DynoHubs: What light bulbs/LED emitters?

On Mar 16, 4:11*pm, Tim McNamara wrote:
In article
,
*Dan O wrote:

On Mar 15, 2:09 pm, wrote:

With one exception, I've never been in a place where a legally lit
cyclist is not sufficiently conspicuous. *I've satisfied myself
literally hundreds of times that I'm even more visible at night
than I am in daytime.

WTF?!?

WTF do you mean "WTF?!?" *

WTF do you mean WTF be means WTF?

A bicyclist at night with a headlight and
taillight is more conspicuous than a cyclist riding during the day. *Way
more contrast between a bright light and a dark background.

In total darkness, a condition that does not exist for most cycling
situations. This is a juvenile form of argument, Tim.

And even your basic argument is fatally undermined by the deficiency
that the light must be pretty strong to be seen at the same maximum
distance as a cyclist remains visiblein daylight

Andre Jute
Adult cycling club

On Mar 16, 10:07*am, Andre Jute wrote:
On Mar 16, 4:11*pm, Tim McNamara wrote:

In article
,
*Dan O wrote:

On Mar 15, 2:09 pm, wrote:

With one exception, I've never been in a place where a legally lit
cyclist is not sufficiently conspicuous. *I've satisfied myself
literally hundreds of times that I'm even more visible at night
than I am in daytime.

WTF?!?

WTF do you mean "WTF?!?" *

WTF do you mean WTF be means WTF?

A bicyclist at night with a headlight and
taillight is more conspicuous than a cyclist riding during the day. *Way
more contrast between a bright light and a dark background.

In total darkness, a condition that does not exist for most cycling
situations. This is a juvenile form of argument, Tim.

And even your basic argument is fatally undermined by the deficiency
that the light must be pretty strong to be seen at the same maximum
distance as a cyclist remains visiblein daylight

Andre Jute
Adult cycling club

It really does depend on the light system. I was driving home the
other night, and a cyclist approached from the other direction with
two, forward facing flashing LED arrays -- one on the bars and one on
the helmet. These things were blinding. I thought I had stumbled in
to an alien landing. This sort of retina burning, visible-from-
outerspace display would be far more noticeable to a car enterning
traffic from a side street (the usual culprits in a night time
colision, IMO) than a rider in daylight. This system, however, far
exceeded any legal requirement -- for any conveyance, jet, boat, train
or space ship. --- Jay Beattie.

On Mar 14, 9:05 pm, Andre Jute wrote:

3. Forget a dynopowered rear light of any kind. Even the best are
dangerous to your health. The expensive BUMM ones are not watertight
and the best of the rest, made by Basta (I have one they custom make
for Gazelle but it is basically just an aesthetic variation of their
best rear lamp) and by Spanninga (their Ultra; I have that one as
well) are merely better waterproofed, not more illuminative. I keep
them on my bikes simply because they came with the bikes. Even the
best of the dynodriven rear lights are little glimmers that you can
barely see across the street. None of the dyno-driven rear lights
flash, because it is streng verboten to have flashing lights in
Germany and The Netherlands, their prime markets.

Good advice. I had some long discussions with Dutch manufacturers at
the show about their products (and their lack of exporting to the
U.S.), and especially about lighting. I was very suprised to see some
new higher end Dutch commuter bikes with no dynamos at all, hub or
rim. They told me that there is a trend even in the Netherlands toward
battery powered lights at the mid-range for two reasons. First, the
rim dynamos are too unreliable in terms of wiring and in terms of
being damaged when the bicycles are parked, but the hub dynamos are
too expensive except at the very high end. Second, the lights are only
useful as "being seen" lamps at the relatively slow speeds on the
cycle paths.

4. Get a battery rear light. If you're rich, get a Dinotte rear light
(ask Jay; he has one), if not a Cateye TL-LD1100, which is pricey
enough. There is only one other taillight that is good enough for your
life and that's the Trek Disco Inferno, which is no longer made. The
Dinotte and the Cateye 1100 are *bright*, they cast very substantial
light to the sides as well as the rear, and they flash. Those are the
minimum requirements for good taillights, and they are the only ones
who truly meet them. The Cateye 1100 is bright enough to be seen in
bright sunlight; I use it as a daylight running lamp. It is supposed
to last 200 hours on a set of 2 AA batteries; I don't know how long
the batteries last in hours because I use rechargeables and swap them
out every three or four months or so.


Other than folding bicycles, there were probably more new attempts at
LED lights than any other product at the show, including several LED
brake lights and turn signal lights, including some with wireless
transmitters from a switch on the bars But in all the show, the best
rear light remained the CatEye 1100. DiNotte was not at the show.

There actually is a decent tail light from Blackburn (in terms of
brightness and angle of view) but it suffers from using AAA batteries.

7. Or you might want to considering overvolting a single halogen lamp:
you get far more light and you won't blow a Philips MR16 or MR11
longlife unit --anyway, what do you care if you reduce a 3000 mtbf
lamp to 1500 hours of life if you get nearly twice as much light? The
trick is that you must be able to get them in the 6V versions to work
with your dynohub, and the 6V MR16 or MR11 are not easy to find, at
least not where I live.

Yeah, the poor man's HID system! Have you tried a 5W 6V MR16 on a 3W
dynohub?

"http://www.bulbtown.com/5W_6V_MR16_WITH_LENSE_GX5_3_BASE_p/43243.htm"

8. Or, in LEDs, you can fit as many low consumption LEDs as you can
power. Each LED drops y volts, so the total must add up to what your
dynohub produces or must be regulated. You might want to look into
buckpucks to get the voltage right. Frankly, I wouldn't mess with LEDs
unless I could get the latest and the best, together with some means
of focusing the light correctly, and were also willing to sacrifice an
existing set of lights with hefty, preferably cast ali, shells for
cooling the LEDs. I looked into LEDs and decided that BUMM's Fly IQ
(at the expensive end of their range, which is generally overpriced)
would probably in the end cost less than messing around trying to make
my own.

I was surprised to see so few LED based dynamo lights at the show,
because I incorrectly assumed that you could drive something like a
3W Cree LED from a dynamo hub. You can't. Most of the dynamo LED based
lights were three lower wattage LEDs, and not focused or collimated
all that well. Plus no manufacturer is apparantly willing to spend big
bucks on the bins of the Cree LED that are the most efficient.

The best LED headlamp appears to still be the SolidLight's 1203D.
Interestingly, tthey don't mention the LED type anywhere, nor the
wattage.

9. If you're cheap or poor, consider this. Plenty of RBT dickswingers
will now weight in with how fabulous their BUMM Fly IQ is; I have one
too and it is a good light. However. A couple of halogen 2.4W lamps --
because that is what I had at the time of the test; 2x 3W lights would
do better still -- made as much light as the Fly at any speed over a
crawl and could be better arranged because the two lamps had different
spreads.

There is a mistaken belief by many that an LED based light is
necessarily more efficient than a filament based lamp. This is untrue
for higher power lights. The measures taken to dissipate the heat from
a high power LED lamp are quite incredible. Plus an LED llamp is much
harder to lens properly. There are advantages, such as the longer life
of the LED compared to the filament based bulb, especially in a harsh
environment. You keep hearing how LEDs will soon catch up with HID in
terms of efficiency, and this may happen but it's not going to be
cheap. The LED manufacturers already charge a big premium for the
their most efficient product bins, and you see Cree based lights
specifying which bin the LEDs come from.

10. Lights are the last bicycle frontier. We hear a lot of talk from
the technofreakies about how dynamo lights are now so much better than
they were. But better isn't automatically good enough. The best dyno
front light is still only nearly as good as a 10W MR11 battery light
-- whereas I don't feel comfortable on any aspect of lighting (being
seen, having my space respected, seeing) with anything less than about
25W divided between two lamps. YMMV, of course.

Personally I find MR11 based lamps a waste, because the larger
reflector of the MR16 is much more efficient. In fact the sealed beam
12 volt lamps are becoming one of my favorite halogen lamps because of
the large reflector, light weight, and the lack of a need to build any
funky enclosure.

11. In summary: I recommend the Cateye TL-LD1100 battery rear light,
and two cheap BUMM halogen lights driven off the dynamo at the front
with a homemade switch, supplemented in case of regular commuting or
any strenuous riding circumstances by a rechargeable battery front
light set .

Good advice. I'm finding that for many short, slow rides to the store
that the dynamo lights are sufficient. It's for commuting, especially
at relatively high speed, that the higher power lights are necessary
for optimal safety.

13. Good strong lights are useful in daylight too. The flashing Cateye
1100 persuades a lot of people to slow behind me and to give me a
wider berth than they did before I fitted that light.

Try a Flash Flag. See "http://www.flashback.ca/bicycle.html". You can
probably make something similar. I use these on most of our fleet of
bikes, but I'm working on something better. I don't like the lack of a
good breakaway mechanism. Some sort of replaceable, cheap mechanism is
needed. I was hoping to see something similar to the Flash Flag at the
bike show, but there was nothing.

Per SMS:
Flash Flag. See "http://www.flashback.ca/bicycle.html".

Somebody marketed something like that back in the late
seventies/early eighties called "The Sting".

AFIK, it didn't go anywhere.
--
PeteCresswell

On Mar 16, 7:55*pm, Jay Beattie wrote:
On Mar 16, 10:07*am, Andre Jute wrote:



On Mar 16, 4:11*pm, Tim McNamara wrote:

In article
,
*Dan O wrote:

On Mar 15, 2:09 pm, wrote:

With one exception, I've never been in a place where a legally lit
cyclist is not sufficiently conspicuous. *I've satisfied myself
literally hundreds of times that I'm even more visible at night
than I am in daytime.

WTF?!?

WTF do you mean "WTF?!?" *

WTF do you mean WTF be means WTF?

A bicyclist at night with a headlight and
taillight is more conspicuous than a cyclist riding during the day. *Way
more contrast between a bright light and a dark background.

In total darkness, a condition that does not exist for most cycling
situations. This is a juvenile form of argument, Tim.

And even your basic argument is fatally undermined by the deficiency
that the light must be pretty strong to be seen at the same maximum
distance as a cyclist remains visiblein daylight

Andre Jute
Adult cycling club

It really does depend on the light system. *I was driving home the
other night, and a cyclist approached from the other direction with
two, forward facing flashing LED arrays -- one on the bars and one on
the helmet. *These things were blinding. *I thought I had stumbled in
to an alien landing. This sort of retina burning, visible-from-
outerspace display would be far more noticeable to a car enterning
traffic from a side street (the usual culprits in a night time
colision, IMO) than a rider in daylight. *This system, however, far
exceeded any legal requirement -- for any conveyance, jet, boat, train
or space ship. --- Jay Beattie.

I couldn't agree with you more, Jay. A blinding light is as
counterproductive as an inadequate light. Bicycle lights, front and
rear, should be adequate to the task but not a hazard to other road
users. But on RBT it must often seem to you that you are the last
moderate here; I keep stumbling into entrenched prejudice that leads
to vicious responses on helmets and lights, not to mention motor
pacing... -- Andre Jute

On Mar 16, 2:52 pm, "(PeteCresswell)" wrote:
Per SMS:

Flash Flag. See "http://www.flashback.ca/bicycle.html".

Somebody marketed something like that back in the late
seventies/early eighties called "The Sting".

AFIK, it didn't go anywhere.
--
PeteCresswell

Too bad. I find the Flash Flag to be very effective in having
motorists give me more room. Whether it's because they see me better,
or because they just don't want to risk scratching their vehicle, it's
a simple device that achieves its purpose, including in the daytime
where only a few LED flashers are bright enough to be effective.

On Mar 14, 8:05 pm, bob prohaska's usenet account
wrote:
"(PeteCresswell)" wrote:
Per Hank:
I was a liberal arts major, so I bought a Lumotec IQ Fly , crimped the
spade connectors, and plugged it into my SON. Piece of cake.

Having said all that.... Thanks for the terminology. Googling
"Lumotec" led right to Peter White's page dedicated to generator
lighting.
http://www.peterwhitecycles.com/schmidt-headlights.asp

Bike generators match very well to light emitting
diodes.

The problem wiht LEDs is that the AC, non-regulated voltage out of the
dynamo isn't well suited to driving LEDs without some extra
electronics to convert the AC to DC and to keep the current and
voltage constant. To achieve this at low cost and at high efficiency
is not yet possible. This is why the few good dynamo LED lights are so
expensive.

A filament bulb requires only some over-voltage protection, doesn't
care about AC or DC, and lends itself to more efficient optics.

I wish that there would be some higher power dynamos, even at the
expense of more drag and more weight. All that's needed is enough
power to keep a 3W Cree LED, battery powered light, charged. A 4 cell
Cree LED light that automatically switched between two sets of two
cells (operating on one while charging the other from a dynamo) would
be one solution that would be possible with a slightly higher power
dynamo, and would give the best of both worlds. But you're talking
about a $100 headlight by the time it's at the retail level in
volume.

In article
,
Jay Beattie wrote:

On Mar 16, 10:07*am, Andre Jute wrote:
On Mar 16, 4:11*pm, Tim McNamara wrote:

In article

, *Dan O wrote:

On Mar 15, 2:09 pm, wrote:

With one exception, I've never been in a place where a
legally lit cyclist is not sufficiently conspicuous. *I've
satisfied myself literally hundreds of times that I'm even
more visible at night than I am in daytime.

WTF?!?

WTF do you mean "WTF?!?" *

WTF do you mean WTF be means WTF?

A bicyclist at night with a headlight and
taillight is more conspicuous than a cyclist riding during the
day. *Way more contrast between a bright light and a dark
background.

In total darkness, a condition that does not exist for most cycling
situations. This is a juvenile form of argument, Tim.

And even your basic argument is fatally undermined by the
deficiency that the light must be pretty strong to be seen at the
same maximum distance as a cyclist remains visiblein daylight

Try testing this in reality rather than in your imagination. The
reverse of your position is true.

It really does depend on the light system. I was driving home the
other night, and a cyclist approached from the other direction with
two, forward facing flashing LED arrays -- one on the bars and one on
the helmet. These things were blinding. I thought I had stumbled in
to an alien landing. This sort of retina burning, visible-from-
outerspace display would be far more noticeable to a car enterning
traffic from a side street (the usual culprits in a night time
colision, IMO) than a rider in daylight. This system, however, far
exceeded any legal requirement -- for any conveyance, jet, boat,
train or space ship. --- Jay Beattie.

Which some participants in these discussions would still find to be
deficient lighting in some way.

On Mar 16, 9:00*pm, SMS wrote:
On Mar 14, 9:05 pm, Andre Jute wrote:

3. Forget a dynopowered rear light of any kind. Even the best are
dangerous to your health. The expensive BUMM ones are not watertight
and the best of the rest, made by Basta (I have one they custom make
for Gazelle but it is basically just an aesthetic variation of their
best rear lamp) *and by Spanninga (their Ultra; I have that one as
well) are merely better waterproofed, not more illuminative. I keep
them on my bikes simply because they came with the bikes. Even the
best of the dynodriven rear lights are little glimmers that you can
barely see across the street. None of the dyno-driven rear lights
flash, because it is streng verboten to have flashing lights in
Germany and The Netherlands, their prime markets.

Good advice. I had some long discussions with Dutch manufacturers at
the show about their products (and their lack of exporting to the
U.S.), and especially about lighting. I was very suprised to see some
new higher end Dutch commuter bikes with no dynamos at all, hub or
rim. They told me that there is a trend even in the Netherlands toward
battery powered lights at the mid-range for two reasons. First, *the
rim dynamos are too unreliable in terms of wiring and in terms of
being damaged when the bicycles are parked, but the hub dynamos are
too expensive except at the very high end. Second, the lights are only
useful as *"being seen" lamps at the relatively slow speeds on the
cycle paths.

That's a retrograde step. Both my Dutch bicycles have dynamo-driven
front lights and battery rear lights, a very common arrangement at the
high end, the reason being the problem (aesthetics, reliability) of
wiring a dynamo-driven light at the back. But conceptually, once you
accept that the dynamo lights are being-seen lights, or seeing lights
only in undemanding situations, and that for any demanding use
(including by people with a true value of their own lives) such lights
must be supplemented by battery lights, it makes sense to have dyno-
drive lights front *and* back as backups in case the batteries run
out. I'm sure that if they put their minds to it the bike makers or
lamp makers could solve the problem right pronto. (However, I notice
that Shimano is no longer supplying either the front lamp they used to
list, nor the switch they used to list for dynohubs; I wonder if the
glow has gone off the dynohub market for Shimano.)

4. Get a battery rear light. If you're rich, get a Dinotte rear light
(ask Jay; he has one), if not a Cateye TL-LD1100, which is pricey
enough. There is only one other taillight that is good enough for your
life and that's the Trek Disco Inferno, which is no longer made. The
Dinotte and the Cateye 1100 are *bright*, they cast very substantial
light to the sides as well as the rear, and they flash. Those are the
minimum requirements for good taillights, and they are the only ones
who truly meet them. The Cateye 1100 is bright enough to be seen in
bright sunlight; I use it as a daylight running lamp. It is supposed
to last 200 hours on a set of 2 AA batteries; I don't know how long
the batteries last in hours because I use rechargeables and swap them
out every three or four months or so.

Other than folding bicycles, there were probably more new attempts at
LED lights than any other product at the show, including several LED
brake lights and turn signal lights, including some with wireless
transmitters from a switch on the bars But in all the show, the best
rear light remained the CatEye 1100. *DiNotte was not at the show.

There actually is a decent tail light from Blackburn (in terms of
brightness and angle of view) but it suffers from using AAA batteries.

That makes all of *three* generally available good tail lights... A
shameful situation, I think.

There's also a rather ugly front light from Blackburn that I might us
as a front flasher. But first I want to look into making something
like the BUMM Fly IQ flash, so it can run off the dynohub and be there
in cast I want to use it in steady mode. I'm also wondering if I can
make the Cateye 1100 work off the dynohub for the rear.

7. Or you might want to considering overvolting a single halogen lamp:
you get far more light and you won't blow a Philips MR16 or MR11
longlife unit --anyway, what do you care if you reduce a 3000 mtbf
lamp to 1500 hours of life if you get nearly twice as much light? The
trick is that you must be able to get them in the 6V versions to work
with your dynohub, and the 6V MR16 or MR11 are not easy to find, at
least not where I live.

Yeah, the poor man's HID system! Have you tried a 5W 6V MR16 on a 3W
dynohub?

"http://www.bulbtown.com/5W_6V_MR16_WITH_LENSE_GX5_3_BASE_p/43243.htm"

Thanks for the link. They don't deliver to Europe though. The reason I
haven't tried 6V MR16 is that I can't find any locally or deliverable
for a reasonable price, and in fact have several perfectly good (of
their kind, for their purpose) 6V dyno front lights made by Basta,
Spanninga and BUMM.

8. Or, in LEDs, you can fit as many low consumption LEDs as you can
power. Each LED drops y volts, so the total must add up to what your
dynohub produces or must be regulated. You might want to look into
buckpucks to get the voltage right. Frankly, I wouldn't mess with LEDs
unless I could get the latest and the best, together with some means
of focusing the light correctly, and were also willing to sacrifice an
existing set of lights with hefty, preferably cast ali, shells for
cooling the LEDs. I looked into LEDs and decided that BUMM's Fly IQ
(at the expensive end of their range, which is generally overpriced)
would probably in the end cost less than messing around trying to make
my own.

I was surprised to see so few LED based dynamo lights at the show,
because *I incorrectly assumed that you could drive something like a
3W Cree LED from a dynamo hub. You can't.

No free lunch? I assume it consumes too much current.

Most of the dynamo LED based
lights were three lower wattage LEDs, and not focused or collimated
all that well. Plus no manufacturer is apparantly willing to spend big
bucks on the bins of the Cree LED that are the most efficient.

The best LED headlamp appears to still be the SolidLight's 1203D.

That's *very* expensive, Steven. I looked into the SolidLight and was
tempted, but it will be outmoded before I've even run it in, and then
my money will be wasted.

Interestingly, tthey don't mention the LED type anywhere, nor the

Luxeon 3W from a select bin, I imagine.

9. If you're cheap or poor, consider this. Plenty of RBT dickswingers
will now weight in with how fabulous their BUMM Fly IQ is; I have one
too and it is a good light. However. A couple of halogen 2.4W lamps --
because that is what I had at the time of the test; 2x 3W lights would
do better still -- made as much light as the Fly at any speed over a
crawl and could be better arranged because the two lamps had different
spreads.

There is a mistaken belief by many that an LED based light is
necessarily more efficient than a filament based lamp. This is untrue
for higher power lights. The measures taken to dissipate the heat from
a high power LED lamp are quite incredible. Plus an LED llamp is much
harder to lens properly. There are advantages, such as the longer life
of the LED compared to the filament based bulb, especially in a harsh
environment. You keep hearing how LEDs will soon catch up with HID in
terms of efficiency, and this may happen but it's not going to be
cheap. The LED manufacturers already charge a big premium for the
their most efficient product bins, and you see Cree based lights
specifying which bin the LEDs come from.

10. Lights are the last bicycle frontier. We hear a lot of talk from
the technofreakies about how dynamo lights are now so much better than
they were. But better isn't automatically good enough. The best dyno
front light is still only nearly as good as a 10W MR11 battery light
-- whereas I don't feel comfortable on any aspect of lighting (being
seen, having my space respected, seeing) with anything less than about
25W divided between two lamps. YMMV, of course.

Personally I find MR11 based lamps a waste, because the larger
reflector of the MR16 is much more efficient. In fact the sealed beam
12 volt lamps are becoming one of my favorite halogen lamps because of
the large reflector, light weight, and the lack of a need to build any
funky enclosure.

I looked into those garden lighting decorator types of sealed beams
you recommend but again it was a supply problem.

11. In summary: I recommend the Cateye TL-LD1100 battery rear light,
and two cheap BUMM halogen lights driven off the dynamo at the front
with a homemade switch, supplemented in case of regular commuting or
any strenuous riding circumstances by a rechargeable battery front
light set .

Good advice. I'm finding that for many short, slow rides to the store
that the dynamo lights are sufficient. It's for commuting, especially
at relatively high speed, that the higher power lights are necessary
for optimal safety.

I really hoped that a hub dynamo would be so much better than sidewall
dynamos but it is not so: the light output in my kinds of mild use is
no higher. The truth is that a hub dynamo with even the best lamps
designed for it doesn't make adequate light for any of my nighttime
rides -- I might turn from the shop across the unlit graveyard, or
from a garage which sometimes has a veteran car into the rough tracks
on the estate of a friend, and in both places the spread of light
from dynohub lights, and the difficulty of starting up again after you
stop, make the ride into an unnecessarily stressful adventure.

13. Good strong lights are useful in daylight too. The flashing Cateye
1100 persuades a lot of people to slow behind me and to give me a
wider berth than they did before I fitted that light.

Try a Flash Flag. See "http://www.flashback.ca/bicycle.html". You can
probably make something similar. I use these on most of our fleet of
bikes, but I'm working on something better. I don't like the lack of a
good breakaway mechanism. Some sort of replaceable, cheap mechanism is
needed. I was hoping to see something similar to the Flash Flag at the
bike show, but there was nothing.

I think the Cateye 1100 at last does the business, even in daylight;
if Cateye's next model is as much of an improvement over the 1100 as
the 1100 was over the 1000, I will buy that one too. A guy with a 1000
was passing in the winter here at dusk, very poor visibility. He
immediately noticed my 1100 was stronger. We fitted fresh batteries
from my bulk pack, parked the bikes on the hard shoulder with the
lights flashing and walked back. The 1100 was visible for more than an
additional 150 paces, at which point a curve in the road intervened.
This fellow, a Brit, had thought the 1000 a revelation, very good
indeed on cycling hols he takes all over the world every few weeks
when he can get a cheap flight, but he said he would buy the 1100 next
time he was in a shop. He was the one that pointed out to me that the
key is that the bike lights should still be noticeable under street
lights and in traffic; that a test in pitch dark is an engineering
test but useless as a utility test. My Spanninga Ultra, highly thought
of in The Netherlands, recommended in a Fietserbond test, was on the
same bike as the Cateye 1100 and didn't pass our impromptu test.

Andre Jute
I wouldn't want to be on even a cager's conscience

Per Hank:
I was a liberal arts major, so I bought a Lumotec IQ Fly , crimped the
spade connectors, and plugged it into my SON. Piece of cake.

"(PeteCresswell)" wrote:
Having said all that.... Thanks for the terminology. Googling
"Lumotec" led right to Peter White's page dedicated to generator
lighting.
http://www.peterwhitecycles.com/schmidt-headlights.asp

bob prohaska's usenet account wrote:
Bike generators match very well to light emitting
diodes.

SMS wrote:
The problem wiht LEDs is that the AC, non-regulated voltage out of the
dynamo isn't well suited to driving LEDs without some extra
electronics to convert the AC to DC and to keep the current and
voltage constant. To achieve this at low cost and at high efficiency
is not yet possible. This is why the few good dynamo LED lights are so
expensive.

A filament bulb requires only some over-voltage protection, doesn't
care about AC or DC, and lends itself to more efficient optics.

I wish that there would be some higher power dynamos, even at the
expense of more drag and more weight. All that's needed is enough
power to keep a 3W Cree LED, battery powered light, charged. A 4 cell
Cree LED light that automatically switched between two sets of two
cells (operating on one while charging the other from a dynamo) would
be one solution that would be possible with a slightly higher power
dynamo, and would give the best of both worlds. But you're talking
about a $100 headlight by the time it's at the retail level in
volume.

I thought I might throw out my bikes and just sit down and cry because
the world is imperfect. Instead, I just ride with normal dynamo lights.
Installed once and never given a moment's thought since.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971