Eyc headlight problem

[Frank Krygowski]

On last night's ride I took the touring bike with its B&M Eyc headlight
powered by an old Union bottle dynamo. (Usually I take a bike with a hub
dyno.) The Lumotec Eyc is about 2/3 down this page:
https://www.peterwhitecycles.com/b&m-hl.php

My friend who rides with me often leaves his headlight off to save his
battery, since we can see so well by mine. But not last night. Right at
the start, my headlight turned itself off. I tried the switch (and I do
dislike "soft" switches buried under rubber covers), I felt the wiring
connections, spun the wheel a few times, then it came back on. Rode ten
feet and it blinked off. Then back on and stayed on, mostly, but would
occasionally blink off then back on.

At one stop to listen to a chorus of frogs, the Eyc was running only its
standlight when it suddenly blinked off. That tells me it's not a wiring
connection or an internal dyno problem. It must be a problem inside the
headlamp itself. Also, it's not triggered by bumps AFAICT, and it
sometimes blinked off while riding a perfectly smooth surface.

Fortunately, it always came back to life and for the rest of the 15 mile
ride it blinked out only occasionally, and for never more than a second.
But its very worrisome.

I'll be writing to Peter White, from whom I bought this. But I'm
wondering if anyone here has had similar troubles with a B&M lamp, or if
anyone wants to get a head start on speculating.

(When my electronic poltergeist starts infecting my bike equipment, it's
a bad, bad sign.)

--
- Frank Krygowski

[Jeff Liebermann]

On Sun, 28 Mar 2021 11:40:08 -0400, Frank Krygowski
<frkr...@sbcglobal.net> wrote:

>I tried the switch (and I do
>dislike "soft" switches buried under rubber covers), I felt the wiring
>connections, spun the wheel a few times, then it came back on. Rode ten
>feet and it blinked off. Then back on and stayed on, mostly, but would
>occasionally blink off then back on.
>
>At one stop to listen to a chorus of frogs, the Eyc was running only its
>standlight when it suddenly blinked off. That tells me it's not a wiring
>connection or an internal dyno problem. It must be a problem inside the
>headlamp itself. Also, it's not triggered by bumps AFAICT, and it
>sometimes blinked off while riding a perfectly smooth surface.
>
>Fortunately, it always came back to life and for the rest of the 15 mile
>ride it blinked out only occasionally, and for never more than a second.
>But its very worrisome.

I've seen similar symptoms with LiIon flashlights and battery powered
bicycle lighting. My guess(tm) is a loose connection somewhere in the
wiring system. As you mention, it could also be inside the light. The
erratic intermittent behavior suggests that it's NOT an electronics
component failure, which would be more cyclic.

Most commonly (in flashlights), I see this caused by the LED COB. The
LED is soldered onto the PCB (printed circuit board) forming the COB
(chip on board). The PCB will flex as the LED heats up eventually
breaking the solder connection. The solder doesn't really melt, but
instead cracks. I fix these using a hot air SMD soldering station:
<https://www.google.com/search?q=hot+air+smd+rework+station&tbm=isch>
Tear the light apart, and touch the LED or slightly bend the PCB while
the lamp is operating. If it flickers, you found the problem. It can
also be components other than the LED, which should be detectable by
bending the PCB or visual inspection. Using the SMD soldering station
takes practice. I suggest you find someone who knows how to use one.

Another problem I've seen are crappy wire connections. These come in
a variety of failures such as cold solder connection, bad crimp,
insulation displacement, jacket creep, and corrosion. The best way to
find these is by probing with a DVM (digital volt meter). The catch
is that you can only find a bad connection if the light is in failure
mode. If it seems to be working normally on the workbench, you're
probably better off taking the light and wiring apart and pulling on
each connection. If the connection moves, stretches, or falls apart,
you found the problem. Corrosion should be obvious. Also, look for
annual rings (usually black) around wires that run through holes in
the PCB. Such rings are cold solder joints, caused by the assembler
being in a hurry, and need to be restarted.

I've only seen one broken wire on a bicycle, which took me weeks to
isolate. I finally found it by pulling on each of the wire ends. One
wire seemed to stretch, indicating a break somewhere. I found where
the insulation necked down from the stretching and spliced the wire.
Problem solved. This wire was NOT under tension and showed no sign of
corrosion, so my guess(tm) is that the wire was defective from the
vendor.

However, my initial wild guess points to the Union bottle dynamo. I
haven't seen any failures with these because I don't use them.
However, if it's as old as you suggest, it might be a good place to
start. Try powering the light with a battery or power supply. Then,
disconnect one of the power wires. The B&M lights usually have a
stand light feature, which is basically a supercap to power the LED
while the generator is NOT turning. If you disconnect the power wire,
and the light goes into stand light mode, and slowly fades away, then
it's working normally. Therefore, the problem is likely NOT in the
dynamo or wiring that power the light. I would need to be after the
stand light circuitry inside the B&M light.

Good luck.

Drivel:
<https://phobia.wikia.org/wiki/Dizoangphobia>
<https://phobia.wikia.org/wiki/Electrophobia>
<https://phobia.wikia.org/wiki/BMWphobia>
<https://phobia.wikia.org/wiki/Cyclophobia>


--
Jeff Liebermann je...@cruzio.com
PO Box 272 http://www.LearnByDestroying.com
Ben Lomond CA 95005-0272
Skype: JeffLiebermann AE6KS 831-336-2558

[Lou Holtman]

Op zondag 28 maart 2021 om 17:40:15 UTC+2 schreef Frank Krygowski:

I have LED spotlights in the bathroom, porch with a promised lifetime of 20000hr or something like that. That is utter BS because they will fail almost all well within that time. It is not the LED that fails but some of the electronic component on the (small) PCB that drives the LED. They fail in a manner you described. I think it is a heat issue.

Lou

[Mark cleary]

All the new fangled bulbs claim to last years and years. I can tell you it is fake news.
Deacon Mark

[sms]

On 3/28/2021 10:01 AM, Jeff Liebermann wrote:

<snip>

> Another problem I've seen are crappy wire connections. These come in
> a variety of failures such as cold solder connection, bad crimp,
> insulation displacement, jacket creep, and corrosion.

I'd first look for bad crimps. I crimp then solder for both a good
electrical and good mechanical connection, except on crimp connections
like Anderson Powerpole where it's not practical to solder after
crimping. If the bottle dynamo uses a bare wire then hopefully there's a
little extra length to create a clean connection.

[Frank Krygowski]

Thanks for the information. I've emailed Peter White and will say what
he says before I dig in further.

But as I said, I suspect the problem is internal to the headlamp because
one of the time it shut down, I was stationary. The light was in
standlight mode, during which it gets no external current supply. The
standlight turned off just as suddenly as the main light was doing.

But again, thanks. (I'm hoping that on the bench, powering this with a
6VDC battery should be as valid as powering it with a dynamo.)

--
- Frank Krygowski

[Jeff Liebermann]

On Sun, 28 Mar 2021 10:50:31 -0700 (PDT), Lou Holtman
<lou.h...@gmail.com> wrote:

>I have LED spotlights in the bathroom, porch with a promised
>lifetime of 20000hr or something like that. That is utter BS
>because they will fail almost all well within that time.

20,000 hrs would be:
20,000hrs / 8766hrs/year = 2.3 years
if you ran it 24x7. Multiply the 2.4 years by whatever fraction of a
day your bathroom and porch lights operate (duty cycle) to obtain the
estimate lifetime.

Note that lifetime for consumer LED bulbs is measured to the point
where the light output (Lumens) decreases to 70% or 80% of initial
value (L70 or L80). Here's some stuff from Australia on the topic:
<http://www.liteonled.com.au/led-light-bulb-life-time/>
Note that nobody is going to run an LED light test for years and
years. So, there are various schemes, such as TM-21, for
extrapolating the lifetime of the LED, again based on loss of output,
not catastrophic failure:
<http://www.liteonled.com.au/buying-guide/led-life-time/l70-lm-80-and-tm-21-data/>

It's this extrapolation, combined with somewhat ignoring catastrophic
failures, and absurd over-control of operating temperature, that is
producing very large numbers for LED lifetime. Also, note that the
only thing that a consumer LED lighting has in common with bicycle
lighting is that both use similar LEDs. The boost or buck inverters
are quite different, the cooling problems are different, and the
operating levels are VERY different. If bicycle lighting was designed
to operate at the temperatures and output levels similar to consumer
LED lighting, we would be blowing up LED bicycle headlights at an
alarming rate. In other words, a 100 watt equivalent LED bulb (14
watts, 1350 lumens) is not the same as a B&M Lumotec Eyc running on
perhaps 3 watts. The major difference is the operating temperature
and the luminaire (housing). The typical consumer lighting fixture is
a bad joke which seems to be designed to incinerate the LED bulb.
Death from overheating is common. On a bicycle, there is moving air
to cool the housing and fewer things in the way before getting to
ambient air. Put a bicycle headlight inside a home luminaire, and
you'll probably be burning out headlights from overheating.

>It
>is not the LED that fails but some of the electronic component on
>the (small) PCB that drives the LED. They fail in a manner you
>described. I think it is a heat issue.

I agree. It's the driver board that dies first, not the LED. However,
that's not the case for all consumer LED lamps. Many of the COB (chip
on board) mounts for LEDs are lacking in heat conduction. How the LED
chip conducts heat to the COB is critical. The construction of the
COB is also critical. For example, it should be ceramic or aluminum,
not G10/FR10 PCB material. Yet, I see flashlights, light bulbs, and
cheap headlights using PCB material.

Another problem is that the consumer LED bulb drivers often use
aluminum electrolytic capacitors. These do not like high temperatures
and conveniently follow a well known temp to lifetime curve:
<https://elc.kemet.com>
<https://www.illinoiscapacitor.com/tech-center/life-calculators.aspx>
Give me the operating electrical conditions and temperatures, and I
can estimate when the capacitor will blow up. Want a 3 year lifetime?
I can provide the capacitor values needed to have most of the
components on the driver PCB blow up simultaneously.

"Selecting the right capacitor to ensure longer life of LEDs"
<https://www.electronicsb2b.com/important-sectors/leds-led-lighting/right-capacitor-to-ensure-longer-life-of-leds/>

"How Electrolytic Capacitors Effect the Reliability of LED Drivers"
<https://www.led-drivers.com.au/blog/how-electrolytic-capacitors-effect-reliability-led-drivers>
On the graph, notice how an operating temperature above 55C case
temperature has a drastic effect on capacitor life.

"Ensure long lifetimes from electrolytic capacitors: A case study in
LED light bulbs"
<https://www.edn.com/ensure-long-lifetimes-from-electrolytic-capacitors-a-case-study-in-led-light-bulbs/>

Note that MLCC (multi-layer ceramic capacitors) are a big improvement
over electrolytic caps, but still have (different) problems. Polymer
caps are a good compromise, but tend to be expensive. I've seen them
in computers and expect to see them in LED lighting eventually.

"Polymer Film Capacitors for LED Drivers"
<https://www.powersystemsdesign.com/articles/polymer-film-capacitors-for-led-drivers/36/5690>

Incidentally, a friend who specializes in lighting electronics design,
once told me that he could recognize the quality and lifetime of a
lighting driver or bulb by just looking at the capacitors. I'm not
sure I could do it today, but thinking back, his method was quite
accurate.

Enough for now.
May the light at the end of the tunnel not be a fire.

[Jeff Liebermann]

Good observation. I also mentioned it at the end of my rant. Whatever
is intermittent is inside the headlight.

>But again, thanks. (I'm hoping that on the bench, powering this with a
>6VDC battery should be as valid as powering it with a dynamo.)

Bottles are usually designed to run 6 volts and 3 watts at about 15
km/hr.
<http://www.myra-simon.com/bike/dynotest.html>
6V should work, but watch out that the light doesn't get too hot.

[John B.]

Some do :-) We bought a new(to us) house about 3 years ago and I
replaced all the interior lighting with the "new" LED (I suppose)
lighting and to date 1 has failed, a circular overhead lamp, which I
replaced about a year ago.
--
Cheers,

John B.

[Frank Krygowski]

The first compact fluorescent light bulb I bought promised something like seven years life.
It lasted only about three years, IIRC. But I had saved the packaging and receipt. I took it back
to Lowe's and they replaced it with out a question, even though they no longer carried the brand.

After that, I began marking the base of each such bulb with the date of its installation. I now
have dozens of CFLs or, more recently, LEDs throughout the house. A very few have failed
early. Almost all have been completely satisfactory.

However, as I've described here in the past, I had an off-brand LED dynamo light fail. The LED
itself went bad. I actually managed (with difficulty) to solder a similar LED in its place, but the
resultant optics were not quite as good. But that headlamp is still in use on our tandem, which
we only rarely ride at night.

That was an Avenir headlight, no longer offered. It was the one that had super-simple electronics,
just a full wave rectifier, a voltage regulator and a few ancillary bits. (It has to be simple if an ME
like me can identify the parts.) An inexpensive B&M Lyt that I opened had a lot more tiny bits.
All of which makes me pessimistic about repairing this B&M Eyc. :-(

- Frank Krygowski

[Sir Ridesalot]

Could it be that a faulty sensor is registering something as getting too hot and shutting down even if for a second or so?

Cheers

[Rolf Mantel]

> Could it be that a faulty sensor is registering something as getting too hot and shutting down even if for a second or so?

More likely a loose element (broken soldering point) on the IC.
At some tail lights, it tended to be the capacitor that broke loose;
I've never heared of it happening to front lights as well.

Rolf

[Sepp Ruf]

Frank Krygowski wrote:

> But again, thanks. (I'm hoping that on the bench, powering this with a
> 6VDC battery should be as valid as powering it with a dynamo.)

Not the AC-Eyc, RTFM.

But how about a new lamp and some real circuit?
<http://tandem-fahren.de/Mitglieder/Framstag/LED/Wollmilchsau/>

[Jeff Liebermann]

On Mon, 29 Mar 2021 12:23:28 +0200, Sepp Ruf <inq...@Safe-mail.net>
wrote:

>Frank Krygowski wrote:
>
>> But again, thanks. (I'm hoping that on the bench, powering this with a
>> 6VDC battery should be as valid as powering it with a dynamo.)
>
>Not the AC-Eyc, RTFM.

That was my suggestion. I assumed that anything with a bridge
rectifier on the AC input would also run on DC.

Nothing in the data sheet:
<https://www.bumm.de/en/products/dynamo-scheinwerfer/produkt/160rtsndi%20.html>

However, the instructions say otherwise:
<https://www.bumm.de/files/Produkte/LUMOTEC%20Eyc_Avy_IQ-XS.PDF>
The headlight can only be powered by a dynamo (AC). Connection
to a DC power source (battery) is not possible.

I don't have a schematic or headlight to dissect. I wonder what
they're doing to prevent DC operation.

There is a 6 to 42VDC Eyc version:
<https://curbsidecycle.com/products/busch-muller-lumotec-eyc-dc-front-light-e-bike>
which probably has a different DC-DC buck converter. I couldn't find
this DC version on the B&M site, but did find this:
<https://www.bumm.de/en/products/e-bike-beleuchtung.html?info=1>
In Germany before 2014, e-bikes had to have a regular
bicycle dynamo powering the light system. Such a dynamo
supplies 6 VC AC. If your e-bike is equipped with a
dynamo, it is not suitable for use with an e-bike headlight.
All our dynamo-powered headlights may be used in this case.

I'm suspicious that this is a safety measure inspired by users
connecting the AC dynamo version of the headlight to an eBike with a
12, 26, or 48 VDC battery and destroying the headlight. Nobody makes
a 6VDC eBike making the risk quite real. However, to be safe and in
case I missed something, I won't suggest that Frank plug his Eyc into
a 6VDC battery.

Peter White Cycles nothing about battery power in the Eyc section at:
<https://www.peterwhitecycles.com/b&m-hl.php>
but does have a note about running the IQ-X on 5VDC from USB power.
We have recently discovered, (April 19, 2017) that the
IQ-X headlight and the Busch & Müller USB-WERK charger
are not compatible. When the cache battery in the
USB-WERK is charging, the IQ-X beam becomes quite dim.
While riding, this can happen for about two seconds,
every thirty seconds or so, and so causes a dangerous
situation, since the rider will briefly not be able to
see the road ahead. If you have the USB-WERK and plan
to use the IQ-X headlight, you should be prepared to
unplug the USB-WERK at night. I recommend using the
Lumotec IQ CYO Premium T Senso Plus or the new IQ-XS
with the USB-WERK, since they are unaffected by this.

My guess(tm) is the IQ-X lights require the peak AC voltage
(6VAC * 1.414 = 8.5V) to operate at full brightness or the charging
current causes a voltage drop to below the IQ-X operating point. The
Eyc might have a similar problem.

>But how about a new lamp and some real circuit?
><http://tandem-fahren.de/Mitglieder/Framstag/LED/Wollmilchsau/>

Google translate did a good job of translating the German into
English. I can't resist looking at the circuit but have only 15
minutes.

Looks like you may have confirmed my low voltage theory:
The Busch + Müller IQ-X E that was evaluated first turned
out to be unusable in the dynamo emergency mode:
up to 20 km / h it remains quite dark and above it
flickers at approx. 1 Hz.
Congrats, you created a relaxation oscillator.

- I don't see an over or under voltage protection (battery management
system) for the LiIon cells on the schematic. However, there's one in
the photo of the red 18650 cells and mentioned in the text. However,
the BMS mentioned in the text is not available in 2S.

- If the red colored 18650 cells in the photo are from "GTL", I have a
few and they are junk. The Samsung cells are much better.

- I don't see the usual resistive divider and timing capacitors on the
555 chip (U2).

- Do you have a LUX meter? If so, I have a lumens measuring
experiment I would like to have you try. Details later.

Thanks, good luck, and I'll be back with more tomorrow.

[Sepp Ruf]

Jeff Liebermann wrote:

> On Mon, 29 Mar 2021 12:23:28 +0200, Sepp Ruf wrote:
>> Frank Krygowski wrote:
>>
>>> But again, thanks. (I'm hoping that on the bench, powering this with a
>>> 6VDC battery should be as valid as powering it with a dynamo.)
>>
>> Not the AC-Eyc, RTFM.
>
> That was my suggestion. I assumed that anything with a bridge
> rectifier on the AC input would also run on DC.

It's tempting, I know.

>> But how about a new lamp and some real circuit?
>> <http://tandem-fahren.de/Mitglieder/Framstag/LED/Wollmilchsau/>
>
> Google translate did a good job of translating the German into
> English. I can't resist looking at the circuit but have only 15
> minutes.
>
> Looks like you may have confirmed my low voltage theory:

Hold on, Jeff, I'm sorry for the little misunderstanding. I only linked to
Ulli Horlacher's latest work there, presented at de.rec.fahrrad on Fri, 26
Mar 2021 08:06:31 +0000 (UTC). Actually, I do not even agree with the
concept of basing one's entire front lighting on one, single beam lamp,
however expensive and reliable it may be.

[sms]

On 3/29/2021 10:41 AM, Jeff Liebermann wrote:

<snip>

> I don't have a schematic or headlight to dissect. I wonder what
> they're doing to prevent DC operation.

I've seen buck/boost converters with an AC input though the AC frequency
from the dynamo would appear to be way too low to be efficient.

Perhaps they say that you can't operate it from DC either because of the
additional losses through the rectifier or because they wanted to ensure
that it isn't hooked up to a 12V or higher electrical system.

What's useful for testing dynamo lights is a 6V filament transformer
i.e. <https://www.aliexpress.com/item/4001271812376.html>, or a Variac.

[sms]

On 3/29/2021 5:02 PM, Sepp Ruf wrote:

<snip>

> Hold on, Jeff, I'm sorry for the little misunderstanding. I only linked to
> Ulli Horlacher's latest work there, presented at de.rec.fahrrad on Fri, 26
> Mar 2021 08:06:31 +0000 (UTC). Actually, I do not even agree with the
> concept of basing one's entire front lighting on one, single beam lamp,
> however expensive and reliable it may be.

Most people in the U.S. with dynamo lights (and there aren't a lot of
them!) also have some sort of battery powered light, even just an
inexpensive USB-rechargeable light.

One reason is to have a backup, but the main reason is that most dynamo
lights don't have a flash DRL mode because that mode isn't legal in some
European countries where most of the dynamo lights are sold. I suspect
that's why Frank bought the Oculus from Barry Beams, even though he'd
never admit it. The only dynamo light I've seen with a flash mode is the
Planet Bike Blaze Dynamo, a pretty low-power light
<https://www.planetbike.com/blaze-dynamo-sl-bike-headlight/>.

I designed a simple circuit to use on dynamo lights, with no DRL but
with a lower-intensity stand-light, to add DRL functionality . It
disconnects and reconnects the AC voltage from the dynamo so the light
goes between full brightness and standlight brightness (this is similar
to the "breathe mode" on some battery powered lights).

[ritzann...@gmail.com]

On Tuesday, March 30, 2021 at 1:59:57 PM UTC-5, sms wrote:
> On 3/29/2021 5:02 PM, Sepp Ruf wrote:
>
> <snip>
> > Hold on, Jeff, I'm sorry for the little misunderstanding. I only linked to
> > Ulli Horlacher's latest work there, presented at de.rec.fahrrad on Fri, 26
> > Mar 2021 08:06:31 +0000 (UTC). Actually, I do not even agree with the
> > concept of basing one's entire front lighting on one, single beam lamp,
> > however expensive and reliable it may be.
> Most people in the U.S. with dynamo lights (and there aren't a lot of
> them!) also have some sort of battery powered light, even just an
> inexpensive USB-rechargeable light.
>

I have a dynamo powered light on one bike. Busch Mueller LED lights. And I have a Princeton Tec AAA battery powered light on my helmet at all times.

[Frank Krygowski]

On 3/30/2021 2:59 PM, sms wrote:
> On 3/29/2021 5:02 PM, Sepp Ruf wrote:
>
> <snip>
>
>> Hold on, Jeff, I'm sorry for the little misunderstanding.  I only
>> linked to
>> Ulli Horlacher's latest work there, presented at de.rec.fahrrad on
>> Fri, 26
>> Mar 2021 08:06:31 +0000 (UTC).  Actually, I do not even agree with the
>> concept of basing one's entire front lighting on one, single beam lamp,
>> however expensive and reliable it may be.
>
> Most people in the U.S. with dynamo lights (and there aren't a lot of
> them!) also have some sort of battery powered light, even just an
> inexpensive USB-rechargeable light.

I very much doubt that statement arose from anywhere but your
imagination. You can't possibly have data to back it up.

It's true there aren't a lot of U.S. cyclists with dyno lights. That's
mainly because there aren't a lot of U.S. cyclists who use their bikes
as anything but toys and exercise machines. There isn't the critical
mass to form a target market for a light that's always available at the
flick of a switch plus gives far better illumination than almost all
battery lights.

> One reason is to have a backup, but the main reason is that most dynamo
> lights don't have a flash DRL mode because that mode isn't legal in some
> European countries where most of the dynamo lights are sold. I suspect > that's why Frank bought the Oculus from Barry Beams, even though he'd
> never admit it.

No, Steve. I bought the Oculus because I was curious especially about
the optical design after it was discussed here pretty extensively; and I
could easily afford it. I'll admit, I did expect to be able to resell it
fairly easily, and that hasn't been true. (I've never bothered to get
into Ebay sales. Perhaps I should.)

> The only dynamo light I've seen with a flash mode is the
> Planet Bike Blaze Dynamo, a pretty low-power light
> <https://www.planetbike.com/blaze-dynamo-sl-bike-headlight/>.

Flashing headlights are just the latest gimmick for the paranoid. They
go with horizontal or vertical flags on the back of the bike, big thick
hats, garish colored clothing, electric horns, turn signals and probably
a dozen other "safety" talismans.

Lots of cultures have good luck talismans.
https://www.invaluable.com/blog/good-luck-charms/
Flashing lights are for bike culture.

--
- Frank Krygowski

[jbeattie]

On Tuesday, March 30, 2021 at 7:29:29 PM UTC-7, Frank Krygowski wrote:
> On 3/30/2021 2:59 PM, sms wrote:
> > On 3/29/2021 5:02 PM, Sepp Ruf wrote:
> >
> > <snip>
> >
> >> Hold on, Jeff, I'm sorry for the little misunderstanding. I only
> >> linked to
> >> Ulli Horlacher's latest work there, presented at de.rec.fahrrad on
> >> Fri, 26
> >> Mar 2021 08:06:31 +0000 (UTC). Actually, I do not even agree with the
> >> concept of basing one's entire front lighting on one, single beam lamp,
> >> however expensive and reliable it may be.
> >
> > Most people in the U.S. with dynamo lights (and there aren't a lot of
> > them!) also have some sort of battery powered light, even just an
> > inexpensive USB-rechargeable light.
> I very much doubt that statement arose from anywhere but your
> imagination. You can't possibly have data to back it up.
>
> It's true there aren't a lot of U.S. cyclists with dyno lights. That's
> mainly because there aren't a lot of U.S. cyclists who use their bikes
> as anything but toys and exercise machines. There isn't the critical
> mass to form a target market for a light that's always available at the
> flick of a switch plus gives far better illumination than almost all
> battery lights.

That's total nonsense. Pre-pandemic, I rode with dozens or hundreds of commuters every day, probably one out of thirty had a dyno -- if even that. People prefer brighter, battery powered lights. Every time I hear your story of cohorts admiring your bright light, I think WTF? I've got SP PD8 dyno hub driving a Luxos B, and its inadequate for night riding anywhere other than lighted streets. Its nice having the dyno when all else fails, but it is not a serious primary light on the roads and in the weather I ride. And yes, I ride with a battery "flasher" -- an L&M that pulses. It differentiates my solid beam from other solid beams, vis., cars and other bikes in two way facilities.

-- Jay Beattie.

[Sir Ridesalot]

I like a flashing mode when starting through an intersection on a main road at night when it's dark. Once through the intersection I'll put the light back on steady mode. I find the flashing (NOT strobing) light gets the attention of most drivers who are facing me. It seems to really cut down on t he number of attempted left-hooks from oncoming drivers. YMMV

I tried a dynamo light at a bike shop one dark night. At slow speeds it was totally inadequate for lighting up the road surface. I bought a good external battery pack battery powered light instead.

Cheers

[James]

Every time I read your story of SP PD8 and Luxos B giving inadequate
light for night riding, I remember how well my SP PV-8 and B&M IQTec
Premium lights the road beautifully in all weather and conditions, and
how I scoffed at the people I rode with at night with their pitiful
battery lights with round beam that didn't light the road well at all.
Even worse were the people with bright lights on their helmet, who
blinded everyone around them and rarely aimed at the road ahead.


--
JS

[jbeattie]

We definitely agree on helmet lights. On a rainy night, riding through the West Hills, the Luxos B is a be-seen light. Maybe your IQTec is more magical.

-- Jay Beattie.

[sms]

On 3/30/2021 9:17 PM, jbeattie wrote:
> On Tuesday, March 30, 2021 at 7:29:29 PM UTC-7, Frank Krygowski wrote:

<snip>

>> It's true there aren't a lot of U.S. cyclists with dyno lights. That's
>> mainly because there aren't a lot of U.S. cyclists who use their bikes
>> as anything but toys and exercise machines. There isn't the critical
>> mass to form a target market for a light that's always available at the
>> flick of a switch plus gives far better illumination than almost all
>> battery lights.
>
> That's total nonsense. Pre-pandemic, I rode with dozens or hundreds of commuters every day, probably one out of thirty had a dyno -- if even that. People prefer brighter, battery powered lights. Every time I hear your story of cohorts admiring your bright light, I think WTF? I've got SP PD8 dyno hub driving a Luxos B, and its inadequate for night riding anywhere other than lighted streets. Its nice having the dyno when all else fails, but it is not a serious primary light on the roads and in the weather I ride. And yes, I ride with a battery "flasher" -- an L&M that pulses. It differentiates my solid beam from other solid beams, vis., cars and other bikes in two way facilities.

Once again, Frank is extrapolating the region where he lives onto the
entire United States.

While the U.S. is unlikely to ever rival the Netherlands in terms of the
percentage of the population that commutes by bicycle, there are regions
of the U.S. where there is a healthy number of commuters, including
Portland and the San Francisco Bay Area; even though the percentage is
pretty low, the absolute number is pretty substantial.

The expense, the relatively low output of dynamo lights, combined with
poorer street lighting of many U.S. cities compared to European cities,
and the lack (other than one) of dynamo headlights with a DRL flash
mode, are reasons why dynamo lights are not popular in the U.S..

In my area a lot of the popular bicycle routes are unlit because they
are multi-use trails along waterways and the County often doesn't allow
lighting because it can disturb wildlife. The speeds on these trails are
often low because of a lot of twists and turns so the output of a dynamo
light, already low, is even less effective.

In Europe, a lot of bicycles come from the factory with dynamo wheels
which greatly reduces the cost to the end-user. After-market accessories
will typically cost six times as much to buy versus the extra cost of
them being standard features from the factory, but for dynamo lighting
it's even worse because a dynamo hub adds only about $10 to the cost of
a bicycle, but buying an after-market dynamo wheel costs upwards of $150.

Frank also needs to understand that when dynamo lights were more popular
in the U.S. (with the bottle generators), this was a time before
rechargeable Li-Ion batteries and before high-output LEDs.

Now personally, I have dynamo wheels on several bicycles in our fleet,
and a dynamo headlights that is usually supplemented with some sort of
battery powered headlight. It's nice to be able to jump on and just ride
without worrying about a battery being charged or how long the battery
will last, and for around town, on well-lit familiar roads, it's
adequate to use only a dynamo light.

BTW, I'm very surprised that you said one out of thirty. Around here
it's probably one out of two hundred.

[Sepp Ruf]

James wrote:
> On 31/3/21 3:17 pm, jbeattie wrote:

>> On March 30, 2021 at 7:29:29 PM UTC-7, Frank Krygowski wrote:
>>> On 3/30/2021 2:59 PM, sms wrote:

>>>> Most people in the U.S. with dynamo lights (and there aren't a
>>>> lot of them!)

So 85% of US bicycle "mechanics" still assume a generator hub is defective
when "notchy"?

>>>> also have some sort of battery powered light, even
>>>> just an inexpensive USB-rechargeable light.
>>>
>>> I very much doubt that statement arose from anywhere but your
>>> imagination. You can't possibly have data to back it up.
>>>
>>> It's true there aren't a lot of U.S. cyclists with dyno lights.
>>> That's mainly because there aren't a lot of U.S. cyclists who use
>>> their bikes as anything but toys and exercise machines. There isn't
>>> the critical mass to form a target market for a light that's always
>>> available at the flick of a switch plus gives far better
>>> illumination than almost all battery lights.

Speaking of market barriers of one or the other sort ... any word from PJW
on how your Eyc lamp matter will proceed?

>> That's total nonsense. Pre-pandemic, I rode with dozens or hundreds
>> of commuters every day, probably one out of thirty had a dyno -- if
>> even that. People prefer brighter, battery powered lights.

Ever spotted one of these, on the road?
<https://www.sinewavecycles.com/collections/lighting/products/sinewave-cycles-beacon>

> Every time I read your story of SP PD8 and Luxos B giving inadequate
> light for night riding, I remember how well my SP PV-8 and B&M IQTec
> Premium lights the road beautifully in all weather and conditions, and
> how I scoffed at the people I rode with at night with their pitiful
> battery lights with round beam that didn't light the road well at all.

Had Jay not shot his night vision by decades of chasing brightly flashing
ambulances, he could scoff at that T-shape artifact in your Cyo-Premium beam!
<http://velo.dyndns.eu/bilder/vergleich2014.jpg>


--
Battery-powered sloths beware!
<https://www.cdc.gov/mmwr/volumes/70/wr/mm7010e4.htm?s_cid=mm7010e4_w#F1_down>

[Frank Krygowski]

On 3/31/2021 12:17 AM, jbeattie wrote:
> On Tuesday, March 30, 2021 at 7:29:29 PM UTC-7, Frank Krygowski wrote:
>> On 3/30/2021 2:59 PM, sms wrote:
>>> On 3/29/2021 5:02 PM, Sepp Ruf wrote:
>>>
>>> <snip>
>>>
>>>> Hold on, Jeff, I'm sorry for the little misunderstanding. I only
>>>> linked to
>>>> Ulli Horlacher's latest work there, presented at de.rec.fahrrad on
>>>> Fri, 26
>>>> Mar 2021 08:06:31 +0000 (UTC). Actually, I do not even agree with the
>>>> concept of basing one's entire front lighting on one, single beam lamp,
>>>> however expensive and reliable it may be.
>>>
>>> Most people in the U.S. with dynamo lights (and there aren't a lot of
>>> them!) also have some sort of battery powered light, even just an
>>> inexpensive USB-rechargeable light.
>> I very much doubt that statement arose from anywhere but your
>> imagination. You can't possibly have data to back it up.
>>
>> It's true there aren't a lot of U.S. cyclists with dyno lights. That's
>> mainly because there aren't a lot of U.S. cyclists who use their bikes
>> as anything but toys and exercise machines. There isn't the critical
>> mass to form a target market for a light that's always available at the
>> flick of a switch plus gives far better illumination than almost all
>> battery lights.
>
> That's total nonsense. Pre-pandemic, I rode with dozens or hundreds of commuters every day, probably one out of thirty had a dyno -- if even that.

You live in the bike commuting capitol of the U.S., but the total number
of your commuters is still minuscule compared to the number of U.S.
bicyclists. A company thinking about "What shall we market?" still looks
on bike commuters, justifiably, as a tiny niche market. As a result,
most cyclists never see a dyno system for sale.

> People prefer brighter, battery powered lights.

People "prefer" what they are told to buy, which is what's on top of the
counter when they wander into a bike shop. If shops had dyno systems
available and explained their advantages, more Portlanders would buy them.

> Every time I hear your story of cohorts admiring your bright light, I think WTF? I've got SP PD8 dyno hub driving a Luxos B, and its inadequate for night riding anywhere other than lighted streets.

I can't explain that (and with you'd trade your system for my Oculus). I
don't know if your problem is electrical (something wrong with the
light), age-related vision problems (but I'm older than you) or just
mis-perception, similar to the one in 50 motorists on yesterday's
freeway drive who chose to blind everyone else by running their high beams.

Again, on the ride where the Eyc gave trouble my friend had his battery
light off most of the way because, as he said, it adds nothing to mine.
Yet its what he uses when he does the ride solo. Now most (not all) of
that ride is on a quiet MUP, but a dark MUP is pretty much the opposite
of your "lighted streets."

Part of your mis-perception might be ever-increasing expectations. In my
view we've had a lot of that in bicycling, where a bike is "too heavy"
if it's 20 pounds, where 9 rear cogs are suddenly way too few, where
actually having to move a mechanical lever makes shifting too difficult,
etc. You seem to have bought into the myth that anything under 250
lumens is too dim.

> Its nice having the dyno when all else fails, but it is not a serious primary light on the roads and in the weather I ride.

I've talked about your wet night riding before, but IIRC you've never
responded to the fact that on a really wet road, a motorist can't even
see his car's headlights on the road. It's an easy to understand optical
phenomenon, and it doesn't mean that you can't see obstacles. Adding
excess lumens to that problem only bounces more down the road into the
eyes of other road users.

> And yes, I ride with a battery "flasher" -- an L&M that pulses. It differentiates my solid beam from other solid beams, vis., cars and other bikes in two way facilities.

Did you really have problems with that before you got a pulsing beam? I
don't ride at night as much as when I was commuting, but I still have
motorists waiting inordinate amounts of time to let me pass. I've never
had a remotely close call.

I wonder if you're experiencing a combination of "safety inflation" plus
placebo effect. As in "All I know is, I've had far fewer flat tires
since I bought my St. Christopher's medal! I'll never ride without it!"


--
- Frank Krygowski

[Frank Krygowski]

On 3/31/2021 12:19 PM, Sepp Ruf wrote:
>
>
> Speaking of market barriers of one or the other sort ... any word from PJW
> on how your Eyc lamp matter will proceed?
>

No word yet. :-(


--
- Frank Krygowski

[sms]

On 3/31/2021 9:19 AM, Sepp Ruf wrote:

<snip>

> Ever spotted one of these, on the road?
> <https://www.sinewavecycles.com/collections/lighting/products/sinewave-cycles-beacon>

That is an ideal solution. Albeit expensive.

A buck regulator with AC input and 5V output could be used to keep a
battery powered lamp charged from a dynamo, and operate the lamp, at
least at lower lumens, solely from the dynamo. Those switching buck
regulator modules cost less than $3.

[Frank Krygowski]

I started using a dyno light in about 1977, an all-in-one Soubitez I
described here, with a vacuum bulb. As I've said, it was inadequate for
dark roads at anything over low speed. But it was fine for being seen on
city streets - and I emphasize, I know that not only by motorist
behavior, but because I had my family drive by to observe and take notes.

My upgrade was the Sanyo roller dyno that James used until recently. Its
"Krypton" headlight bulb seemed better, but its optics were only
slightly better. It was fine for being seen, OK for lighting the road at
moderate speed, but dim at very low speeds - for example, making my way
in a campground's gravel parking lot.

But a halogen headlamp with better optics (a Union) made that set fine
for my uses, which included city and suburb commuting, country roads,
dark MUPs and neighborhood streets. At that stage and earlier I played
around with battery lights others recommended - hopping up small lights
with hotter bulbs, building MR based lights with external rechargeable
batteries, and even trying one of Scharf's LED flashlights. But while
some of those solutions certainly pumped out more lumens, for me they
were not worth the hassle of looking after batteries, remembering to
bring lights along, keeping them secure etc. And honestly, the LED
flashlight was terrible. If focused tightly ts hot spot ruined night
vision, but if focused wider it was too dim.

When I could buy a B&M LED headlight powered by a dyno, all that
experimenting became irrelevant. I considered the problem solved. I
think any B&M dyno light above the (discontinued?) Lyt gives a luxurious
amount of light. I've had no more problems in any riding condition than
I've had with my car's headlights.

I mention this because if Sir Ridesalot tried my 1980 dyno system, he'd
surely say it was inadequate at low speeds for lighting up the road
surface. But the systems I use today are excellent at anything over a
walking pace.

--
- Frank Krygowski

[Roger Merriman]

In many ways there time has gone, in that folks want bright lights, and
though the LED are fine as are the lenses, no getting away from the fact
that batteries can and do push out lot more power, and the gap is only
likely to widen.

>
> Now personally, I have dynamo wheels on several bicycles in our fleet,
> and a dynamo headlights that is usually supplemented with some sort of
> battery powered headlight. It's nice to be able to jump on and just ride
> without worrying about a battery being charged or how long the battery
> will last, and for around town, on well-lit familiar roads, it's
> adequate to use only a dynamo light.

I have one of the exposure lights with a remote switch, has a nice gentle
low, with decent high mode, for the bits that need it, will do 24hrs or
something like that on low, and few hrs on high, but it has runtime plus
lights at rear, so very obvious but since it’s mostly in low, it lasts over
a week in the summer, few days in winter.

Plus easy to swap to the Gravel bike for some night time riding, though
lacks the power for the MTB trails really.

>
> BTW, I'm very surprised that you said one out of thirty. Around here
> it's probably one out of two hundred.
>

I only see Dynamos fitted to cargo bikes, which I see maybe once a week or
so in leafy edge of London.

Roger Merriman

[jbeattie]

Keep praying. I've almost run into cyclists with super-strong headlights because they blend with the super-strong headlights of the cars behind them in two-way facilities next to a road -- which is part of my commute through south waterfront. It is way easier to see cyclists with a low-watt flasher or pulsing light. Bright flashers are a nuisance. I doubt you encounter these facilities or even a fraction of the cyclists encountered on my pre-pandemic commutes. And mix in pedestrians, trains, streetcars and buses (on-coming lights in parallel facilities) and other static light sources from buildings. A solid beam becomes light camouflage.

I also know that my pulsing light makes me more conspicuous at night because I see other cyclists while driving, and a good, pulsing light is noticeable without being annoying. I have no idea what other drivers see, although Joerg is convinced cars stop for him because of his flasher. It may work -- with my L&M Seca 1400, which has a flasher visible from outer-space, I'll run that as punishment for car that appear to be creeping into traffic, but I only do that rarely because it even annoys me.

I night ride on bikes other than my commuter, like my racing bike, and I can just move my battery light around. I'm not going to wire-up four or five bikes. My current night rides are almost entirely on bikes other than my commuter unless I'm going to pick up dinner on the way home, then I lug my dyno equipped commuter up into the hills and use my battery light on full power for the descent, many of which are dangerous even during the day because of the road surface. https://tinyurl.com/3spf5c4p Turn on Westwood and keep going up. Its hard holding on to the bars descending in daylight. https://tinyurl.com/3n3uvf8r

-- Jay Beattie.

[Frank Krygowski]

On 3/31/2021 2:23 PM, jbeattie wrote:
> On Wednesday, March 31, 2021 at 10:01:54 AM UTC-7, Frank Krygowski wrote:
>> On 3/31/2021 12:17 AM, jbeattie wrote:
>>>
>>> And yes, I ride with a battery "flasher" -- an L&M that pulses. It differentiates my solid beam from other solid beams, vis., cars and other bikes in two way facilities.
>> Did you really have problems with that before you got a pulsing beam? I
>> don't ride at night as much as when I was commuting, but I still have
>> motorists waiting inordinate amounts of time to let me pass. I've never
>> had a remotely close call.
>
>> I wonder if you're experiencing a combination of "safety inflation" plus
>> placebo effect. As in "All I know is, I've had far fewer flat tires
>> since I bought my St. Christopher's medal! I'll never ride without it!"
>

> Keep praying. I've almost run into cyclists with super-strong headlights because they blend with the super-strong headlights of the cars behind them in two-way facilities next to a road -- which is part of my commute through south waterfront. It is way easier to see cyclists with a low-watt flasher or pulsing light. ... A solid beam becomes light camouflage.

Ah, yes, Safety Inflation. Corrall the bicyclists into a bi-directional
side track.
http://www.copenhagenize.com/2014/06/explaining-bi-directional-cycle-track.html

Then convince them that they need headlights as bright as cars' to keep
them safe.

Now you can tell them that they also need lower wattage pulsing lights
to distinguish them from the cars. Where does this folly end?

> I also know that my pulsing light makes me more conspicuous at night because I see other cyclists while driving, and a good, pulsing light is noticeable without being annoying. I have no idea what other drivers see, although Joerg is convinced cars stop for him because of his flasher.

Jay, there must be a psychological study on this. You see a cyclist, and
because you are a fan of pulsing lights, you assume you saw him _only_
because of that light. Joerg comes to a stop when a mountain lion
crosses his path and is positive he stopped _only_ because of his
favorite brand of brakes. Someone takes CBD oil and it's the _only_
reason he hasn't died of a heart attack or cancer or both. And of
course, tens of thousands of bicyclists have had their lives saved by
their helmets - when only 850 die, year after year.

Pride of purchase (or pride of advocacy?) imposes a strong desire to
confirm the wisdom of a person's choice. But while your cyclists are
visible only because of a fashionable flavor of headlight, I see night
cyclists who don't have such gimmicks.

> I night ride on bikes other than my commuter, like my racing bike, and I can just move my battery light around. I'm not going to wire-up four or five bikes. My current night rides are almost entirely on bikes other than my commuter unless I'm going to pick up dinner on the way home, then I lug my dyno equipped commuter up into the hills and use my battery light on full power for the descent, many of which are dangerous even during the day because of the road surface. https://tinyurl.com/3spf5c4p Turn on Westwood and keep going up. Its hard holding on to the bars descending in daylight. https://tinyurl.com/3n3uvf8r

I'll admit again that your riding is more extreme than mine. It's also
more extrme than most cyclists. But I have no problems seeing adequately
up to 25 mph with my B&M dyno lights. If I did have a problem, I'd
probably use my (caliper) brakes to slow to a safe speed.

(You _sure_ you don't want to trade for the Oculus? It doesn't have to
be an even trade.)

--
- Frank Krygowski

[sms]

On 3/31/2021 11:23 AM, jbeattie wrote:

<snip>

> Keep praying. I've almost run into cyclists with super-strong headlights because they blend with the super-strong headlights of the cars behind them in two-way facilities next to a road -- which is part of my commute through south waterfront. It is way easier to see cyclists with a low-watt flasher or pulsing light. Bright flashers are a nuisance. I doubt you encounter these facilities or even a fraction of the cyclists encountered on my pre-pandemic commutes. And mix in pedestrians, trains, streetcars and buses (on-coming lights in parallel facilities) and other static light sources from buildings. A solid beam becomes light camouflage.
>
> I also know that my pulsing light makes me more conspicuous at night because I see other cyclists while driving, and a good, pulsing light is noticeable without being annoying. I have no idea what other drivers see, although Joerg is convinced cars stop for him because of his flasher. It may work -- with my L&M Seca 1400, which has a flasher visible from outer-space, I'll run that as punishment for car that appear to be creeping into traffic, but I only do that rarely because it even annoys me.
>
> I night ride on bikes other than my commuter, like my racing bike, and I can just move my battery light around. I'm not going to wire-up four or five bikes. My current night rides are almost entirely on bikes other than my commuter unless I'm going to pick up dinner on the way home, then I lug my dyno equipped commuter up into the hills and use my battery light on full power for the descent, many of which are dangerous even during the day because of the road surface. https://tinyurl.com/3spf5c4p Turn on Westwood and keep going up. Its hard holding on to the bars descending in daylight. https://tinyurl.com/3n3uvf8r

If a bicycle company (I hesitate to call most name-brand bicycle
companies "manufacturers") offered a dynamo wheel option on new bicycles
as say a $50-75 upgrade at the time of purchase then I think they would
be able to sell some decent dynamo lights.

The cost to the bicycle manufacturer of an SP hub dynamo is $10-15 so a
$50 upgrade would be about a break-even price. Brompton offers battery
lighting, dynamo lighting, and no lighting models, though the models
with lighting included aren't sold in the U.S.. For example, the M6L
with no lighting is £1275, with battery lighting is £1350, and with
dynamo lighting it's £1415. So £140 gets you both the dynamo wheel and
the light set. To buy a dynamo wheel for a Brompton costs $195-390, not
including lights. On my DaHon Speed TR, an SP dynamo-equipped wheel was
only $100 (not an upgrade, a whole wheel)
<https://foldingbike.biz/Dahon-Deluxe-Front-Joule-11-Dynohub-wheel-Silver-20>.


A hub dynamo is a lot different accessory than fenders, a luggage rack,
or fenders. Most people aren't going to take their existing wheel and
rebuild it around a hub dynamo that they pay upwards of $100 for.

The fact that so many people now have multiple bicycles is another issue
of course. Spending $150+ for a dynamo and dynamo light on every bicycle
is very costly, while a battery powered light can be easily moved
around, perhaps a few extra mounting brackets are necessary depending on
the light.

At least in my area, another reason to eschew dynamo lights is the
problem of "outrunning" your lights. I'm not talking about a 50MPH
descent I'm talking about having to navigate unlit multi-use paths that
are often the fastest and safest route because of the lack of traffic
lights, stop signs, or intersections. Once I enter the trail system in
Mountain View I can go a very long way, with minimal to no stops. I can
get to Facebook, Google, and Intel, all on MUPs. Even though I could
reach a higher peak speed on regular roads, the average speed is higher
on the the trails.

For a while, Breezer was selling some city bikes with dynamo hub front
wheels but they've stopped doing that because people wanted better
lights than could be powered by a hub dynamo.

I don't know whatever happened to the plans for 12V hub dynamos. There
are 12V bottle dynamos, but for whatever reason 12V hub dynamos never
were marketed
<http://www.velovision.com/ftp-admin/VVArchive/www.velovisionmag.co.uk/showStory37a0.html?storynum=56>.
Maybe they realized that the cyclists that wanted more powerful lights
had already moved on from dynamos and were not coming back, at least
except for one cyclist in Ohio, and the marketing team decided that
developing and manufacturing a product with such a minuscule TAM (total
available market) was not in their best interest.

Sorry to go on and on, but hopefully Frank now understands the issue better.

[Frank Krygowski]

Well, the I already knew the portion that was correct. The portions that
were still incorrect were largely repeats of previous Scharfian posts.
Nothing new there.

Thanks, though, for the pointer to the (prototype?) SON 12V hub. As the
article says, it's already possible to get 6 Watts out of a nominal 3
Watt dynamo, by simply wiring two headlights in series. I did that for a
while, with a switch to run headlight A, or B, or both; and the same
should be possible with a single headlight designed for that duty. But
as with the rest of my experimenting, I stopped that experiment. For me,
a decent dynamo and good LED dyno headlight have solved the lighting
problem.

I do find it satisfying that the person who has argued loudest against
dynamo lights (even constructing a web page to post arguments without
fear of rebuttal) now admits to using them.

--
- Frank Krygowski

[Sepp Ruf]

sms wrote:

> Sorry to go on and on, but hopefully Frank now understands the issue better.

This sort of rhetoric might have been part of why you could not win
reelection in Appleville.

Others have long grasped the issues about 12 volt systems:
In 2001, the 12V hub, literally weighed down by incandescent lamp physics in
legal requirements to provide a rather high voltage already at low speeds,
would have yielded 100 (source) halogen lumens from a geometrically
complicated filament. But 90 lm could already be tweaked by serially
running two 6V bulbs. Today, either a 2001 or a 2021 6V hub can yield more
than 300 lm (net output) from the optically preferential LED, while a cheap
$20 LED dyno lamp such as the Herrmans H-Black MR4 produces 120 lm, and a
beam quality unheard of even in 2011.
<https://fahrradbeleuchtung-info.de/helligkeitsmessung-von-fahrradlampen>

[sms]

On 3/31/2021 5:21 PM, Sepp Ruf wrote:
> sms wrote:
>
>> Sorry to go on and on, but hopefully Frank now understands the issue better.
>
> This sort of rhetoric might have been part of why you could not win
> reelection in Appleville.

Could be, but I think the real reason was that a developer spent about
$100,000 on the campaigns of two opponents. But I will try again next
year, it's no big deal either way, it's essentially a volunteer position.

My big accomplishments, bicycle-related, were pushing through a bicycle
boulevard, protected bicycle lanes, and a new multi-use trail (under
construction). The protected bicycle lanes have been wonderful. It
wasn't that the unprotected bicycle lanes were dangerous, it was that
they were constantly being blocked by errant vehicles and there was no
way that the police could keep up with ticketing or towing. They aren't
heavily used right now because the schools have not brought back
students for in-person classes, but once that happens they will be used
a lot <https://goo.gl/maps/a8X5mehdKCrDi1BQ6>.

> Others have long grasped the issues about 12 volt systems:
> In 2001, the 12V hub, literally weighed down by incandescent lamp physics in
> legal requirements to provide a rather high voltage already at low speeds,
> would have yielded 100 (source) halogen lumens from a geometrically
> complicated filament. But 90 lm could already be tweaked by serially
> running two 6V bulbs. Today, either a 2001 or a 2021 6V hub can yield more
> than 300 lm (net output) from the optically preferential LED, while a cheap
> $20 LED dyno lamp such as the Herrmans H-Black MR4 produces 120 lm, and a
> beam quality unheard of even in 2011.
> <https://fahrradbeleuchtung-info.de/helligkeitsmessung-von-fahrradlampen>

The article about the 12V SON dynamo mentions that you can get 6 watts
out of an existing 3W dynamo at high speeds. So presumably you can get
12 watts out of 6V dynamo at high speeds, but more importantly you can
get 6 watts at lower speeds.

"The obvious significance of this is that bike lights powered by dynamos
could soon become seriously bright - perhaps bright enough to woo back
some of those who have been tempted onto the new generation of
high-power rechargeables."
<http://www.velovision.com/ftp-admin/VVArchive/www.velovisionmag.co.uk/showStory37a0.html?storynum=56>

Of course you also have people like me, and apparently Jay, that
recognize the benefits of dynamo powered lights and the benefits of
battery powered lights, and the situations where each one has the advantage.

Not many people in the U.S. have even heard of Herrmans lights. I have
one of these
<https://herrmans.eu/products/front-lights-4147/dynamo-10038/h-black-pro-dynamo/#technical-data>
on my Dahon folder. Only 200 lumens but a nice beam pattern. It cost €63
from Bike24 in Germany. Also got some of the BBB Fueltank XL bottle
cages from them (now discontinued).

[Ralph Barone]

sms <scharf...@geemail.com> wrote:


<snip>

> I don't know whatever happened to the plans for 12V hub dynamos. There
> are 12V bottle dynamos, but for whatever reason 12V hub dynamos never
> were marketed
> <http://www.velovision.com/ftp-admin/VVArchive/www.velovisionmag.co.uk/showStory37a0.html?storynum=56>.
>

Come on now, Steven, dust off your EE textbooks. A typical hub dynamo
transmits 3 Watts of power over a distance of maybe 3 feet. If you wanted
to double, triple or even transmit 10 times as much power, you don’t need
to change the voltage, just change the internal design of the dynamo. The
obvious solution would be a 3 phase AC generator, with a rectifier/buck
converter inside that puts out a constant 6 V with a much higher current
limit.

Now, inside the dynamo, there may be arguments to be made for a higher
internal voltage before the regulator, but a 6V output should be good up to
the point where nobody would buy one because it would sap too much energy
from the rider.

[Ralph Barone]

It certainly appears that German regulations are impairing progress in
bicycle dynamo lighting. I’d be sorely tempted to abandon all the current
standards and go to a DC 4 wire system (a pair for power and a pair for
comm), with a voltage that accommodates modern Li Ion batteries and modern
electronics. 5 V, 3 A could be a nice place to start. A standard connector,
an existing simple comm protocol and some sort of intelligent power
management scheme could allow dynamo hubs, batteries, lights and
accessories to all plug and play together.

[Jeff Liebermann]

On Wed, 31 Mar 2021 18:27:07 -0700, sms <scharf...@geemail.com>
wrote:

>My big accomplishments, bicycle-related, were pushing through a bicycle
>boulevard, protected bicycle lanes, and a new multi-use trail (under
>construction). The protected bicycle lanes have been wonderful. It
>wasn't that the unprotected bicycle lanes were dangerous, it was that
>they were constantly being blocked by errant vehicles and there was no
>way that the police could keep up with ticketing or towing.

Nicely done. In the People's Republic of Santa Cruz, the "pedestrian"
bridge over the San Lorenzo River is routinely blocked by police,
parks, state, and other vehicle using it as a short-cut when Hwy 1
traffic is at a standstill. The vehicles manage to squeeze over the
bridge with about 1ft clearance on each side. That means that
everyone has to walk or ride ahead or behind the vehicles as they
slowly and carefully crawl across the bridge. I suspect that some
oversized vehicle will eventually try to make it across and create an
Ever Given style blockage. I suggest that you remember this for when
the next bicycle trail is proposed and try to specify some kind of
vehicle barrier or minefield to discourage non-emergency vehicles from
using it as a roadway.

[Jeff Liebermann]

On Thu, 1 Apr 2021 02:01:47 +0000 (UTC), Ralph Barone
<ra...@invalid.com> wrote:

>It certainly appears that German regulations are impairing progress in
>bicycle dynamo lighting. I’d be sorely tempted to abandon all the current
>standards and go to a DC 4 wire system (a pair for power and a pair for
>comm), with a voltage that accommodates modern Li Ion batteries and modern
>electronics. 5 V, 3 A could be a nice place to start. A standard connector,
>an existing simple comm protocol and some sort of intelligent power
>management scheme could allow dynamo hubs, batteries, lights and
>accessories to all plug and play together.

Agreed, mostly. I've been proposing a similar standardized electrical
system for bicycles in this newsgroups for many years. The consensus
seems to be that it's not needed. So, the likely source of a standard
will come from the eBike faction, which does need it, and can make
best use of it.

While I like the simplicity of a 4 wire system, I'm a bit more
ambitious for what can be done with it. In my ideal system, it's a
data bus similar to what is commonly in use in automobiles.
<https://en.wikipedia.org/wiki/Vehicle_bus>
In theory, everything that can be electrically operated can
participate. Headlight, tail light, brakes, performance sensors,
speedometer, odometer, smartphone, GPS, rear view camera, crash
recorder, theft alarm, power management, trainer interface, coffee
warmer, etc. Lots of details would need to hammered out, but I think
the benefits of having a standard interface and power/data bus would
be worth the time and effort.

[James]

Peter White's pictures may be magically illuminating.
https://www.peterwhitecycles.com/headlights.php

Indeed, the Luxos B doesn't appear to be anywhere near as bright as the
B&M IQ Premium.

--
JS

[James]

On 1/4/21 4:01 am, Frank Krygowski wrote:
> On 3/31/2021 12:17 AM, jbeattie wrote:

>
>> People prefer brighter, battery powered lights.
>
> People "prefer" what they are told to buy, which is what's on top of the
> counter when they wander into a bike shop. If shops had dyno systems
> available and explained their advantages, more Portlanders would buy them.

I think they are driven by price more than anything. Battery lights can
be pretty cheap, even if the beam shape is crap and they get attached to
handlebars with rubber bands. No wires. No drag, even if good hub
dynamos have so little drag you don't notice. Easy to remove for a
weekend fast ride or race, etc. They're more convenient - even if they
go flat when you need them most.

--
JS

[Frank Krygowski]

I think a lot of skepticism of dyno systems is due to "safety
inflation." Whatever was good enough last year _must_ be dangerous this
year, because there's something that claims to be "better." It applies
to riding without protective headgear, sliding our feet into toe clips,
removing our hands from the brake levers to shift gears, riding in
daylight with no lights, riding our bikes on roads that don't have walls
between cars and bikes, and much more. It amounts to retroactively
imagining past dangers we were never aware of.

But as with the above examples, "better" is often imaginary or
completely mistaken. In particular, a harsh spot of bright light on a
roadway is NOT better than a well engineered beam that gives even
illumination; and blinding oncoming road users is NOT better than a
properly cut off beam.

A further problem should be an embarrassment to an electrical engineer.
Scharf still fixates on Watts, as if they are the only measurement of
quality. But the lumen per watt output of modern LEDs means 3 Watts
today produces more light than systems he touted ten years ago. Even
more important, advances in optic design mean a nominal 3 Watt headlight
give much better practical illumination of the road than a 10 or 15 Watt
system of the 1990s.

Most people look at a glaring light and think "Oooh, that's bright!
That's what I want!" When its hot spot blinds them so they can't see
with it, they shop for something even more glaring. They don't know that
there's actually something to learn.

--
- Frank Krygowski

[Sepp Ruf]

James wrote:

> Peter White's pictures may be magically illuminating.
> https://www.peterwhitecycles.com/headlights.php
>
> Indeed, the Luxos B doesn't appear to be anywhere near as bright as the
> B&M IQ Premium.

Given the same luminous flux and strictly unintelligent camera, the darker
the photo looks, the better the beam is. Except on busy and wet roads like
Portland. I would never discard a dim or water-ingressed Luxos, it's usable
for mods, even for low & high beam builds legal almost anywhere on this planet.

[jbeattie]

Portland has plenty of shops with dyno hubs. https://www.universalcycles.com/company.php?Company=Shutter%20Precision
https://www.joe-bike.com/product-list/accessories-1109/dynamo-hubs-lights-1263/ https://www.westernbikeworks.com/product/shutter-precision-pd-8x-thru-axle-dynamo-front-hub

Just a smattering. I got my SP PD-8 on sale at Western for $98 or something like that. I got my light at Clever https://www.clevercycles.com/accessories/lights-locks/lights/?brand=866706&min=%240&max=%24350 They also have dyno hubs.

Plenty of supply, just not much demand. Before the plague -- and daylight savings time -- there were reliably one or two other dyno equipped bikes in the racks out of maybe 40 bikes or more.

Most people who commute don't spend that much time riding in the dark and aren't willing to make the effort to get a dyno, although that demographic would be best served since most riding is in facilities and on streets. For a good set-up, its not cheap -- particularly for those who don't build their own wheels. You can get a sale table L&M for $49 and any number of blazing Chi-lights for sub $100.

-- Jay Beattie.

[Rolf Mantel]

Am 01.04.2021 um 18:03 schrieb jbeattie:

> Most people who commute don't spend that much time riding in the dark
> and aren't willing to make the effort to get a dyno, although that
> demographic would be best served since most riding is in facilities
> and on streets.

Yes, you southerners (the 49th latitude is some 50 miles south of here)
don't have winters where the sun goes down before the kids come home
from school.
Round here, in southern Germany, there are three months where you might
be able to chose whether you prefer a dark morning commute or a dark
evening commute (and take 2 weeks of vacation after christmas if you
wish to see the sun at all).

[sms]

A hybrid design would be ideal. Regenerative braking on downhill to
charge the battery but running on the battery alone when going uphill.

With speed sensors, level sensors, and torque sensors, a hybrid bicycle
light might rarely require recharging from the mains, especially because
during daytime riding the battery drain would be limited to the small
amount of power used by a DRL.

[sms]

Including regenerative braking. I think that most people ride a
sufficient distance in the daytime to keep a battery charged.

[sms]

On 3/31/2021 9:39 PM, Jeff Liebermann wrote:
> On Wed, 31 Mar 2021 18:27:07 -0700, sms <scharf...@geemail.com>
> wrote:
>
>> My big accomplishments, bicycle-related, were pushing through a bicycle
>> boulevard, protected bicycle lanes, and a new multi-use trail (under
>> construction). The protected bicycle lanes have been wonderful. It
>> wasn't that the unprotected bicycle lanes were dangerous, it was that
>> they were constantly being blocked by errant vehicles and there was no
>> way that the police could keep up with ticketing or towing.
>
> Nicely done. In the People's Republic of Santa Cruz, the "pedestrian"
> bridge over the San Lorenzo River is routinely blocked by police,
> parks, state, and other vehicle using it as a short-cut when Hwy 1
> traffic is at a standstill. The vehicles manage to squeeze over the
> bridge with about 1ft clearance on each side. That means that
> everyone has to walk or ride ahead or behind the vehicles as they
> slowly and carefully crawl across the bridge. I suspect that some
> oversized vehicle will eventually try to make it across and create an
> Ever Given style blockage. I suggest that you remember this for when
> the next bicycle trail is proposed and try to specify some kind of
> vehicle barrier or minefield to discourage non-emergency vehicles from
> using it as a roadway.

There are a couple of issues with protected bicycle lanes that we've had
to deal with. Some of the streets have houses and the garbage cans need
to be placed in a way that they don't block the bicycle lanes. Street
sweeping is more complicated; eventually there will be specialized
sweepers that can handle this, but for now the protected bicycle lanes
are swept manually into the street then the street sweeper picks up the
debris. Some residents that live on the streets with protected bicycle
lanes were unhappy about losing street parking, but even before the
protected bicycle lanes were put in very few residents parked on the
street. My personal feeling is that public roads should be used for
public access which takes precedence over them being used as parking
areas, but I understand why they were upset since if they have guests
with vehicles those vehicles would have to park on adjoining streets.

[sms]

The mount and the beam shape should definitely be taken into account
when buying battery powered lights.

A good battery powered light doesn't cost $5, but when you get into the
$40-$60 range there are some excellent choices. Personally I'd like to
see aluminum or steel mounting brackets but those aren't that common
(Lezyne had some available but they didn't ship with the light).

As to the beam shape, it's important to remember why dynamo lights have
the beam shape they do. The limited output needs to be precisely
directed on the road. But some spill off to the sides, and upwards, is
actually desirable. Unless you're in Ohio where panel delivery trucks
routinely knock down low-hanging branches, having some amount of light
shining up is extremely useful.

Especially nice are some of the lights where you can use a replaceable
18650, 25650 Li-Ion battery or 3 AA batteries. I have one of these on my
mountain bike and I fabricated an extremely secure metal mount for it
and it sits under the handlebars. The 26650 battery cost more than the
light <https://www.orbtronic.com/26650-battery-protected-li-ion> but I
could have used a much less expensive, lower capacity, 18650 battery (or
three NiMH AA cells or three non-rechargeable AA cells).

[Ralph Barone]

Regenerative braking sounds great, but practically speaking, what
percentage of your life do you actually spend braking on downhill segments?

[AMuzi]

+1
(from 43 something North)

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

[ritzann...@gmail.com]

On Thursday, April 1, 2021 at 10:59:48 AM UTC-5, Frank Krygowski wrote:
> I think a lot of skepticism of dyno systems is due to "safety
> inflation." Whatever was good enough last year _must_ be dangerous this
> year, because there's something that claims to be "better." It applies
> to riding without protective headgear, sliding our feet into toe clips,
> removing our hands from the brake levers to shift gears, riding in
> daylight with no lights, riding our bikes on roads that don't have walls
> between cars and bikes, and much more. It amounts to retroactively
> imagining past dangers we were never aware of.

> --
> - Frank Krygowski

Responding only to the toe clips comments. I vaguely remember riding with toe clips back in the 1980s. It was 30 years ago. I had Alfredo Binda toe straps. I got my first set of Time clipless pedals in the early 1990s. I was delighted to retire the toe clips and never ever use them again. Clipless for me. SPD or SPD-SL on all my bikes.

I've had bikes with stem mounted levers, downtube levers, bar end levers, STI, and Ergo. I'll rate STI and Ergo as a tie. Both are vastly superior to the others. I'm not going back.

[sms]

I never saw the appeal of bar-end levers, but brifters and even separate
bar mount shifters and brake levers make absolute sense.

Toe clips still make sense in situations when you want to ride with
normal shoes but can't get used to not being clipped in.

Hub dynamos still have some appeal to me, though the reality is not many
people are going to incur that kind of expense in order to obtain a
lighting system that is not as good as a battery-powered system that
costs much less. I think that these days people have gotten so used to
the nightly charge routine of phone, car, watch, computer, etc., that
plugging a USB cable into their bicycle light upon arrival at home has
just become habit.

[Frank Krygowski]

Preference is one thing. My point with the list I gave is that all of
those items have been touted, at least by some, as either necessary or
highly desirable for "safety" purposes.

And we live in odd times. Despite this being the safest era that ever
existed, society is ever more fearful of "danger." It leads to all sorts
of weird behavior - prohibiting kids playing away from adult
supervision, requiring protective gear for safe and normal activities,
living in communities with guards at the gate, buying guns for
"protection," etc. It makes people suckers for anything the promises
"safety," including bike equipment that solves safety problems that
never existed.

And simultaneously, we glorify risk taking through TV shows, movies,
video games, YouTube videos and more. Skateboarders, snowboarders,
mountain bikers and BMXers go for "big air." Skydivers, BASE jumpers
drift drivers are heroes.

Some day I'm going to be famous on YouTube for moving my hands away from
my brakes to shift.

--
- Frank Krygowski

[jbeattie]

On Thursday, April 1, 2021 at 3:56:59 PM UTC-7, Frank Krygowski wrote:
> On 4/1/2021 5:41 PM, russell...@yahoo.com wrote:
> > On Thursday, April 1, 2021 at 10:59:48 AM UTC-5, Frank Krygowski wrote:
> >> I think a lot of skepticism of dyno systems is due to "safety
> >> inflation." Whatever was good enough last year _must_ be dangerous this
> >> year, because there's something that claims to be "better." It applies
> >> to riding without protective headgear, sliding our feet into toe clips,
> >> removing our hands from the brake levers to shift gears, riding in
> >> daylight with no lights, riding our bikes on roads that don't have walls
> >> between cars and bikes, and much more. It amounts to retroactively
> >> imagining past dangers we were never aware of.
> >> --
> >> - Frank Krygowski
> >
> > Responding only to the toe clips comments. I vaguely remember riding with toe clips back in the 1980s. It was 30 years ago. I had Alfredo Binda toe straps. I got my first set of Time clipless pedals in the early 1990s. I was delighted to retire the toe clips and never ever use them again. Clipless for me. SPD or SPD-SL on all my bikes.
> >
> > I've had bikes with stem mounted levers, downtube levers, bar end levers, STI, and Ergo. I'll rate STI and Ergo as a tie. Both are vastly superior to the others. I'm not going back.
> Preference is one thing. My point with the list I gave is that all of
> those items have been touted, at least by some, as either necessary or
> highly desirable for "safety" purposes.

Yes, all modern improvements are the result of irrational fear. Take the toilet -- and computers for example.

Nobody in my cohort ever touted STI or step in pedal systems as a safety improvement. And in bike shops, they were sold as conveniences -- or performance enhancers. STI was the secret weapon! Click and sprint!

Dyno hubs and lights are for the Radio Shack set. Dim light but lots of it, like the hand-squeeze flashlights. Most people would rather spend one-fifth as much money and get twice the light at one-quarter the weight for the hour or so it takes them to get home during the winter months. That makes perfect sense. It's not safety inflation. Just look at the Costco flashlight ads: "it lights up a whole room!"

OTOH, super-bright flashers are safety inflation or perhaps irrational fear -- or maybe even rational fear, who knows. I got a bright pulsing rear flasher because I felt imperiled on parts of my commute, and I put reflective tape on my fenders. I do want to be seen at night -- and I have some great reflective booties that are real attention getters. A super-bright front flasher, however, has serious negative impacts when used indiscriminately.

> And we live in odd times. Despite this being the safest era that ever
> existed, society is ever more fearful of "danger." It leads to all sorts
> of weird behavior - prohibiting kids playing away from adult
> supervision, requiring protective gear for safe and normal activities,
> living in communities with guards at the gate, buying guns for
> "protection," etc. It makes people suckers for anything the promises
> "safety," including bike equipment that solves safety problems that
> never existed.

Like? A helmet? I look at my bike and see no safety improvements except for maybe wider tires. My current bikes are really no more or less safe than my bikes 50 years ago. They are more fun to ride, though. Yes, I love STI. I was riding last night, out of the saddle, clicking away merrily as I ascended the endless hills on my pre-dinner loop. F*** DT shifting.

> And simultaneously, we glorify risk taking through TV shows, movies,
> video games, YouTube videos and more. Skateboarders, snowboarders,
> mountain bikers and BMXers go for "big air." Skydivers, BASE jumpers
> drift drivers are heroes.
>
> Some day I'm going to be famous on YouTube for moving my hands away from
> my brakes to shift.

Mmmm. No.

-- Jay Beattie.

[sms]

On 4/1/2021 4:45 PM, jbeattie wrote:

<snip>

> OTOH, super-bright flashers are safety inflation or perhaps irrational fear -- or maybe even rational fear, who knows. I got a bright pulsing rear flasher because I felt imperiled on parts of my commute, and I put reflective tape on my fenders. I do want to be seen at night -- and I have some great reflective booties that are real attention getters. A super-bright front flasher, however, has serious negative impacts when used indiscriminately.

I wish that more lights didn't use the brightest setting for the DRL
flasher, and that instead of a "flash" they used a breathe mode (which
is similar to modulated motorcycle headlights).

I really like this light
<https://www.aliexpress.com/item/32802747811.html> with the "breathe"
mode between 50 lumens and 100 lumens. You get the benefit of a DRL
without annoying oncoming cyclists.

> Like? A helmet? I look at my bike and see no safety improvements except for maybe wider tires. My current bikes are really no more or less safe than my bikes 50 years ago. They are more fun to ride, though. Yes, I love STI. I was riding last night, out of the saddle, clicking away merrily as I ascended the endless hills on my pre-dinner loop. F*** DT shifting.

Braking systems are much better. Retention tabs on forks, shifters where
you don't have to remove your hands from the handlebars, better tires,
better lighting, better helmets.

[Sir Ridesalot]

Back in 2001 I put Campagnolo 9-speed Mirage Ergo levers on my touring bike. I love the fact that I can make a shift whilst struggling up a long or steep hill whilst battling a strong gusty head or side wind. I find that because of the convenience of those Ergo levers that I shift a lot more often which makes a long ride far less fatiguing since I can easily shift into a more efficient gear.

Cheers

[Sir Ridesalot]

I like how in one paragraph is says, "the running time can be 9 hrs with middle luminance" and a bit further down the page it is says, "the running time can be 4 hours and 48 minutes on middle luminance".

Cheers

[AMuzi]

As is often noted, "If not for double standards, we'd have
no standards at all.'

[Frank Krygowski]

On 4/1/2021 7:45 PM, jbeattie wrote:
> On Thursday, April 1, 2021 at 3:56:59 PM UTC-7, Frank Krygowski wrote:
>> On 4/1/2021 5:41 PM, russell...@yahoo.com wrote:
>>> On Thursday, April 1, 2021 at 10:59:48 AM UTC-5, Frank Krygowski wrote:
>>>> I think a lot of skepticism of dyno systems is due to "safety
>>>> inflation." Whatever was good enough last year _must_ be dangerous this
>>>> year, because there's something that claims to be "better." It applies
>>>> to riding without protective headgear, sliding our feet into toe clips,
>>>> removing our hands from the brake levers to shift gears, riding in
>>>> daylight with no lights, riding our bikes on roads that don't have walls
>>>> between cars and bikes, and much more. It amounts to retroactively
>>>> imagining past dangers we were never aware of.
>>>> --
>>>> - Frank Krygowski
>>>
>>> Responding only to the toe clips comments. I vaguely remember riding with toe clips back in the 1980s. It was 30 years ago. I had Alfredo Binda toe straps. I got my first set of Time clipless pedals in the early 1990s. I was delighted to retire the toe clips and never ever use them again. Clipless for me. SPD or SPD-SL on all my bikes.
>>>
>>> I've had bikes with stem mounted levers, downtube levers, bar end levers, STI, and Ergo. I'll rate STI and Ergo as a tie. Both are vastly superior to the others. I'm not going back.
>> Preference is one thing. My point with the list I gave is that all of
>> those items have been touted, at least by some, as either necessary or
>> highly desirable for "safety" purposes.
>
> Yes, all modern improvements are the result of irrational fear. Take the toilet -- and computers for example.
>
> Nobody in my cohort ever touted STI or step in pedal systems as a safety improvement.

Hmm. I thought lawyers were supposed to be good at the fine print. And
heck, my posting was in normal font!

What did I say? I said nothing about your cohort.
I said the items in the list were touted as safety improvements by at
least _some_ as either necessary or desirable for "safety."

Examples: Some of the young racers in that comparative road test (modern
racing bikes vs. older racing bikes) were worried about the safety of
taking their hands off the brakes to shift.

Years ago, we had a poster here who said older pedals were unsafe, that
people should change their pedals. (Sorry, I admit I can't find the post.)

Scharf has gone on and on about the danger of riding in daylight without
a DRL. And companies are definitely pushing ultra-bright taillights for
daytime use. We've had people here describing their purported safety
advantages.

Joerg has gone on and on about the dangers of riding on ordinary roads,
those without separation between motor vehicles and bikes. And living in
Portland, you can't possibly have failed to hear safety claims for
"cycletracks."

And the myth of a bike brain injury epidemic was created to sell
helmets. Bicyclists are only a tiny percentage of serious TBI cases, yet
a huge slice of America thinks nobody should ever pedal without
styrofoam "safety" gear.

> Dyno hubs and lights are for the Radio Shack set.

The "Radio Shack set" may like them. So do many members of the
"practical transportation set." The "long distance travel set." And the
"I don't want to keep fussing with batteries" set. There are others too,
I'm sure.

But you don't have to like them. In fact, you don't have to keep the set
you have. I can trade you for an Oculus that will blind your enemies.
Think how safe you'll feel!

--
- Frank Krygowski

[jbeattie]

Some guy said something about something. My cohort is not lawyers but regular racers who were riding DT shifters when STI was introduced. It was not promoted as a safety device. I remember lining up at a start with my DT shifters next to some early adopter with STI, and his comments was "its my secret weapon" -- and not "I'm so scared; thank God I don't have to take my hands off the bars!"

> Years ago, we had a poster here who said older pedals were unsafe, that
> people should change their pedals. (Sorry, I admit I can't find the post.)

We've had posters here who have said unbelievably stupid things. I switched to clipless because they were more comfortable and stiff with a more positive connection to the pedal. There was no safety claim being made by Look.

>
> Scharf has gone on and on about the danger of riding in daylight without
> a DRL. And companies are definitely pushing ultra-bright taillights for
> daytime use. We've had people here describing their purported safety
> advantages.
>
> Joerg has gone on and on about the dangers of riding on ordinary roads,
> those without separation between motor vehicles and bikes. And living in
> Portland, you can't possibly have failed to hear safety claims for
> "cycletracks."
>
> And the myth of a bike brain injury epidemic was created to sell
> helmets. Bicyclists are only a tiny percentage of serious TBI cases, yet
> a huge slice of America thinks nobody should ever pedal without
> styrofoam "safety" gear.

My helmet has saved me from some stitches. Yes, you've never had an accident of any kind because you are superior. We less superior people may benefit from wearing a helmet, particularly off road -- and particularly in the conditions in which we inferior people ride, e.g. snow, ice, rain and on trail.

> > Dyno hubs and lights are for the Radio Shack set.
> The "Radio Shack set" may like them. So do many members of the
> "practical transportation set." The "long distance travel set." And the
> "I don't want to keep fussing with batteries" set. There are others too,
> I'm sure.

https://bikeportland.org/wp-content/uploads/2018/09/26749140391_bc77316413_h.jpg I would hazard a guess that approximately one of those transportational riders has a dyno lights. I rode across the US from east to west and north to south with a battery light. I did have a roller dynamo while commuting in San Jose in the 70s. And then I got a Belt Beacon and a Wonder Light.

>
> But you don't have to like them. In fact, you don't have to keep the set
> you have. I can trade you for an Oculus that will blind your enemies.
> Think how safe you'll feel!

Hell, I built the wheel and hand drilled and tapped the cast aluminum crown on my CX bike just to mount the mood light. No way I'm getting rid of it. Is it as bright as my L&M urban 800 lumen light that cost one fifth and weighs one quarter of my dyno set up? No. Does my dyno light run forever, yes. That's worth something.

-- Jay Beattie.

[ritzann...@gmail.com]

On Thursday, April 1, 2021 at 6:45:49 PM UTC-5, jbeattie wrote:
> On Thursday, April 1, 2021 at 3:56:59 PM UTC-7, Frank Krygowski wrote:
> > On 4/1/2021 5:41 PM, russell...@yahoo.com wrote:
> > > On Thursday, April 1, 2021 at 10:59:48 AM UTC-5, Frank Krygowski wrote:
> > >> I think a lot of skepticism of dyno systems is due to "safety
> > >> inflation." Whatever was good enough last year _must_ be dangerous this
> > >> year, because there's something that claims to be "better." It applies
> > >> to riding without protective headgear, sliding our feet into toe clips,
> > >> removing our hands from the brake levers to shift gears, riding in
> > >> daylight with no lights, riding our bikes on roads that don't have walls
> > >> between cars and bikes, and much more. It amounts to retroactively
> > >> imagining past dangers we were never aware of.
> > >> --
> > >> - Frank Krygowski
> > >
> > > Responding only to the toe clips comments. I vaguely remember riding with toe clips back in the 1980s. It was 30 years ago. I had Alfredo Binda toe straps. I got my first set of Time clipless pedals in the early 1990s. I was delighted to retire the toe clips and never ever use them again. Clipless for me. SPD or SPD-SL on all my bikes.
> > >
> > > I've had bikes with stem mounted levers, downtube levers, bar end levers, STI, and Ergo. I'll rate STI and Ergo as a tie. Both are vastly superior to the others. I'm not going back.
> > Preference is one thing. My point with the list I gave is that all of
> > those items have been touted, at least by some, as either necessary or
> > highly desirable for "safety" purposes.
> Yes, all modern improvements are the result of irrational fear. Take the toilet -- and computers for example.
>
> Nobody in my cohort ever touted STI or step in pedal systems as a safety improvement. And in bike shops, they were sold as conveniences -- or performance enhancers. STI was the secret weapon! Click and sprint!
>

I have heard the promotion of clipless pedals for safety concerns. Easier to unclip and free your foot if you don't have to reach down and undo the toeclip strap. Of course that really only applies when you are riding cycling shoes with proper clips to lock onto the back of the pedal cage and have the toestraps cinched down tight. Not sure those circumstances happen too often. Now as for me, I have fallen over while clipped into toestraps. And while clipped into clipless pedals too. So not sure much safety of falling over was gained.

As for helmets, I do see the safety aspect of them. I have a big scar on my forehead I've had for almost 40 years due to not having a helmet in an accident. Every single time I look in a mirror I'm reminded of the safety advantage of helmets.

As for dynamo lights. For randonneuring, they are almost required because you are riding so long in darkness at night. Batteries would not work. But for riding around town, I have been more of a battery person than dynamo person. I have both types of lights. Battery lights are much more powerful and provide a couple hours of light. More than enough for evening recreational rides or commuting. One two hour evening rides a couple times a week or commuting morning or evening are the predominant uses of lights. Batteries work very well for these kinds of rides. Its very uncommon for someone to ride all night long and require a dynamo.

I am a proponent of rear red flashing lights. At night. I don't see much benefit during daylight. I always get irritated when I see cyclists in the evening who do not have blinking rear lights. I am such a fan I have two on the back of my saddlebag and one hanging from a ziploc through the back vents of my helmet. More rear blinking lights at night the better.

[Frank Krygowski]

Of course! This is America. Only two or three of those riders have a
light at all.

> I rode across the US from east to west and north to south with a battery light. I did have a roller dynamo while commuting in San Jose in the 70s.

I did east to west with a roller dyno and a halogen headlight. I'm
betting your battery light was nowhere near as effective as my various
B&M lamps, yet we both survived. Yet you seem to now be claiming my
lights are ineffective.

BTW: The worst experience with the light set I had on that trip was
where the C&O Canal Towpath passes through the Paw Paw Tunnel in West
Virginia. The tunnel is long and dark, with a very narrow walkway next
to the remains of the canal. I was forced by the narrowness and bad
surface to ride very slowly, maybe just 2 mph, so slowly that my light
was too dim to show the way very well.

BUT: My modern LED headlights light up as soon as the bike moves. And
most of them have "standlights" that would give enough illumination for
walking even if I somehow had to carry the bike.

>> But you don't have to like them. In fact, you don't have to keep the set
>> you have. I can trade you for an Oculus that will blind your enemies.
>> Think how safe you'll feel!
>
> Hell, I built the wheel and hand drilled and tapped the cast aluminum crown on my CX bike just to mount the mood light. No way I'm getting rid of it. Is it as bright as my L&M urban 800 lumen light that cost one fifth and weighs one quarter of my dyno set up? No. Does my dyno light run forever, yes. That's worth something.

Hmm. It's terribly dim. It's just a "mood light." But you love it.

OK. Enjoy it.

--
- Frank Krygowski

[jbeattie]

I don't love it. I would love a dyno light with a solid 800 lumen output, a little more upward spew and a stand light that was stronger than the light on my give-away key chain from Wells Fargo -- and one with a battery so I could use the light off the bike. We transportational cyclists often need a light for use off the bike. A flasher would be nice for dusk and dawn, but not required. And while we're wishing, how about something lighter and more efficient than a bunch of magnets whirling around. There must be some other way of harvesting electrons.

-- Jay Beattie.

[Mark J.]

While I like my dyno hub and Luxos headlamp for randonneuring, I did two
of my super randonneur series with batteries, and liked 'em just fine.
And the first one was with lead-acid (heavy!) batteries. It was the
superior beam pattern on the Luxos (bought for my commuter) that
persuaded me to convert the rando bike to dyno.

Frankly, prior to well-engineered LED headlights, dynos just didn't
provide enough light for my tastes. Riding all night is much more
stressful when you have to struggle to see road hazards.

Mark J.

[sms]

On 4/1/2021 9:11 PM, jbeattie wrote:

<snip>

> Some guy said something about something.

Similar to one of Fox News's favorite statements when they have no proof
of anything, "some people say..."

<snip>

> My helmet has saved me from some stitches. Yes, you've never had an accident of any kind because you are superior. We less superior people may benefit from wearing a helmet, particularly off road -- and particularly in the conditions in which we inferior people ride, e.g. snow, ice, rain and on trail.

Oy, is Frank still on his anti-fact, anti-helmet jihad? Was he also at
the Capital on January 6th claiming that the election was stolen from Trump?

<snip>

> https://bikeportland.org/wp-content/uploads/2018/09/26749140391_bc77316413_h.jpg I would hazard a guess that approximately one of those transportational riders has a dyno lights. I rode across the US from east to west and north to south with a battery light. I did have a roller dynamo while commuting in San Jose in the 70s. And then I got a Belt Beacon and a Wonder Light.

When I was commuting on Caltrain, and in the bike car, I had the
opportunity to check out a LOT of bicycles ridden by "transportational
cyclists." I usually took my Dahon Speed TR with its Joule (SP) hub
dynamo. It was rare that my bike was not the only one with any dynamo
lighting. Ironically, one other bicycle with a dynamo that I
occasionally saw was owned by an acquaintance who also used Caltrain to
go to SF from the South Bay.

<snip>

> Hell, I built the wheel and hand drilled and tapped the cast aluminum crown on my CX bike just to mount the mood light. No way I'm getting rid of it. Is it as bright as my L&M urban 800 lumen light that cost one fifth and weighs one quarter of my dyno set up? No. Does my dyno light run forever, yes. That's worth something.

Well you point out one more reason why dynamo lights are not popular in
the U.S.. Most riders want a product, not a project. They are unlikely
to buy a hub dynamo and build (or rebuild) a wheel, nor are they likely
to drill and tap holes to mount a light on a bicycle that doesn't have
the appropriate mounting options available.

It's a lot different in countries where many bicycles are sold with a
dynamo hub wheel, either as standard equipment or where there is an
option to substitute a dynamo hub wheel for a non-dynamo wheel at
relatively low cost at time of purchase.

Previously I stated the price differences for a Brompton with no
lighting, battery lighting, or dynamo lighting; the difference at
time-of-purchase is pretty small, but to add a dynamo hub wheel
after-the-fact is expensive.

It's ironic that Frank is arguing with you (and I) about this since the
two of us are probably the few U.S. posters to this group that actually
have bicycles with dynamo lighting (at least as one of our lights).

I guess up in Portland things are better in terms of bike shops, but
down in the Bay Area I've never seen a dynamo light being sold at a bike
shop. Some drug stores and hardware stores used to sell some cheap
bottle dynamo lighting sets. When Payless Drug was going out of business
I picked up a 12V bottle dynamo lighting set that I've had in storage
for about 15 years
<https://drive.google.com/file/d/1ebvxdPmNCfRmFEI9VrnTLsQ15qLrSior>.
Eventually I may at least use the bottle dynamo on my junker bike that I
ride to the store.

[sms]

On 4/2/2021 9:00 AM, jbeattie wrote:

<snip>

> I don't love it. I would love a dyno light with a solid 800 lumen output, a little more upward spew and a stand light that was stronger than the light on my give-away key chain from Wells Fargo -- and one with a battery so I could use the light off the bike. We transportational cyclists often need a light for use off the bike. A flasher would be nice for dusk and dawn, but not required. And while we're wishing, how about something lighter and more efficient than a bunch of magnets whirling around. There must be some other way of harvesting electrons.

Such a light would be wonderful but it would be a stretch with a 6V/3W
dynamo, even at higher speeds where you can get more than 3 watts out of
it. Some LED makers are claiming 300 lumens per watt, at least in the
lab, but 200-250 lumens per watt are what is available commercially at
this time.

A 12V/6W hub dynamo (or even a 9V/4.5W hub dynamo) would make dynamo
lights with sufficient intensity more practical, including a beam
pattern where some upward spew would be possible. DRL flash capability
is trivial to add, as are internal batteries to be able to use it off
the bicycle. But there is just not much of a market for any of this.

[Ralph Barone]

You seem to have it stuck in your head that the internal impedance of a hub
generator is some immutable quantity and not a design parameter. Why not a
6V/12W hub dynamo? Hell, if you were willing to do frequency dependent
series capacitor switching, you can get a lot more than 3W out of a 3W
labelled hub.

[Mark J.]

And yet virtually all the commonly available bike dynamos come out with
a half amp nominal design. (So that wattage is half of voltage). I'm
told their coils "saturate" (or something like that) at a half amp.

I've only been using dynamos over a span of 50 years. I've owned 6V/3W
and 12V/6W generators, and once I saw an 8V/4W claim. If there was a
big improvement to be had with some other amperage design, I would think
someone would have tried to market it by now. Dynamo design might have
some complications, but surely they are well understood at this date.

Mark J.

[Frank Krygowski]

On 4/2/2021 12:00 PM, jbeattie wrote:
> On Friday, April 2, 2021 at 7:41:20 AM UTC-7, Frank Krygowski wrote:
>> On 4/2/2021 12:11 AM, jbeattie wrote:
>>>
>>> I rode across the US from east to west and north to south with a battery light. I did have a roller dynamo while commuting in San Jose in the 70s.
>>
>> I did east to west with a roller dyno and a halogen headlight. I'm
>> betting your battery light was nowhere near as effective as my various
>> B&M lamps, yet we both survived. Yet you seem to now be claiming my
>> lights are ineffective.

>>...

>>
>> My modern LED headlights light up as soon as the bike moves. And
>> most of them have "standlights" that would give enough illumination for
>> walking even if I somehow had to carry the bike.
>>>> But you don't have to like them. In fact, you don't have to keep the set
>>>> you have. I can trade you for an Oculus that will blind your enemies.
>>>> Think how safe you'll feel!
>>>
>>> Hell, I built the wheel and hand drilled and tapped the cast aluminum crown on my CX bike just to mount the mood light. No way I'm getting rid of it. Is it as bright as my L&M urban 800 lumen light that cost one fifth and weighs one quarter of my dyno set up? No. Does my dyno light run forever, yes. That's worth something.
>> Hmm. It's terribly dim. It's just a "mood light." But you love it.
>>
>> OK. Enjoy it.
>

> I don't love it. I would love a dyno light with a solid 800 lumen output...

Seriously now: How did you decide that you need 800 lumens?

I suspect it's because that's what the L&M has to put out to adequately
light the road, plus cook part of it with a hot spot and waste half of
it into the trees. Simplistic beams have inflated the demand for lumens.
Bicycle optics are where automotive optics were in the 1910s.

I'd love to see a test where a sample of road riders tested a lamp whose
optics were properly designed for road use, but whose lumen output
varied. Start low, then keep increasing lumens until they said "This is
enough." I suspect they'd be satisfied with far, far less than 800 lumens.

> a little more upward spew ...

IIRC, you did point out exactly one tree on a low-traffic single lane
road that had twigs that bothered you. Were there others? (Since I ride
almost entirely where motor vehicles pass, I haven't had that problem.)

> and a stand light that was stronger ...

Can you describe the problem you've had because of your unsatisfactory
standlight? (I rode for decades with no standlight at all and no problems.)

> -- and one with a battery so I could use the light off the bike. We transportational cyclists often need a light for use off the bike.

Seriously?

In the two bikes I ride most often at night, I have a giveaway LED light
in the bike bag in case I get a flat away from other lights. But the
batteries die from insufficient shelf life, not from use. What do you
use yours for?

> A flasher would be nice for dusk and dawn, but not required. And while we're wishing, how about something lighter and more efficient than a bunch of magnets whirling around.

Nuclear! At the small cost of some radiation poisoning, we could save as
much as, oh, two ounces!

--
- Frank Krygowski

[Frank Krygowski]

On 4/2/2021 3:32 PM, Mark J. wrote:
> On 4/2/2021 11:59 AM, Ralph Barone wrote:
>>
>> You seem to have it stuck in your head that the internal impedance of
>> a hub
>> generator is some immutable quantity and not a design parameter. Why
>> not a
>> 6V/12W hub dynamo?  Hell, if you were willing to do frequency dependent
>> series capacitor switching, you can get a lot more than 3W out of a 3W
>> labelled hub.
>
> And yet virtually all the commonly available bike dynamos come out with
> a half amp nominal design.  (So that wattage is half of voltage). I'm
> told their coils "saturate" (or something like that) at a half amp.

The inductive reactance of the coils rises with frequency. When properly
designed, this nicely counters the tendency of the generated voltage to
rise with velocity or rpm. If necessary, a pair of zener diodes can trim
the peaks off the sine waves and give a bit closer regulation.

> I've only been using dynamos over a span of 50 years.  I've owned 6V/3W
> and 12V/6W generators, and once I saw an 8V/4W claim.  If there was a
> big improvement to be had with some other amperage design, I would think
> someone would have tried to market it by now.  Dynamo design might have
> some complications, but surely they are well understood at this date.

As I understand it, the present standards arose in countries where they
use bikes more practically, and where they actually, rather than
theoretically, require lights on them at night. The uniform standard
meant one could easily buy replacement bulbs or lamps and be sure they
would be compatible - not unlike the system for sealed beam car headlights.

Mr. Scharf had mocked the 3 Watt power output, but it was proven
adequate for decades even with vacuum bulbs and more primitive optics;
at least, there were no piles of dead night cyclists. Halogen bulbs and
better optics made things much better, and efficient white LEDs and even
better optics have caused an even bigger jump in performance.

But now any small company can slap together an LED, a reflector, a lens,
a clamp and a battery and shoot for ever higher luman numbers. It's hard
to explain to consumers that bigger is not necessarily better, and that
there is such a thing as overkill.

I need to interrupt to make a point: I'd never say that everyone should
be using the systems I'm using. Not everyone wants or needs a light
that's ready all the time, and not everyone is capable of installing a
dynamo and a headlamp.

I will complain, though, about people who cheerfully use primitive high
power lights to blind others. And when people tell me my lights cannot
possibly be adequate, I will rebut.
--
- Frank Krygowski

[sms]

On 4/2/2021 11:59 AM, Ralph Barone wrote:

Not stuck at all. The problem with that approach, and it's already been
done via lowering the impedance by putting two bulbs (or LEDs) in series
is that you don't reach sufficient power at lower speeds.

One thing that some people have done (though it may be illegal in some
countries) is to use a dyno hub designed for a larger wheel on a smaller
wheel. A 20" wheel is around 1010 revolutions per mile, a 28" wheel is
about 720 revolutions per mile. This would get you more output at lower
speeds, but the current would still be 500mA, just at a higher voltage.
And of course it assumes that you want to ride a bicycle with small
wheels! And of course the drag would be greater than a dyno properly
sized to the wheel.

Practically speaking, the advantage of higher output dynamo would be
used with a bridge rectifier and a DC-DC buck converter to charge a
high-power battery powered headlight, or to operate it continuously at
lower than maximum power.

[sms]

On 4/2/2021 12:32 PM, Mark J. wrote:

<snip>

> I've only been using dynamos over a span of 50 years.  I've owned 6V/3W
> and 12V/6W generators, and once I saw an 8V/4W claim.  If there was a
> big improvement to be had with some other amperage design, I would think
> someone would have tried to market it by now.  Dynamo design might have
> some complications, but surely they are well understood at this date.

I think that goal was to not increase the size of the coils and you need
thicker wire in the windings in order to get greater current but not to
get greater voltage.

Like you, I've been using dynamos for more than 50 years, bottle
dynamos, the Sanyo bottom bracket dynamo, and most recently hub dynamos.
Pre-LED, and pre-Li-Ion rechargeable batteries, dynamo lighting had more
appeal (to me) than it does now, though I still have several bicycles in
the fleet with dynamo lighting. I have a new-old-stock 12V bottle
dynamo, but IIRC, the drag on those is pretty high. But I have a beater
bicycle that I use to go to the store that I may install it on since for
those short rides the drag is not going to be an issue.

------------------------------------------------------------------------
“When science discovers the center of the universe, a lot of people will
be disappointed to find they are not it.” – Bernard Bailey
------------------------------------------------------------------------

[John B.]

On Fri, 2 Apr 2021 12:32:51 -0700, "Mark J." <MarkU...@comcast.net>
wrote:

It is because cyclists are such puny power supplies. It would be no
problem to design a more powerful generator into the hub of a bicycle
wheel if the power supply were great enough to power it.
--
Cheers,

John B.

[Mark J.]

No doubt this is why the *wattages* of all these generators are pretty
low. We had a 12V6W bottle generator on our tandem for years. It was
not an efficient model, but still. Even with double the cyclist power,
you could really feel the drag with that thing.

That doesn't explain why the *amperage* is consistently 0.5A on
virtually all the bike generators of the last ~30 years. I'm just
saying this consistency probably has a reason behind it.

Mark J.

[jbeattie]

On Friday, April 2, 2021 at 12:46:51 PM UTC-7, Frank Krygowski wrote:
> On 4/2/2021 12:00 PM, jbeattie wrote:
> > On Friday, April 2, 2021 at 7:41:20 AM UTC-7, Frank Krygowski wrote:
> >> On 4/2/2021 12:11 AM, jbeattie wrote:
> >>>
> >>> I rode across the US from east to west and north to south with a battery light. I did have a roller dynamo while commuting in San Jose in the 70s.
> >>
> >> I did east to west with a roller dyno and a halogen headlight. I'm
> >> betting your battery light was nowhere near as effective as my various
> >> B&M lamps, yet we both survived. Yet you seem to now be claiming my
> >> lights are ineffective.
> >>...
> >>
> >> My modern LED headlights light up as soon as the bike moves. And
> >> most of them have "standlights" that would give enough illumination for
> >> walking even if I somehow had to carry the bike.
> >>>> But you don't have to like them. In fact, you don't have to keep the set
> >>>> you have. I can trade you for an Oculus that will blind your enemies.
> >>>> Think how safe you'll feel!
> >>>
> >>> Hell, I built the wheel and hand drilled and tapped the cast aluminum crown on my CX bike just to mount the mood light. No way I'm getting rid of it. Is it as bright as my L&M urban 800 lumen light that cost one fifth and weighs one quarter of my dyno set up? No. Does my dyno light run forever, yes. That's worth something.
> >> Hmm. It's terribly dim. It's just a "mood light." But you love it.
> >>
> >> OK. Enjoy it.
> >
> > I don't love it. I would love a dyno light with a solid 800 lumen output...
>
> Seriously now: How did you decide that you need 800 lumens?

Who knows how many lumens my 800 max output L&M is really outputting, but on full beam, its adequate for most of my needs, which, BTW, are probably not your needs. Riding to the Thai cart last night, my route went through here: https://tinyurl.com/3dpjx7yv Which goes to here: https://tinyurl.com/c3k3vrbh Those are actually nasty little baby-heads. Keep going out and stop and look at the view -- twinkly lights at night: https://tinyurl.com/yb2fvv7b Now make a hard left up the hill -- that's like 20% and without some upward spew, you lose the road ahead of you, particularly when creeping up hill at a few mph -- and its worse in the cemetery where you lose whole intersections. Sorry no pictures because the Google car apparently does not go through the cemetery. Sometimes you need spew to illuminate landmarks.

> I suspect it's because that's what the L&M has to put out to adequately
> light the road, plus cook part of it with a hot spot and waste half of
> it into the trees. Simplistic beams have inflated the demand for lumens.
> Bicycle optics are where automotive optics were in the 1910s.

Its nice not just seeing people's feet riding up the road on my standard commute: https://tinyurl.com/53z5dcs8 The good thing about the modern era is that dogs wear lighted vests. On that road, you can actually hit your head on a tree if you're not paying attention.

>
> I'd love to see a test where a sample of road riders tested a lamp whose
> optics were properly designed for road use, but whose lumen output
> varied. Start low, then keep increasing lumens until they said "This is
> enough." I suspect they'd be satisfied with far, far less than 800 lumens.
>
> > a little more upward spew ...
>
> IIRC, you did point out exactly one tree on a low-traffic single lane
> road that had twigs that bothered you. Were there others? (Since I ride
> almost entirely where motor vehicles pass, I haven't had that problem.)
>
> > and a stand light that was stronger ...
>
> Can you describe the problem you've had because of your unsatisfactory
> standlight? (I rode for decades with no standlight at all and no problems.)
> > -- and one with a battery so I could use the light off the bike. We transportational cyclists often need a light for use off the bike.
> Seriously?

Absolutely. This is near the end of my commute: https://www.arcgis.com/sharing/rest/content/items/9a1c91f626384b14ac9aacab94cb9f88/resources/DSC00972__1554353835813__w1920.jpg The measly stand light on the LUXOS makes the stairs sketch, and I try to ride the first half of the hill, but in my current condition, that is not possible. 64 wide spaced steps -- that picture is about the half-way point.

> In the two bikes I ride most often at night, I have a giveaway LED light
> in the bike bag in case I get a flat away from other lights. But the
> batteries die from insufficient shelf life, not from use. What do you
> use yours for?

Often seeing where I am going, like on the stairs, sometimes flats or fixing the bike. I use them in the garage a lot, but that doesn't count.

> > A flasher would be nice for dusk and dawn, but not required. And while we're wishing, how about something lighter and more efficient than a bunch of magnets whirling around.
> Nuclear! At the small cost of some radiation poisoning, we could save as
> much as, oh, two ounces!
>

My dyno probably adds a pound, but the commuter bike is such a pig, who knows what dyno weight/drag adds to the overall riding experience.

-- Jay Beattie.

[Frank Krygowski]

The efficiency of bike dynos varies pretty greatly. I could check
numbers, but IIRC top quality hub dynos can hit 65% efficiency. Cheap
bottles can be as low as 40%.

I have a couple of those 12V 6W bottle dynos in a drawer. While I've
never formally tested their efficiency (as I have with some others), my
impression is that it's quite low. I tried one on my mountain bike years
ago and took it off pretty quickly. Also, ISTR the voltage was poorly
regulated, another sign of low design quality.

Another barrier to its use was the lack of an appropriate bulb. I
remember looking through (printed!) catalogs of bulbs but finding
nothing really good. Then there were the optics designed by a grade
school kid... which are not a barrier to sales these days, go figure!


--
- Frank Krygowski

[sms]

On 4/2/2021 4:45 PM, Mark J. wrote

<snip>

> No doubt this is why the *wattages* of all these generators are pretty
> low.  We had a 12V6W bottle generator on our tandem for years.  It was
> not an efficient model, but still.  Even with double the cyclist power,
> you could really feel the drag with that thing.

The bottle generator are pretty inefficient, around 30% while the most
efficient hub dynamos are over 70% efficient.

I haven't tried the VELOGICAL rim dynamo which claims 70% efficiency
<http://www.velogical-engineering.com/velogical-rim-dynamo---standard-bicycle-dynamo---smooth-running-lightweight-efficient>

>
> That doesn't explain why the *amperage* is consistently 0.5A on
> virtually all the bike generators of the last ~30 years.  I'm just
> saying this consistency probably has a reason behind it.

Yes, it has to do with the wire gauge that would be necessary for a
higher current alternator. If you want 6 watts then you're better off
doing a 12V 0.5A alternator than a 6V 1A alternator, especially when
you're trying to minimize size and weight.

[Frank Krygowski]

OK, those photos explain a lot.

If you go back through past discussions on this topic (which is
unlikely), you can find many times when I said the systems I use are not
appropriate for riding off-road in woods. So I'm not surprised if you're
dissatisfied with the hub dyno and its headlight.

In fact, given my and others' statements on that point, I'm honestly
surprised you bought the system you did. You're mis-applying it. It
should be good for road riding, but not for stairs and single track.

--
- Frank Krygowski

[John B.]

On Fri, 2 Apr 2021 16:45:38 -0700, "Mark J." <MarkU...@comcast.net>

Well, how much amperage does one need to power a head and tail light?
Or perhaps more accurately how many watts?
--
Cheers,

John B.

[Ralph Barone]

Pretty much all dynamo design dates back to a time when electronics didn’t
exist. Since light bulbs don’t put out much light at low voltage and tend
to die at high voltage (I seem to recall bulb life being inversely
proportional to the fourth power of voltage), it was important to try and
find a way to produce a constant voltage from a variable speed generator.
The solution that was found was to build the generator with a large leakage
inductance. This inductance provides more and more resistance to current
flow as the frequency (ie: speed) goes up. Since the voltage also goes up
with speed, the two effects cancel each other and you get a reasonably
constant output into a constant resistance load. This became its own
standard (with a 6V output because that was the voltage of three lead acid
cells or four carbon cells).

It is the adherence to this 6 V 500 mA standard which is inhibiting
progress. With modern electronics, it is possible to produce a regulated
output voltage from a variable input voltage. If you have this, there is no
longer the requirement to have so much leakage inductance to regulate the
voltage. The output of the generator also doesn’t have to be 6 V AC, and
if we look at modern LED lights and lithium ion batteries, 6V doesn’t make
sense anymore. 5V actually makes more sense in terms of LED voltage drop,
lithium ion battery voltage and USB powered accessories.

What would make sense to me would be a generator based on modern brushless
DC e-bike motor design, with a maximum output somewhere in the 25 W range,
but normally limited to around half of that (because how much drag do you
want from your dyno hub?). Generate at a slightly higher voltage (for more
efficient rectification, but not so high that the wire in the rotor is too
fragile), then regulate it down to 5V DC for distribution. Add a
controller that figures out how much to ask the generator to produce and
intelligently divides up that power between the battery and the connected
loads and you have a nifty scheme. Unfortunately, the market is to small to
repay the poor shmuck who ends up re-engineering the entire ecosystem.
Maybe somebody with deep pockets (Shimano?) can lay out the standard, then
others can join in.

[AMuzi]

Industry standard head lamps are 6v 2.4w, tail 6v 0.5w,
nominally 6v 3w system.

[Jeff Liebermann]

On Sat, 3 Apr 2021 02:14:42 +0000 (UTC), Ralph Barone
<ra...@invalid.com> wrote:

>Since light bulbs don’t put out much light at low voltage and tend
>to die at high voltage (I seem to recall bulb life being inversely
>proportional to the fourth power of voltage), it was important to try and
>find a way to produce a constant voltage from a variable speed generator.

I beg to differ. As I understand it, the bulb life is thermal
problem, not a voltage problem. For example, a halogen light needs to
be run a rather high temperature so that the tungsten particles
evaporated off the filament are re-deposited back onto the filament,
thus giving the halogen bulb a longer life. This doesn't work unless
the filament is really hot. Since the temperature of the filament is
mostly determined by the power (watts) dissipated in the filament,
lamps of equal operating wattage will last about the same number of
hours no matter what the voltage. Or more crudely, a 6v 1A lamp
running at rated voltage, will last approximately the same number of
hours as a 12v 0.5A bulb running at rated voltage, because they both
burn the same number of watts and operate at the same temperature.

Notice I wrote "approximately". The difference is the surface area of
the helical filament. A low voltage filament uses heavier wire than a
high voltage filament. Since brightness and tungsten evaporation
amount are partially determined by the surface area (for the same
wattage), things go non-linear in a hurry. We would probably be using
heavy gauge filament wire for maximum surface area if tungsten wasn't
so expensive.

Where the 4th power rule comes in is where the operating voltage is
lowered in order to reduce the current, which reduces the dissipated
wattage, which dramatically increases the bulb life. It's not by the
4th power but rather by the 3.5th power:
<https://www.edn.com/incandescent-lamps-and-service-life/>
"Candlepower = (Applied voltage / Rated voltage)3.5 × MSCP
or the mean spherical candlepower at the design voltage.
From there, Lumens = Candlepower × 4 pi "

Reality tends to be more complicated. See the section on Pg 7 "Lamp
Life" in:
<https://www.alliedelec.com/m/d/04fe4bc2ac7e247d70e8e7d88fe48b19.pdf>


--
Jeff Liebermann je...@cruzio.com
PO Box 272 http://www.LearnByDestroying.com
Ben Lomond CA 95005-0272
Skype: JeffLiebermann AE6KS 831-336-2558

[Jeff Liebermann]

On Fri, 2 Apr 2021 20:47:00 -0400, Frank Krygowski
<frkr...@sbcglobal.net> wrote:

>The efficiency of bike dynos varies pretty greatly. I could check
>numbers, but IIRC top quality hub dynos can hit 65% efficiency. Cheap
>bottles can be as low as 40%.

<http://www.myra-simon.com/bike/dynotest.html>
See "Normal Speed Efficiency" bar graph. Looks like efficiency varies
from 22% to 61%.

The first thing to do is throw out the "voltage regulator" that
reduces output (and decreases efficiency) at high RPM (high
frequencies). Replace it with an electronic voltage regulator.
Actually, that's not quite correct. LED's are current driven devices,
so replace it with a current regulator and take whatever voltage is
available.

If there was some way to get the dynamo RPM up high enough, an
alternator would be a further efficiency improvement. Extra points
for a fixed RPM mechanism, where the efficiency is optimized for a
narrow range of RPM's.

The average cyclist has to deliver about 200 watts to sustain 15 mph
on a level roadway. A 3 watt lighting system with 50% dynamo
efficiency will require 6 watts from the cyclist. That's only 3% more
power needed to maintain 15 mph with the lights on.

However, if you want 800 lumens output using 125 lumens/watt LED's
(including optical losses), it will take:
800lum / 125lum/watt = 6.4 watts
to power the light. If someone produced an oversized 50% efficient
bottle dynamo that delivered 6.4 watts, it would require 12.8 watts
from the cyclist or
12.8 / 200 = 6.4%
additional cyclist power to run the lamps. Try that on an exercise
machine or with a cycling computer on a bicycle. It's possible to do
it for short intervals, but not continuously.

What's needed is a dramatic increase in efficiency. If the dynamo
were 100% efficient, then an 800 lumen light would require only a
little more power from the cyclist than the original bottle generator.
100% efficiency is impossible, but there's plenty of room for
improvement between 50% and 100% efficiency.

[ritzann...@gmail.com]

On Friday, April 2, 2021 at 9:41:20 AM UTC-5, Frank Krygowski wrote:
> On 4/2/2021 12:11 AM, jbeattie wrote:
> > I rode across the US from east to west and north to south with a battery light. I did have a roller dynamo while commuting in San Jose in the 70s.
> I did east to west with a roller dyno and a halogen headlight. I'm
> betting your battery light was nowhere near as effective as my various
> B&M lamps, yet we both survived. Yet you seem to now be claiming my
> lights are ineffective.

I did not ride across the USA. But I did ride 4000 miles around Europe in the summer of 1992. I did not have a front light on my loaded touring bike. I did have a red blinky on the back. I never had a reason for a front light. I was on vacation. I had no schedule to keep. I only rode after the sun came up and stopped before the sun went down. My trip was about Memorial Day to Labor Day. So 16+ hours of daylight every day. I stayed at hostels, pensiones, inns, etc. They provided some kind of breakfast in the morning. So I always ate it. And they did not get up at 3AM to get it for a crazy cyclist who wanted to start riding 3 hours before the sun came up. I rode 50-80 miles a day. Which was easy to accomplish while the sun was up. No reason for a front light. The few times I got rained on, I did turn on the rear red blinky to help visibility.

[ritzann...@gmail.com]

Yes I can see that. Depending on how you ride randonneur rides. 200k, no light needed, 13.5 hour time limit. 300k, 20 hour limit, only need light 1/2 hour in the morning and 2-3 hours maybe in the evening. 400k, 27 hour limit, 1 hour morning, 2 hours evening, stop for sleep, 2 hours next morning. On low power batteries can give 4-5 hours of light. 600k, 40 hour limit, 1 hour morning, 2 hours evening, stop for sleep, 1 hour morning, ride all day and get in before need lights in evening. You may be cutting it a bit close if you do not finish quick enough on the second day of riding. No margin for error. But doable. And for the 1000k at 75 hours and the 1200k at 90 hours, they will also work with batteries but will require a new battery/recharge for the second half of the rides. Again doable with the correct planning and no unexpected emergencies arise.

But dynamo on brevets eliminate most of the worry from the unexpected emergencies and you don't have to do any planning at all for night riding. I'd definitely recommend a dynamo for randonneur brevet riding. On my PBP I had a support car so I could have maybe planned to meet my support at approved stops at the right times before dark and gotten fresh batteries. That would have taken a whole lot of planning and luck to work. Not something I want to count on during a timed 1200k. And of course with the much better LED lights for dynamos now, you can get good lighting out of a dynamo. If you are willing to pay the upfront cost and your usage, riding patterns warrant a dynamo.

I used the old filament lights on my dynamo in 2007 and the prior year too when I did an extra 1200k to get ready for PBP. Busch Mueller 6V lights. Two of them for my Shimano dynamo. One each side of the front hub. They provided the minimum amount of light. Minimum. You always wanted more light. I have since upgraded to some B&M LED lights. Two. Much, much better. When I rode brevets, I sometimes rode through the night on 400, 600, 600, 1000, 1200 rides. No sleep stops. So I needed longer run times than batteries could provide.

[Frank Krygowski]

That all sounds correct, but largely moot for our purposes. I doubt
anyone is doing original engineering with the intent of using halogen
bulbs in bike headlights.

In fact, this company http://www.reflectalite.com/ sells LED
replacements for many halogen bulbs.

IME the resultant beam focus is not quite as good, but the light output
is better. I gave one to a friend who still uses a low power battery
light and he says he likes it.


--
- Frank Krygowski

[Frank Krygowski]

As an ME, not an EE, your ideas seem technically possible to me, but are
they really practical? ISTM if you view a dyno light system overall as
something that converts rider wattage to road illumination, there's not
much opportunity for big improvements.

Roughly speaking, dyno efficiencies are high enough that you lose maybe
one or two Watts of rider power there. The other inefficiency is
whatever is wasted as heat instead of light in the LED and its
circuitry. I don't know that efficiency as a percent, but it has to be
minor. I know some LEDs are now pushing 200+ lumens per watt. Properly
focused, that should allow 35 mph descents, and almost nobody wants to
go that fast on a bike at night. Headlights using those LEDs should be
enough to satisfy anyone this side of "more lumens are always necessary"
craziness.

I'm aware of the reasons for 5V electronics, but given modern electronic
expertise, I'd think it wouldn't be difficult to inexpensively mass
produce an efficient 6VAC to 5VDC transformer.

Disclaimer: Again, I'm a Mechanical Engineer, not an Electrical Engineer.

--
- Frank Krygowski

[Ralph Barone]

OK. First off, putting two LEDs in series raises the impedance, and it
works by allowing the voltage from the generator to go up. If you had a bit
of intelligent electronics (a frequency sensor with some hysteresis), you
could short out the second LED at low speeds where there isn’t enough
voltage to drive two in series.

> One thing that some people have done (though it may be illegal in some
> countries) is to use a dyno hub designed for a larger wheel on a smaller
> wheel. A 20" wheel is around 1010 revolutions per mile, a 28" wheel is
> about 720 revolutions per mile. This would get you more output at lower
> speeds, but the current would still be 500mA, just at a higher voltage.
> And of course it assumes that you want to ride a bicycle with small
> wheels! And of course the drag would be greater than a dyno properly
> sized to the wheel.
>
> Practically speaking, the advantage of higher output dynamo would be
> used with a bridge rectifier and a DC-DC buck converter to charge a
> high-power battery powered headlight, or to operate it continuously at
> lower than maximum power.

You’re almost there. The other advantage of a DC-DC converter (don’t get
stuck on buck - it could be that a boost or buck-boost or Cuk is the way to
go) is that it acts as a DC transformer allowing the system (through a
change in duty cycle) to change the effective impedance of the LED to a
value that better matches the source impedance of the dynamo hub at that
particular speed, thereby maximizing power output at all speeds.

[Ralph Barone]

Because that’s what Sturmey-Archer did?

[sms]

On 4/2/2021 4:47 PM, jbeattie wrote:

<snip>

> Its nice not just seeing people's feet riding up the road on my standard commute: https://tinyurl.com/53z5dcs8 The good thing about the modern era is that dogs wear lighted vests. On that road, you can actually hit your head on a tree if you're not paying attention.

Jay, how is it possible that a panel truck did not drive by and knock
down any low hanging branches? Why would you need your bicycle headlight
to have any upward spill to illuminate low hanging branches that could
not possibly exist? You need to call your city's public works department
and demand that they send out a tall truck to knock down any low-hanging
branches (for those that are new here, one poster claimed that any
upward spill of lights to illuminate low-hanging branches was
unnecessary because trucks driving by, close to the edge of the road,
would knock down and such branches).

Seriously though, it’s strange to see complaints about bicycle lights
that do more than simply illuminate the patch of road directly in front
of the bicycle. Yes, that’s what dynamo lights were originally designed
to do, but it was because that with 2.4-3 watts of power from the
dynamo, and an incandescent bulb, they could not do much else. You also
have the StVZO standards which most dynamo lights adhere to, which is
kind of a Catch-22 when it comes to the U.S. since those very standards
make most dynamo lights less than optimal. Reality is that it's a _good_
thing to have some upward spill and side spill.

One exception in dynamo lights is the Supernova E3 Triple 2
<https://supernova-lights.com/en/e3-triple-2/>, which give sufficient
upward and side illumination, but it Is NOT StVZO approved, the
Supernova web site states "The E3 Triple light is not available in
Germany, for legal reasons. Customers outside Germany can order it via
phone or e-mail." Peter White sells it for $251. Combine a 70% efficient
SP PD-8 dynamo wheel with the Supernova E3 Triple 2 and you’d have a
good dynamo lighting system for less than $600, depending on the quality
of the rim and spokes you choose. Add in a circuit that simulates a DRL
by enabling switching between standlight and full brightness. Get one
light and one wheel for every bicycle in your fleet.

[Frank Krygowski]

On 4/3/2021 1:45 AM, Jeff Liebermann wrote:
> On Fri, 2 Apr 2021 20:47:00 -0400, Frank Krygowski
> <frkr...@sbcglobal.net> wrote:
>
>> The efficiency of bike dynos varies pretty greatly. I could check
>> numbers, but IIRC top quality hub dynos can hit 65% efficiency. Cheap
>> bottles can be as low as 40%.
>
> <http://www.myra-simon.com/bike/dynotest.html>
> See "Normal Speed Efficiency" bar graph. Looks like efficiency varies
> from 22% to 61%.

OK, my memory was being too optimistic about the low end dynamos.

>
> The first thing to do is throw out the "voltage regulator" that
> reduces output (and decreases efficiency) at high RPM (high
> frequencies). Replace it with an electronic voltage regulator.

It's not clear to me that the built-in voltage regulation represents a
loss in efficiency. That is, I don't think the power is being taken from
the rider's input by the coils and magnets, then converted to heat by
the inductive reactance. My understanding is that what would be
increased power at higher speed is simply never produced.

I know from private correspondence that David Gordon Wilson (of MIT and
_Bicycling Science_) said he was once working on a scheme to produce a
constant rpm bike dynamo, but once he understood how they worked, he
stopped thinking about his scheme.

> If there was some way to get the dynamo RPM up high enough, an
> alternator would be a further efficiency improvement. Extra points
> for a fixed RPM mechanism, where the efficiency is optimized for a
> narrow range of RPM's.

The rotational speed of a bottle dynamo is pretty high! Over 4000 rpm at
12 mph.

> The average cyclist has to deliver about 200 watts to sustain 15 mph
> on a level roadway. A 3 watt lighting system with 50% dynamo
> efficiency will require 6 watts from the cyclist. That's only 3% more
> power needed to maintain 15 mph with the lights on.
>
> However, if you want 800 lumens output using 125 lumens/watt LED's
> (including optical losses), it will take:
> 800lum / 125lum/watt = 6.4 watts
> to power the light. If someone produced an oversized 50% efficient
> bottle dynamo that delivered 6.4 watts, it would require 12.8 watts
> from the cyclist or
> 12.8 / 200 = 6.4%
> additional cyclist power to run the lamps. Try that on an exercise
> machine or with a cycling computer on a bicycle. It's possible to do
> it for short intervals, but not continuously.
>
> What's needed is a dramatic increase in efficiency. If the dynamo
> were 100% efficient, then an 800 lumen light would require only a
> little more power from the cyclist than the original bottle generator.
> 100% efficiency is impossible, but there's plenty of room for
> improvement between 50% and 100% efficiency.

I strongly, strongly dispute the need for 800 lumens for riding on the
road at night. To me that's very similar to saying bicycles should all
have motorcycle-duty drive chains and spokes.

--
- Frank Krygowski

[sms]

On 4/2/2021 10:45 PM, Jeff Liebermann wrote:

<snip>

> If there was some way to get the dynamo RPM up high enough, an
> alternator would be a further efficiency improvement. Extra points
> for a fixed RPM mechanism, where the efficiency is optimized for a
> narrow range of RPM's.

Just add more poles in the dynamo which would have the equivalent effect.

> The average cyclist has to deliver about 200 watts to sustain 15 mph
> on a level roadway. A 3 watt lighting system with 50% dynamo
> efficiency will require 6 watts from the cyclist. That's only 3% more
> power needed to maintain 15 mph with the lights on.
>
> However, if you want 800 lumens output using 125 lumens/watt LED's
> (including optical losses), it will take:
> 800lum / 125lum/watt = 6.4 watts
> to power the light. If someone produced an oversized 50% efficient
> bottle dynamo that delivered 6.4 watts, it would require 12.8 watts
> from the cyclist or
> 12.8 / 200 = 6.4%
> additional cyclist power to run the lamps. Try that on an exercise
> machine or with a cycling computer on a bicycle. It's possible to do
> it for short intervals, but not continuously.

You have to accept that with the dynamo on you'll be sharing your output
power between forward progress and the light. The bicycle's gearing will
solve this issue, and you'll just be going slower, but you can do it

continuously.

> What's needed is a dramatic increase in efficiency. If the dynamo
> were 100% efficient, then an 800 lumen light would require only a
> little more power from the cyclist than the original bottle generator.
> 100% efficiency is impossible, but there's plenty of room for
> improvement between 50% and 100% efficiency.

There are already SP dynamos with 70%+, so the drag is not as big of an
issue as you make it out to be. 3 watts is enough for a 500 lumen light
(real lumens!) and is certainly sufficient for most road riding. Thermal
issues prevent a single LED from reaching the lumens/watt level
necessary for 500 lumens, but lights like the Supernova E3 triple reach
500 lumens with three LEDs, and have a good beam pattern (not StVZO
compliant).

A hybrid system with the ability to provide higher-output for short
periods of time would be nice. The added weight of a hybrid lighting
system would likely be well worth it as well. Charge the battery in the
daytime, at perhaps 250mA while pedaling on level ground, 500mA when
coasting or on long downhill runs, and 0ma when going uphill. Run the
light solely on dynamo power when full brightness isn't required or when
the battery is exhausted.

But no company is going to make much of an investment in developing such
a system and then tooling up and manufacturing it. The market just isn't
there unless they could get such a system installed at the factory, and
no high-volume bicycle manufacturer wants to that kind of expense.

[Frank Krygowski]

I'm sure the pickup drivers I encounter using their high beams on my
also praise their upward spill and side spill. There are a few of them
that also run LED light bars, or turn them on if someone flashes to
complain about their high beams. It's a MFFY attitude.

But the bit about modern lights "simply illuminate the patch of road
directly in front of the bicycle" is simply false. I've checked several
times and measured nearly a quarter mile to a stop sign illuminated by
my Cyo headlight. The visible beam on the roadway stretches at least 30
feet, and objects on the road are visible farther than that.

As to the panel trucks and overhead branches, I don't know what sort of
bike you ride on what sort of streets if you're got a real danger of
whacking your head on a branch. A bicyclist's head is normally about six
feet off the ground, maximum. That's less than the height of the very
common Ford F-150 pickup. AASHTO's bike facility design manual calls for
a minimum of 8 feet of overhead clearance on a bike path, with 10 feet
desirable.

So somehow motor vehicles are not being damaged by branches six feet
above the road, yet you're at risk of hitting your head? You must be on
an antique high wheeler or some other very unusual bike.
https://en.wikipedia.org/wiki/Tall_bike

Or more likely, are being your usual obtuse self.

--
- Frank Krygowski

[Frank Krygowski]

Long ago, I had three friends who entered a 24 hour event - just "How
far can you ride in 24 hours?" going around and around a few miles of
roadway.

Two of my friends (a fast racer and his sport-tourist father) went out
hot, cranking away at high speed. They burned out in about 8 hours, IIRC
and did not finish.

The third guy who I thought of as very elderly (but not as old as I am
now) just rode and rode at his usual moderate pace. For that particular
event he set a record for his age group, something like 315 miles in 24
hours. They said you always knew it was him approaching in the middle of
the night because you could hear his bottle dyno whirring away.

--
- Frank Krygowski

[Ralph Barone]

I know that you’ll probably disagree about the necessity of doing so, but a
lot of the talk recently in this thread has been about the 3W limit and how
to get around it. My opinion is that once you want to get more power, that
throwing out history and redesigning the generator would be a good idea.

Regarding the 6VAC to 5VDC transformer, yes it’s possible, but certain
things get in the way of doing it efficiently, and changing some of the
system parameters would make it easier to get a DC output without throwing
away too much of your precious power.

[Ralph Barone]

Yes, bulb life is a thermal problem, but filament operating temperature
depends on applied voltage. The filament is heated by V^2/R, and cooled by
conduction back to the base (linear thermal model) and radiation into free
space (fourth power thermal model). Light output is optimized as you get
the tungsten closer to the liquid state, which is also, of course when the
bulb fails. Incandescent lights produce a colour temperature in the 3000 K
range, so I assume the filament is also around that temperature. Tungsten
melts at 3687 K, so you can see that the designers of light bulbs don’t
have much room to play before the filament liquifies.

Obviously, my memory was a bit faulty. As per the Wikipedia article quoted
below, bulb lifetime is not proportional to the inverse fourth power, but
closer to the 14th. So the reality is that if you lower the voltage, you
get MUCH longer life, but no light, and if you raise the voltage, you get a
lot more light, but for a vanishingly short time until the bulb burns out.
It is this trade off which drove the design of dynamo hubs to be the way
they currently are.

LED lamps have different characteristics (light output is pretty much
proportional to current down to the point where there’s not enough voltage
to overcome the voltage drop of the bulb). Modern electronics changes the
game again. Since nobody currently uses incandescent lamps in any new
lights, the “stuckedness” of the dynamo hub industry on 6 VAC, 0.5 A claw
pole generators is a lost opportunity in my mind.

https://en.m.wikipedia.org/wiki/Lamp_rerating

[Ralph Barone]

Jeff Liebermann <je...@cruzio.com> wrote:
> On Fri, 2 Apr 2021 20:47:00 -0400, Frank Krygowski
> <frkr...@sbcglobal.net> wrote:
>
>> The efficiency of bike dynos varies pretty greatly. I could check
>> numbers, but IIRC top quality hub dynos can hit 65% efficiency. Cheap
>> bottles can be as low as 40%.
>
> <http://www.myra-simon.com/bike/dynotest.html>
> See "Normal Speed Efficiency" bar graph. Looks like efficiency varies
> from 22% to 61%.
>
> The first thing to do is throw out the "voltage regulator" that
> reduces output (and decreases efficiency) at high RPM (high
> frequencies). Replace it with an electronic voltage regulator.
> Actually, that's not quite correct. LED's are current driven devices,
> so replace it with a current regulator and take whatever voltage is
> available.
>
> If there was some way to get the dynamo RPM up high enough, an
> alternator would be a further efficiency improvement. Extra points
> for a fixed RPM mechanism, where the efficiency is optimized for a
> narrow range of RPM's.

Don’t tell anybody, but dynamos are alternators. They produce alternating
current.

[Jeff Liebermann]

On Sat, 3 Apr 2021 15:36:31 +0000 (UTC), Ralph Barone
<ra...@invalid.com> wrote:

>Don’t tell anybody, but dynamos are alternators. They produce alternating
>current.

Oops. You're right. I was thinking of getting rid of the magnets and
replacing them with a field winding to provide some better current
regulation. That's one reason why gasoline powered
inverter-generators are more efficient than connecting the load
directly to the generator. I haven't run any numbers, so I'm not sure
if this will work.

Thanks.