fault safe. It is as if you'd control a pump via tripping
a GFCI when a certain fill level has been reached.

> At lower output levels, a dynamo could even run a 2 cell battery powered
> light if the batteries were removed.

Then you'd be back to this inferior dynamo lighting which goes out at
the traffic light, or uses dimmed or short-lived light if there is a
supercap installed.

[Joerg]

Yeah, all they've usually got is a supercap of a few Farads. There is
only so much energy to go around, you can either achieve a dim light or
a longer duration but not both.

[Joerg]

Huh? I made it quite clear that my solution works. It does very well.

[sms]

On 3/13/2017 11:06 AM, Joerg wrote:

<snip>

> That's how some cheap Chinese chargers work.

And a lot of non-Chinese chargers as well.

> Not good as that is no
> lomnger single-fault safe. It is as if you'd control a pump via tripping
> a GFCI when a certain fill level has been reached.

Technically there are two safety circuits. First, with an 8.4V output
charger you're limiting the charging voltage to 4.2V per cell. Second,
the protection circuit on each battery, or on the battery pack, limits
the voltage to 4.2V per cell just in case someone plugs in a higher
voltage charger.

I think the simplest dynamo to Li-Ion 2S pack circuit would consist of
only three parts. A 2A Schottky bridge. A filter cap. An 8.2V, 5W zener
diode. I don't think you even need a current limiting resistor because
the dynamo isn't going to put out much more than 500mA.

I don't think you gain much with a buck switcher unless you're often
putting out dynamo voltage well in excess of 6VAC, or unless you want to
do 5.25V for USB charging. You're going to lose some power with the
switcher which is likely to be only 85%-90% efficient.

You could stick in a Murata LXDC55FAAA-203
<http://power.murata.com/data/power/LXDC55FAAA-203_data_sheet_E.pdf>
instead of the zener and do a USB version also with only three parts.
But I know that you love designing your own switchers.

I'm in shock when I see the prices of some of these dynamo to USB
adapters, since the parts cost is only a few bucks.

<http://www.sinewavecycles.com/products/sinewave-revolution>

Here's someone that did it DIY but using a linear regulator.
<http://www.14degrees.org/diy-bicycle-dynamo-usb-charger-for-smartphones-and-battery-packs/>

>
>
>> At lower output levels, a dynamo could even run a 2 cell battery powered
>> light if the batteries were removed.
>
>
> Then you'd be back to this inferior dynamo lighting which goes out at
> the traffic light, or uses dimmed or short-lived light if there is a
> supercap installed.

No, I'm more thinking of a way to have a good light but with dynamo
back-up should the batteries go flat. As well as charging the batteries
during daytime riding when all you're using is the DRL flash mode.

Unfortunately, since dynamo lights are so rare in the U.S. we end up
with sub-standard lighting with poor beam patterns, low intensity, no
flash mode, and inferior brightness when stopped or riding slowly.

I thought it was interesting that Barry Beams mentioned that his light
could work, at less than full intensity, off of dynamo output. He may
have a compelling product for dynamo users that want a brighter, safer,
light but that still want the assurance of not being caught out with
flat batteries. Even Frank realized the need for better lights and
bought an Oculus. And while the Oculus may not be a bargain battery
powered light (even though the price is still pretty reasonable), it's a
lot less than dynamo lights that are not as good.

[Jeff Liebermann]

On Mon, 13 Mar 2017 11:06:18 -0700, Joerg <ne...@analogconsultants.com>
wrote:

>A dynamo is essentially a current source where you can let
>the voltage scoot up until a point is reached where the current drops
>off so much that the total power begins to drop. Like MPPT for solar
>generation.

Not exactly a current source. More like a resistor (coil resistance)
in series with an easily saturated inductor[1]. The problem is that
the bicycle dynamo operates over a range of frequencies, while the
typical solar charge controller operates at a fixed frequency. The
inductive reactance of the dynamo winding appears at variable series
resistance that increases as the dynamo goes faster. There are also
substantial differences in operating frequency between bottle and hub
dynamos:
<http://www.pilom.com/BicycleElectronics/HubDynamo.htm>
"Hubs rotate at a much lower frequency than bottles, and
though they have more poles to somewhat compensate, they still
end up delivering a much lower frequency. At 15 km/h, the
B&M Dymotec6 bottle dynamo (8 poles) outputs 168 Hz AC while
the Shimano DH-3D71 hub dynamo (28 poles) outputs only 28 Hz
at the same speed. At 8 km/h, a 28 pole hub is down to 15 Hz,
which causes visible flicker of the light"

Also, the dynamo iron and number of turns are selected so that the
dynamo saturates at some point near the operating speed and load. The
idea is not so much to regulate the AC output, as it is to reduce
mechanical resistance at higher RPM's.

I tried to build an LTSpice model that simulated a real dynamo and
failed. I couldn't make it act like my bottle dynamo bench tests and
various online graphs. Maybe I'll try again this week. I'm suppose
to be on a (medical) vacation right now.


[1] SON dynamo driving MOSFET bridge:
<https://www.flickr.com/photos/kurtsj00/8480800746/in/photostream>
<http://www.candlepowerforums.com/vb/showthread.php?355392-Spice-code-for-dynamo-output>
The author uses 0.1Hy in series with 2 ohm at 30 Hz. When I swept the
30 Hz over a 10 to 50 Hz range, it didn't look much like a dynamo.