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Eyc headlight problem



 
 
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  #111  
Old April 4th 21, 01:13 AM posted to rec.bicycles.tech
JBeattie
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Posts: 5,661
Default Eyc headlight problem

On Saturday, April 3, 2021 at 4:32:13 PM UTC-7, Frank Krygowski wrote:
On 4/3/2021 12:57 PM, Jeff Liebermann wrote:
On Sat, 3 Apr 2021 10:58:34 -0400, Frank Krygowski
wrote:

On 4/3/2021 1:45 AM, Jeff Liebermann wrote:
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.


Maybe. I need to dig through the available literature and do some
testing to see what really happens. You might be correct as drag
produced by the dynamo is reduces at high RPM's by the increased
frequency which presents a higher inductive reactance. On an output
power vs RPM graph, that causes the curve to become "flat" at high
RPM's creating an effective output power regulator. In theory,
inductive reactances do NOT dissipate power. Only resistances
dissipate power. Since the inductance doesn't change, there would be
no change in efficiency. However, there are also saturation effects
in the inductor (windings) which do dissipate power once the current
exceeds the core saturation limit. That should produce heat at high
RPM's. If you have time, try spinning the bottle dynamo at a high RPM
driven by an electric drill and see of it gets hot.

Several times I've touched the outside of my Union bottle dyno after a
long ride. It was never more than very slightly warm. Of course, I was
moving so it was losing heat by convection.
Also, if you have
a motor that can drive the dynamo (or just a spinning bicycle wheel),
try shorting the load (headlight). My guess(tm) is that the motor or
wheel will spin quite easily.

I'm sure I did that some time in the past. I may have notes about it...
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.


Cool. Anything you can share?

No, it was just a brief remark - something like "Oh, I thought they just
wasted all the power above 3W. I'll stop thinking about a constant
velocity drive."
I can think of a variety of CVT
(continuously variable transmission) designs that might be suitable.
I'm not so sure he gave up because he thought it won't work. My
guess(tm) is that it didn't provide a sufficient improvement to
justify the cost and complexity.

I think that's what we're up against in this entire discussion. The
relatively simple systems we have now work very well. It's hard to see
how a lot more complexity and expense will pay off.
Please note that a hybrid battery plus dynamo contrivance would be a
far better proposition. At low speeds, the light operates off the
battery. At higher speeds (i.e. downhill), where there is power
available, it switches to dynamo. In it's spare time, it charges the
battery.

From Sheldon Brown's site: https://www.sheldonbrown.com/dynohubs.html

" I used to have a Dynohub on a tandem, and the bulb consumption was
unacceptable. I solved the problem (and some others) by running the
Dyno's output through a full-wave bridge rectifier and then hooking the
DC in parallel with a 6 volt (5 x 1.2v cell) nickel cadmium battery.
This not only provided light when I was stopped, the Dyno would
re-charge the nicads, and, when we went so fast that the voltage rose
above 6 volts, the low internal resistance of the nicads sucked up the
excess, gaining a bit of extra charge and saving the bulb.

"The rectified output of the Dynohub was always connected to the lights.
There was no way to turn the light off while in motion. It would have
been easy enough to rig a switch for that purpose, but I didn't see the
need. The Dynohub has _very_ low drag."

(There are other articles there on generators, lights, etc. )
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.


I think it was Jay Beattie who suggested the 800 lumen number. I
merely stole it from him. I agree that 800 lumens probably too much.
However, if such a high power dynamo product ever arrives on the
market, there will surely be a lumens war among vendors to see who can
advertise the largest number. At that time, 800 lumens will reserved
for purists and regulatory agencies.

Yep, safety inflation is real.


Since when is being able to see "safety inflation"? Let's go for a night ride sometime, you and your bottle dyno and light, and me and my whatever light I chose. I'll wait for you at the bottom. On flat roads and the bike path through South Waterfront I can get by with a little flea-watt flasher or a clip on flashlight from 1968 -- or my old Wonder Light. But that is not where I do (or did pre DST) most of my riding. Everything involves a descent, often on old broken concrete roads. I've done those on dyno only, and its inadequate except at a creeping pace.

-- Jay Beattie.




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  #112  
Old April 4th 21, 01:24 AM posted to rec.bicycles.tech
[email protected]
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Posts: 1,918
Default Eyc headlight problem

On Saturday, April 3, 2021 at 9:34:50 AM UTC-5, Ralph Barone wrote:
sms wrote:
On 4/2/2021 11:59 AM, Ralph Barone wrote:
sms wrote:
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.


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.


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.


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.


Series being the electricity goes first to one LED and then to the second LED after the first is full.
Parallel being the electricity goes simultaneously to both LED at the same time.

Is parallel bad?
I have my two B&M LED lights in parallel from the Shimano dynohub. Seems to work just fine.
  #113  
Old April 4th 21, 02:28 AM posted to rec.bicycles.tech
SMS
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Posts: 9,388
Default Eyc headlight problem

On 4/3/2021 5:13 PM, jbeattie wrote:

snip

Since when is being able to see "safety inflation"? Let's go for a night ride sometime, you and your bottle dyno and light, and me and my whatever light I chose. I'll wait for you at the bottom. On flat roads and the bike path through South Waterfront I can get by with a little flea-watt flasher or a clip on flashlight from 1968 -- or my old Wonder Light. But that is not where I do (or did pre DST) most of my riding. Everything involves a descent, often on old broken concrete roads. I've done those on dyno only, and its inadequate except at a creeping pace.


Did you ever know someone who believed that every choice they made in
life, including what to buy and what equipment to use (or not use) had
to be validated by trying to get others to do the same thing that they did?

------------------------------------------------------------------------
"Never attribute to malice that which is adequately explained by
stupidity" ─ Hanlon's Razor
------------------------------------------------------------------------
  #114  
Old April 4th 21, 02:35 AM posted to rec.bicycles.tech
SMS
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Posts: 9,388
Default Eyc headlight problem

On 4/3/2021 5:24 PM, wrote:
On Saturday, April 3, 2021 at 9:34:50 AM UTC-5, Ralph Barone wrote:
sms wrote:
On 4/2/2021 11:59 AM, Ralph Barone wrote:
sms wrote:
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.


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.

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.


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.


Series being the electricity goes first to one LED and then to the second LED after the first is full.
Parallel being the electricity goes simultaneously to both LED at the same time.

Is parallel bad?
I have my two B&M LED lights in parallel from the Shimano dynohub. Seems to work just fine.


No, it's my mistake, when you hook up two lamps you put them in series
because you want the voltage of the dynamo to increase. The current is
limited to 500mA no matter what so in parallel you'd still be at 500mA
but you would not be able to increase the voltage by much.

  #115  
Old April 4th 21, 03:01 AM posted to rec.bicycles.tech
John B.[_3_]
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Posts: 5,329
Default Eyc headlight problem

On Sat, 3 Apr 2021 18:28:51 -0700, sms
wrote:

On 4/3/2021 5:13 PM, jbeattie wrote:

snip

Since when is being able to see "safety inflation"? Let's go for a night ride sometime, you and your bottle dyno and light, and me and my whatever light I chose. I'll wait for you at the bottom. On flat roads and the bike path through South Waterfront I can get by with a little flea-watt flasher or a clip on flashlight from 1968 -- or my old Wonder Light. But that is not where I do (or did pre DST) most of my riding. Everything involves a descent, often on old broken concrete roads. I've done those on dyno only, and its inadequate except at a creeping pace.


Did you ever know someone who believed that every choice they made in
life, including what to buy and what equipment to use (or not use) had
to be validated by trying to get others to do the same thing that they did?

------------------------------------------------------------------------
"Never attribute to malice that which is adequately explained by
stupidity" ? Hanlon's Razor
------------------------------------------------------------------------


Keeping up with (or out doing) the Joneses?
--
Cheers,

John B.

  #116  
Old April 4th 21, 01:24 PM posted to rec.bicycles.tech
Roger Merriman[_4_]
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Posts: 346
Default Eyc headlight problem

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:
On Thursday, April 1, 2021 at 7:15:45 PM UTC-7, Frank Krygowski wrote:
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, 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.

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/...77316413_h.jpg I would
hazard a guess that approximately one of those transportational riders has a dyno lights.

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.


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.

Exposure do a higher powered Dynamo.

https://exposurelights.com/products/bike/dynamo-lights/revo-dynamo

I have few of their lights, I like that the lights are well made and can be
repaired!

Beam shape seems to be road ish but not German as you where, I don’t have
problems with blinding folks with the Exposure Strada on low beam.

Roger Merriman

  #117  
Old April 4th 21, 02:44 PM posted to rec.bicycles.tech
Frank Krygowski[_4_]
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Posts: 10,251
Default Eyc headlight problem

On 4/3/2021 8:13 PM, jbeattie wrote:
On Saturday, April 3, 2021 at 4:32:13 PM UTC-7, Frank Krygowski wrote:
On 4/3/2021 12:57 PM, Jeff Liebermann wrote:


I think it was Jay Beattie who suggested the 800 lumen number. I
merely stole it from him. I agree that 800 lumens probably too much.
However, if such a high power dynamo product ever arrives on the
market, there will surely be a lumens war among vendors to see who can
advertise the largest number. At that time, 800 lumens will reserved
for purists and regulatory agencies.

Yep, safety inflation is real.


Since when is being able to see "safety inflation"? Let's go for a night ride sometime, you and your bottle dyno and light, and me and my whatever light I chose.


Fine. We'll do it around here, where the people I have ridden night
rides with all have had lights far less capable than those I use.
Somehow they think they can see with theirs. But they tell me they see
better with mine.

Here's the problem, Jay. "Seeing" is not a binary condition. One can see
better or not as well, depending on various factors - and lumen count is
only one of those factors. It's silly to claim a certain number of
lumens is necessary for everybody. (It's even sillier to claim a certain
number of Watts is necessary, as some others do.)

And demanding ever-increasing numbers _is_ safety inflation. Were you
riding at night ten years ago? 20 years ago? Were you really using 800
lumens then?

On flat roads and the bike path through South Waterfront I can get by with a little flea-watt flasher or a clip on flashlight from 1968 -- or my old Wonder Light. But that is not where I do (or did pre DST) most of my riding. Everything involves a descent, often on old broken concrete roads. I've done those on dyno only, and its inadequate except at a creeping pace.


Yes, I get that. You ride single track through forests, you climb stairs
carrying your bike, you have immensely steep hills and get off and walk,
you have to duck under twigs. I'm not denying that you're a hero.

But claiming or accepting that you're a hero comes with acknowledging
that most others are not!

You keep ignoring that I've said many times that dyno systems are not
what's best for off-road stuff. Could you please acknowledge that I've
said that, and move on? Then maybe we could restrict our discussion to
the conditions in which almost all cyclists actually ride.

Almost all bicyclists - even regular commuters - ride much more normal
routes and surfaces. They don't climb 20% grades on forest paths. They
don't need 800 lumens to see. They don't go blind with 750 lumens, or
even 75. Many of them actually use "flea watt" lights. Perhaps instead
of yelling at me, you should be yelling at them? "GET 800 LUMENS!!"

--
- Frank Krygowski
  #118  
Old April 4th 21, 03:34 PM posted to rec.bicycles.tech
JBeattie
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Posts: 5,661
Default Eyc headlight problem

On Sunday, April 4, 2021 at 6:45:00 AM UTC-7, Frank Krygowski wrote:
On 4/3/2021 8:13 PM, jbeattie wrote:
On Saturday, April 3, 2021 at 4:32:13 PM UTC-7, Frank Krygowski wrote:
On 4/3/2021 12:57 PM, Jeff Liebermann wrote:


I think it was Jay Beattie who suggested the 800 lumen number. I
merely stole it from him. I agree that 800 lumens probably too much.
However, if such a high power dynamo product ever arrives on the
market, there will surely be a lumens war among vendors to see who can
advertise the largest number. At that time, 800 lumens will reserved
for purists and regulatory agencies.
Yep, safety inflation is real.


Since when is being able to see "safety inflation"? Let's go for a night ride sometime, you and your bottle dyno and light, and me and my whatever light I chose.

Fine. We'll do it around here, where the people I have ridden night
rides with all have had lights far less capable than those I use.
Somehow they think they can see with theirs. But they tell me they see
better with mine.

Here's the problem, Jay. "Seeing" is not a binary condition. One can see
better or not as well, depending on various factors - and lumen count is
only one of those factors. It's silly to claim a certain number of
lumens is necessary for everybody. (It's even sillier to claim a certain
number of Watts is necessary, as some others do.)

And demanding ever-increasing numbers _is_ safety inflation. Were you
riding at night ten years ago? 20 years ago? Were you really using 800
lumens then?
On flat roads and the bike path through South Waterfront I can get by with a little flea-watt flasher or a clip on flashlight from 1968 -- or my old Wonder Light. But that is not where I do (or did pre DST) most of my riding. Everything involves a descent, often on old broken concrete roads. I've done those on dyno only, and its inadequate except at a creeping pace.

Yes, I get that. You ride single track through forests, you climb stairs
carrying your bike, you have immensely steep hills and get off and walk,
you have to duck under twigs. I'm not denying that you're a hero.

But claiming or accepting that you're a hero comes with acknowledging
that most others are not!

You keep ignoring that I've said many times that dyno systems are not
what's best for off-road stuff. Could you please acknowledge that I've
said that, and move on? Then maybe we could restrict our discussion to
the conditions in which almost all cyclists actually ride.

Almost all bicyclists - even regular commuters - ride much more normal
routes and surfaces. They don't climb 20% grades on forest paths. They
don't need 800 lumens to see. They don't go blind with 750 lumens, or
even 75. Many of them actually use "flea watt" lights. Perhaps instead
of yelling at me, you should be yelling at them? "GET 800 LUMENS!!"


I'm not yelling at you although I do get tired of the incessant "safety inflation" rant when people buy something that makes it easier for them to ride -- and the implied or overt put-down of anyone who does not ride like you or use your equipment. Oh, and the incessant stories of the unique old guy with [fill in the blank old technology] who beat the uppity racer. Hey, I know a racer who rode a 24 hour race and kicked everybody's ass -- including old bearded guys with dynos.

And I don't know what type of riding most people do, and it really doesn't matter. I know what I do, and I know that my riding is not unique. Unlike you, I am not prescribing a light for anyone but me. And the deal with an 800 lumen light (which is not terribly bright) is that it is also a 300 and 500 lumen light -- and a flasher. A lot of high lumen lights are purchased because they have 4 hour run times at 300 lumens. They're cheap, simple and light.

Personally, I don't care if someone wants more light that a dyno produces, so long as it is pointed down, and the output is reduced in shared facilities. Those things are possible but just not practiced. All cars come with high-beams, and we don't run around ranting about high beams and how low beams should be enough. Instead, we criticize people who are constantly running high beams when it is unnecessary -- like in the MV version of a flat bike lane on a well-lighted street with on-coming traffic.

-- Jay Beattie.

  #119  
Old April 4th 21, 04:58 PM posted to rec.bicycles.tech
SMS
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Posts: 9,388
Default Eyc headlight problem

On 4/4/2021 7:34 AM, jbeattie wrote:

snip

Personally, I don't care if someone wants more light that a dyno produces, so long as it is pointed down, and the output is reduced in shared facilities. Those things are possible but just not practiced. All cars come with high-beams, and we don't run around ranting about high beams and how low beams should be enough. Instead, we criticize people who are constantly running high beams when it is unnecessary -- like in the MV version of a flat bike lane on a well-lighted street with on-coming traffic.


Some sort of automatic dimming when there are approaching bicycles on a
narrow path would be nice. For wider roads, the cyclists will be toward
the right and if the light is properly aimed it won't be shining in the
eyes of oncoming traffic, whether bicycles or cars.

Personally, I'll turn the brightness to the minimum necessary, based on
conditions, but it's the narrower unlit multi-use paths where greater
brightness is necessary so I'll dim the light when there is oncoming
bicycle traffic.

One thing that's annoying is that many DRL strobes use the highest
intensity which is usually unnecessary. Some newer lights have addressed
this with "breathe mode" using lower intensities.

It's the multi-use paths where I have an issue with dynamo lights. These
paths often have a lot of twists and turns as they navigate between
freeways, across railroad tracks, and over waterways. Some of the
overcrossings are not straight ramps but circular ramps. Some turns are
so sharp that they've installed mirrors so you can see oncoming bicycles
and pedestrians. Speeds are slow in many instances and the dynamo output
is too low for night riding on these paths.
  #120  
Old April 4th 21, 05:07 PM posted to rec.bicycles.tech
Frank Krygowski[_4_]
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Posts: 10,251
Default Eyc headlight problem

On 4/4/2021 10:34 AM, jbeattie wrote:
On Sunday, April 4, 2021 at 6:45:00 AM UTC-7, Frank Krygowski wrote:
On 4/3/2021 8:13 PM, jbeattie wrote:
On Saturday, April 3, 2021 at 4:32:13 PM UTC-7, Frank Krygowski wrote:
On 4/3/2021 12:57 PM, Jeff Liebermann wrote:


I think it was Jay Beattie who suggested the 800 lumen number. I
merely stole it from him. I agree that 800 lumens probably too much.
However, if such a high power dynamo product ever arrives on the
market, there will surely be a lumens war among vendors to see who can
advertise the largest number. At that time, 800 lumens will reserved
for purists and regulatory agencies.
Yep, safety inflation is real.

Since when is being able to see "safety inflation"? Let's go for a night ride sometime, you and your bottle dyno and light, and me and my whatever light I chose.

Fine. We'll do it around here, where the people I have ridden night
rides with all have had lights far less capable than those I use.
Somehow they think they can see with theirs. But they tell me they see
better with mine.

Here's the problem, Jay. "Seeing" is not a binary condition. One can see
better or not as well, depending on various factors - and lumen count is
only one of those factors. It's silly to claim a certain number of
lumens is necessary for everybody. (It's even sillier to claim a certain
number of Watts is necessary, as some others do.)

And demanding ever-increasing numbers _is_ safety inflation. Were you
riding at night ten years ago? 20 years ago? Were you really using 800
lumens then?
On flat roads and the bike path through South Waterfront I can get by with a little flea-watt flasher or a clip on flashlight from 1968 -- or my old Wonder Light. But that is not where I do (or did pre DST) most of my riding. Everything involves a descent, often on old broken concrete roads. I've done those on dyno only, and its inadequate except at a creeping pace.

Yes, I get that. You ride single track through forests, you climb stairs
carrying your bike, you have immensely steep hills and get off and walk,
you have to duck under twigs. I'm not denying that you're a hero.

But claiming or accepting that you're a hero comes with acknowledging
that most others are not!

You keep ignoring that I've said many times that dyno systems are not
what's best for off-road stuff. Could you please acknowledge that I've
said that, and move on? Then maybe we could restrict our discussion to
the conditions in which almost all cyclists actually ride.

Almost all bicyclists - even regular commuters - ride much more normal
routes and surfaces. They don't climb 20% grades on forest paths. They
don't need 800 lumens to see. They don't go blind with 750 lumens, or
even 75. Many of them actually use "flea watt" lights. Perhaps instead
of yelling at me, you should be yelling at them? "GET 800 LUMENS!!"


I'm not yelling at you although I do get tired of the incessant "safety inflation" rant when people buy something that makes it easier for them to ride -- and the implied or overt put-down of anyone who does not ride like you or use your equipment. Oh, and the incessant stories of the unique old guy with [fill in the blank old technology] who beat the uppity racer. Hey, I know a racer who rode a 24 hour race and kicked everybody's ass -- including old bearded guys with dynos.
And I don't know what type of riding most people do, and it really doesn't matter. I know what I do, and I know that my riding is not unique. Unlike you, I am not prescribing a light for anyone but me.


Hmm. ISTR you repeatedly telling us how steep, narrow, rough and wet
your riding is. You contrast that with "flatlanders" riding at a slow pace.

You repeatedly refer to your Luxos as a "mood light" and talk about how
bad it is. You extend that to my light, and say you can't believe that
others around here say mine is really good.

But you're still not acting elitist and not disapproving of anyone
else's choice? OK.

(I'll save most of my remarks on safety inflation for a separate response.)

And the deal with an 800 lumen light (which is not terribly bright)...


Really? How long has _that_ statement been true? To what are you comparing?

Personally, I don't care if someone wants more light that a dyno produces, so long as it is pointed down, and the output is reduced in shared facilities.


There actually are reasons people choose not to point their 800 lumen
lights down. Most or all headlights with that output have kindergarten
optics - a round fog of light with a bright spot in the middle. Riders
aim the bright spot down the road for "throw," to see in the distance.

If they even think about aiming it down away from an oncoming rider's
eyes, they find the hot spot is then much brighter on the pavement in
front of them, causing their pupils to contract. They see less well and
don't like that. And the fog of light above the spot can still be
dazzling to oncomers.

This could be fixed. First, as with car headlights, proper optics light
the road evenly with no hot spots and far less upward glare. And it's no
great technological trick to have a properly shaped and cut-off low
beam, while using the simple light for a high beam for when nobody's
around and you're doing gnarly descents through thickets of trees, or
whatever.

But it would require a company capable of at least high school (vs.
kindergarten) optic skills, AND a public smart enough to understand the
problem; or better, a government that understands the problem and makes
appropriate rules.

In this forum, we have an electrical engineer who portrays kindergarten
round beams as superior to properly designed ones. That indicates the
public is unlikely to get smart. And regarding the governement - well,
"FREEDOM!" ... to blind others. "MFFY."

--
- Frank Krygowski
 




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