LED headlights?

Peter said:

Quoted message said:

Both pupil size and retinal sensitivity increase in response to low light levels. In bright
light the pupil size is around 3 mm and after some time in darkness it increases to about 5-7
mm. The maximum size tends to decrease with age. I've never noticed any significant change in
pupil size based on focusing distance. Various drugs, either artificial or naturally produced by
our bodies, will also affect pupil size. The change in retinal sensitivity is over a much larger
range than that produced by changes in pupil size.

Ted replies:

Yes, that is why the variation in pupil size is more for focusing than for light control.

This is the opposite of what I've observed directly or read in other literature. It's clear that
pupil size varies rather dramatically with light level - I can readily observe this effect on my
own eyes while looking in a mirror and it is widely documented (e.g.
exploratorium.edupupil.htmlOpen ↗). And it is in a direction that makes sense for
dark adaptation by allowing more light to enter under dim light. OTOH, variations in pupil size
due to focussing distance appear to generally be very small.

It isn't the opposite of what you observe. How did you observe the effect of pupil size on
image quality?

All right, let's try it this way: Variation in pupil size is more effective for focusing than for
light control.

Quoted message said:

Quoted message said:

The benefit is the same as with any variable aperture: a greater depth of focus is obtained
with a smaller aperture.

Unlike photography where a wide field of view is frequently captured in sharp focus, depth-of-
field is less significant in human vision since only an extremely narrow field is in sharp focus
at any one time.

Focusing of the human eye is an imprecise, dynamic situation, and so the focus is rarely if ever
held at anything close to the accuracy of a camera. Depth of field makes that more tolerable, and a
smaller aperture increases the usable fore-aft lenth of the image.

--
Ted Bennett Portland OR

Benjamin Lewis said:

Ted Bennett said:

Pupil size certainly does change with accommodation, however, and I think it is significant.
Under constant lighting conditions, the pupil contracts as the eye accommodates, or shortens its
focal length, and this is readily observable. The benefit is the same as with any variable
aperture: a greater depth of focus is obtained with a smaller aperture.

This may be a benefit, but is it the cause? Under constant light conditions, with constant pupil
size, more light strikes one's retina under shorter focal lengths (which is why zoom lenses
require larger apertures). Is there any reason to believe that pupil size is determined by
anything other than the amount of light impinging upon the retina? (Not counting dilation induced
by drugs, of course.)

Pupil size is affected by much more than photons. Specifically, pupils contract at shorter focal
lengths, which has the beneficial effect of making it easier to focus at closer distances. That
can't be said to be a result of the amount of light, although more light does make reading easier. I
suspect I may be misunderstanding what you wrote, but with constant light conditions and constant
pupil size, the amount of light in the eye will not change with various focal lengths. The amount of
light is determined by the aperture.

--
Ted Bennett Portland OR

In article <[email hidden]>,

Tim McNamara said:

Tim McNamara said:

Your first point is correct, the pupil changes size much more rapidly than the retina becomes
dark-adapted. The former takes a few seconds, the latter takes about 40 minutes. This gives us
two systems for adapting to variable brightness- one very rapid but of limited range (about 4
times for a minimum pupil size of 2 mm and a maximum of 8 mm), one of great range (1,000 times)
but slow to adapt.

As I point out in a subsequent post, I screwed up the math here. The difference for a 2 mm pupil
vs a 4 mm pupil would be a factor of 16.

It doesn't change what you are saying, but this still isn't right.

Pi r squared is pi in the first case, 4pi in the second. The factor would be 16 for a 4 mm pupil vs
an 8 mm pupil.

--
Ted Bennett Portland OR

Ted Bennett said:

In article <[email hidden]>,

Tim McNamara said:

Tim McNamara said:

Your first point is correct, the pupil changes size much more rapidly than the retina becomes dark-
adapted. The former takes a few seconds, the latter takes about 40 minutes. This gives us two
systems for adapting to variable brightness- one very rapid but of limited range (about 4 times
for a minimum pupil size of 2 mm and a maximum of 8 mm), one of great range (1,000 times) but
slow to adapt.

As I point out in a subsequent post, I screwed up the math here. The difference for a 2 mm pupil
vs a 4 mm pupil would be a factor of 16.

It doesn't change what you are saying, but this still isn't right.

Pi r squared is pi in the first case, 4pi in the second. The factor would be 16 for a 4 mm pupil
vs an 8 mm pupil.

Do either of you read what you write before you hit send?

Just in case it still isn't completely clear: expanding a 2 mm pupil to 4 mm would result in a
factor of 4 times the amount of light admitted; expanding a 4 mm pupil to 8 mm would also result in
a factor of 4 times the amount of light admitted; expanding a 2 mm pupil to 8 mm would result in a
factor of 16 times the amount of light admitted (but is unlikely to happen for typical human eyes).

Ted Bennett said:

Focusing of the human eye is an imprecise, dynamic situation, and so the focus is rarely if ever
held at anything close to the accuracy of a camera. Depth of field makes that more tolerable, and a
smaller aperture increases the usable fore-aft lenth of the image.

I'd go as far as to take your "rarely" a practical "never". I work daily with entertainment lighting
of various kinds and a big rule in designing and focusing a show or event is that it will never look
the same to everyone as "seeing" relies on very much more than pure optical physiology.

Interesting (and educational) as hell to listen in on your perspectives though.

jeffb

Ted Bennett said:

Peter said:

Quoted message said:

Both pupil size and retinal sensitivity increase in response to low light levels. In bright light
the pupil size is around 3 mm and after some time in darkness it increases to about 5-7 mm. The
maximum size tends to decrease with age. I've never noticed any significant change in pupil size
based on focusing distance. Various drugs, either artificial or naturally produced by our bodies,
will also affect pupil size. The change in retinal sensitivity is over a much larger range than
that produced by changes in pupil size.

Ted replies:

Yes, that is why the variation in pupil size is more for focusing than for light control.

This is the opposite of what I've observed directly or read in other literature. It's clear that
pupil size varies rather dramatically with light level - I can readily observe this effect on my
own eyes while looking in a mirror and it is widely documented (e.g.
exploratorium.edupupil.htmlOpen ↗). And it is in a direction that makes sense for
dark adaptation by allowing more light to enter under dim light. OTOH, variations in pupil size
due to focussing distance appear to generally be very small.

It isn't the opposite of what you observe.

Your claim was that the variation in pupil size is primarily for aid in focussing and not for
adaptation to low light levels. [And I note you have yet to give us any reference to support
this claim.]

Yet if I focus on something at a short distance (which you claim will require a small pupil size)
under a low light level, then my pupil size is consderably larger than if I focus on infinity under
a normal light level. This is true for almost all people with some exceptions for people who lack
the normal pupil response to varying light levels. Therefore the pupil size is primarily determined
by light level rather than by focussing considerations. I.e. the observations are the opposite of
what I'd expect if your claim were true.

Quoted message said:

How did you observe the effect of pupil size on image quality?

I have in the past observed the effect of looking through small apertures thereby simulating the
effect of a smaller pupil size. When observing at a distance where the normal accommodation of my
eye lens was still adequate to focus the effect of a reduced aperture is two-fold: 1) the brightness
is reduced as expected since less light is admitted, and 2) the image sharpness is decreased if the
aperture drops below about a mm due to increased diffraction effects. As long as the distance was
one where my lens still operated properly I never observed any overall image quality improvement by
artificially reducing the aperture.

OTOH, when observing at very close distances where the lens no longer has sufficient capability to
reach optimum focus (unfortunately this distance has been increasing for me lately) the reduced
apertures result in improved image sharpness while still reducing the brightness. This is the regime
where the 'pin-hole camera' effect mentioned by Carl becomes important, but note that it's ouside
the range of normal accommodation. However, even in this case the body does not have an effective
mechanism for reducing pupil size for an optimized image. Instead, this is the region where people
instinctively try to shut down the effective size of the eye with the eyelid in an attempt to
marginally improve the image sharpness (commonly referred to as "squinting" although the medical
community reserves this term for improper eye alignment which is something entirely different).

Quoted message said:

All right, let's try it this way: Variation in pupil size is more effective for focusing than for
light control.

The observed pupil variation over a size range of about 2 - 3 is quite effective at light control
since it results in a factor of 4 - 9 variation in the amount of light admitted.* OTOH, focussing is
controlled primarily by the lens and the eye is able to focus over almost as wide a range of
distances when fully dilated under dark conditions as it can when contracted under normal daylight
conditions although there is some reduction in close focussing ability at night. So no, I would not
agree with your new statement either.

I have tried to measure the effect on pupil size of changing the focus distance and was not
successful in seeing any consistent effect - AFAIK, the effect has been observed but is quite minor
compared with the size changes normally seen in response to light level changes.

I have already provided one reference on the relationship between pupil size changes and dark
adaptation and could easily provide more - do you have any quotable or easily-checked reference
that supports your claim that pupil size variations is *primarily* for focussing rather than for
light control? Or your new claim that pupil size is more effective at focussing than at controlling
light levels?

*Sure that's not much compared to the range provided by retinal sensitivity, but a factor of 5 times
as much light is nothing to ignore either. The effective light grasp of telescopes has also gone up
enormously as a result first of improved photo emulsions and more recently with better CCD
technology. But ask any astronomer if it wouldn't be nice to have a new space telescope with 5x the
area of HST or a land observatory with 2- 3x the diameter of Keck. For both telescopes and eyes, the
key to good low-light performance is to both improve the detector sensitivity and to increase the
aperture as much as possible. The dilated pupil makes the eye 5x as effective at dealing with low
light - show me the reference that says variation in pupil size improves the eyes focussing ability
by a factor of 5 or more.

Peter said:

Do either of you read what you write before you hit send?

Yup. Just failed to double-check the math. Consequence of not having had do do this stuff since my
undergrad days.

Ted Bennett said:

In article <[email hidden]>,

Tim McNamara said:

Normal attribution styles would make reading your posts much simpler.

Like this? OK.

Thanks!

Quoted message said:

Quoted message said:

For those who are unfamiliar with the visual system, here some details. <big snip of true stuff>

Quoted message said:

Ted Bennett <[email hidden]> writes:

Quoted message said:

Quoted message said:

Pupil size certainly does change with accommodation, however, and I think it is significant.
Under constant lighting conditions, the pupil contracts as the eye accommodates, or shortens
its focal length, and this is readily observable. The benefit is the same as with any variable
aperture: a greater depth of focus is obtained with a smaller aperture.

While this makes sense from what we know about camera optics, I can't find anything to support
this in any of the sources I've got on my bookshelf. Do you have a reference?

It has been taught in medical school for a while ;-) -actually the mechanisms are not identical,
and in certain diseases the pupil may not react to light but still react to accommodation (You can
search for Argyll Robertson or Adie on the net).

Interestingly enough, it's not in any of my perception textbooks from my undergrad or grad school
days in psychology, although I've only kept Kaufman and several books by James J. Gibson.

Steven M. Scharf said:

with the thermal issues of their LEDs. IF, and it's a big IF, the thermal issues can be solved, and
the optics issues can be solved, then the high efficiency of the LEDs will enable their use in
higher brightness lamps. Portable applications are especially difficult since you can't have a big
fan blowing on them.

Perhaps a *cough* dynamo-driven light of this type could have an air intake on the top of the
headlight, and an exhaust at the rear? Since the LED would only operate when the bicycle was moving,
there'd always be some airflow. I'm a little - no, very - leery of outside contamination, though.

Perhaps instead a metal heatsink could extend from the LED to outside the headlight body?
--
David Damerell <[email hidden]> flcl?

"Frank Krygowski" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

Ron Hardin <[email hidden]> wrote in message

news:<[email hidden]>...

Quoted message said:

Quoted message said:

David L. Johnson said:

I've been curious, from following a couple of sort-of related threads. One guy pointed to a
site that had a 1W single LED light (for $35 or

so).

Quoted message said:

Quoted message said:

Quoted message said:

Now, 1 watt does not seem like much. At the moment I use a 15W Nightrider, but am interested
in something that would last longer and still have enough light.

Are there LED lights that really do the job? How many watts would it

take?

Quoted message said:

Quoted message said:

That would be nearly enough light if it's not generating heat; but the

LED reputation

Quoted message said:

Quoted message said:

for lasting a long time comes from its not drawing much current, which

until now

Quoted message said:

Quoted message said:

has meant not much light either.

Not so. The LED reputation for lasting a long time comes from LEDs being solid state electronic
devices, not high-temperature bits of super-thin tungsten wire.

Oh man, so semiconductors don't produce heat and fail due to over-temperature? The previous poster
was exactly right, "the LED reputation for lasting a long time comes from its not drawing much
current, which until now has meant not much light either." This hasn't mattered when LEDs were used
for indicator lamps, versus a small bulb. Now it matters a lot.

Quoted message said:

Regarding efficiency: The last time I checked, the efficiency (i.e. lumens per watt) of white LEDs
was no better than that of a decent halogen bulb, assuming the bulb was at the optimum voltage or
current. However, LED technology seems to be advancing _very_ rapidly, so I suppose I should check
around again.

The lumens/watt is higher, about 2X, but the candlepower won't be as good due to the optics issues.

Quoted message said:

OTOH, if you decrease an LED's voltage (say, by a battery beginning to die) the LED still does a
good job of pumping out light. For that reason, it gets more light out of a given battery.

Look at the Luxeon data sheet, page 5. For the Luxeon V there is a very narrow range of voltage
where it will operate. As the voltage falls, the forward current decreases rapidly and the luminous
flux decreases as a result.

The solution is to use a DC-DC buck/boost regulator which keeps the voltage constant. There is a
loss of course, which is why they are not used on stuff like lights where precise voltage control is
not necessary.

Zog The Undeniable said:

Dynamo lamps give out a lot more light than their electrical power rating suggests - mine has a 6V
3W bulb [1] but it's about twice as bright as a battery powered 6V 2.4W headlamp. Must be the AC or
something.

It's focussing. Dynamo headlights are of vastly superior design, and do not waste half their output
illuminating the sky and the ground three inches in front of the bicycle.

Quoted message said:

[1] the rear light is a Cateye TL-AU100BS, which is one of the very few UK *legal* LED lights - so
the full dynamo output can go to the front.

I'm afraid it is still the case that no LED light is legal in Britain (in and of itself; a steady
LED accompanying a legal light is legal.)
--
David Damerell <[email hidden]> flcl?

"Andreas Oehler" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

Tue, 13 Jan 2004 06:10:01 GMT, Steven M. Scharf:

Quoted message said:

The Luxeon web site goes into extensive detail about dealing with the thermal issues of their
LEDs. IF, and it's a big IF, the thermal issues can be solved, and the optics issues can be
solved, then the high efficiency of the LEDs will enable their use in higher brightness lamps.
Portable applications are especially difficult since you can't have a big fan blowing on them.

The situation on a bicycle is perfect in this regard: You don't need much light on the front when
stationary and you have lots of cooling air when riding.

The problem is getting the cooling to the place where the heat is being generated. It's not
radiating out the front of the LED, it's radiating out the back. So you have a heat sink in the
back. But you can't follow their recommendation for forced air flow over the heat sink fins, in a
small sealed enclosure. You could mount the heat sink to the metal of the outside of the light and
make the case of the light as a finned heat sink.. Or you could use a heat pipe which is bonded to
the bicycle frame. You're going to have to do active thermal management, reducing the current when
there is a danger of overheating, i.e. when the bicycle is stopped.

I'm pretty sure that the reason that most portable applications are using multiple 1W LED rather
than a single 5W LED goes beyond cost; it's easier to thermally manage 5 lower power LEDs.

Quoted message said:

The combination of a current limited (hub) dynamo with a 700mA Luxeon LED in a metal housing (added
with a capacitor based standlight) sounds promising. Someone still has to develop some really
efficient optics. The small, rotational symmetric plastic things are far from what could be done.

Perhaps. The biggest use of the high brightness LEDs is in "being seen" applications such as traffic
lights and brake lights. Lenses and reflectors to make a projectable beam equal to what you get with
quartz-halogen may be too expensive and heavy for portable applications.

"Zog The Undeniable" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

Dynamo lamps give out a lot more light than their electrical power rating suggests - mine has a
6V 3W bulb [1] but it's about twice as bright as a battery powered 6V 2.4W headlamp. Must be
the AC or

something.

It's not the AC. If you hook the same lamp up to DC or AC the ouput will be about the same. The
problem is that the battery powered 2.4W headlamps are not of as good a design, which is why they
are so inexpensive.

If you look at the higher power lights from the commercial manufacturers you'll see that, except for
HID, they usually use the MR16 or MR11 integrated bulb/reflector lamps. These are magnitudes better
than the reflectors used in the low power battery powered lights. The MR16 and MR11 optics are
avaialble in many different beam patterns from wide flood to narrow spot. The better systems use two
lamps, one for "seeing" and one for "being seen" to minimize wasted light output.

The optics of the higher end dynamo lights are almost as good as what you'll get in an MR11 or MR16
lamp, but the beam pattern is more of a spot (see peterwhitecycles.comheadlights.aspOpen ↗). This
is why you should always have some sort of a "being seen" lamp, with a wider beam pattern, when
using a dynamo to illuminate the road surface. A 5W wide flood and a 10W or 20W spot, would be good.
I.e. the Cygolite Rover has a 6w wide and a 10w narrow beam.

"Steven M. Scharf" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

"Peter Cole" <[email hidden]> wrote in message

<snip>

Quoted message said:

An ideal set up for me would be a low power continuous light augmented with a quick
operating, much higher power light, much like auto high/low beams. I've yet to see one on the
market like that.

These are available. A low power 5 watt light and a high power 20W light in the same fixture, or
in two separate fixtures, but powered by the same battery.

I know it can be done, but I haven't seen it done. I have a dual head light, but it's not simple to
switch, I'd really like something like a car's high beam switch just for high speed descents and
times when oncoming lights wash out my vision.

I'm a EE, and have designed (commercially) a number of light systems, but I don't really want
to screw around with all that, I'd rather just buy something. It's really more of a
switch/control problem.

frkrygow said:

Quoted message said:

Dave wrote:

When I ride on dark country roads, my eyes adapt to the dark quite well. But when I meet the
occasional car, I am blinded temporarily by the lights. This can be pretty scary on a descent
around a curve. Any hints on avoiding this problem?

I hate to interrupt the scientific discussion to deal with practicalities, but here goes! ;-)

Yes, I have a hint. Wear a cycling cap, or some other hat with a bill or visor. when a car
approaches, tip your head forward so the visor just blocks the headlights.

If you're riding without a hat, it can help to close one eye until the glare is gone.

I'll try the one-eye trick tonight if I get the "opportunity." I don't know if I can fit a billed
hat under my helmet in addition to the cold-weather gear that keeps my head warm. If it fits, I
might give that a shot sometime soon.

Thanks for the tips.

Dave

Steven M. Scharf said:

"Frank Krygowski" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

Ron Hardin <[email hidden]> wrote in message

news:<[email hidden]>...

Quoted message said:

Quoted message said:

Quoted message said:

... the LED reputation

Quoted message said:

Quoted message said:

for lasting a long time comes from its not drawing much current, which

until now

Quoted message said:

Quoted message said:

has meant not much light either.

Not so. The LED reputation for lasting a long time comes from LEDs being solid state electronic
devices, not high-temperature bits of super-thin tungsten wire.

Oh man, so semiconductors don't produce heat and fail due to over-temperature?

It's not impossible do abuse an LED and get it to fail. And LEDs that push the envelope do produce
significant amounts of heat. But that's hardly typical. They normally run at MUCH lower temperatures
than an incandescent filament.

Quoted message said:

The previous poster was exactly right, "the LED reputation for lasting a long time comes from its
not drawing much current, which until now has meant not much light either." This hasn't mattered
when LEDs were used for indicator lamps, versus a small bulb. Now it matters a lot.

<sigh> The reputation of LEDs is based on their use for the past 40 years or so. In the typical
applications for the past 40 years, they outlasted equivalent indicator bulbs, _because_ there is
nothing in an LED that's white hot, boiling off atoms and constantly losing thickness.

You can't make a typical incandescent bulb work well without having a super-hot filament. You can't
have a super-hot filament without having it burn out eventually. But you _can_ make an ordinary LED
work well, and last damned close to forever, without getting it hot. This is how it's always been
done, and this is the reason for LEDs reputation.

And it's still true. A properly applied LED will last far, far longer than an incandescent bulb in
almost all ordinary applications.

Quoted message said:

Quoted message said:

Regarding efficiency: The last time I checked, the efficiency (i.e. lumens per watt) of white LEDs
was no better than that of a decent halogen bulb, assuming the bulb was at the optimum voltage or
current. However, LED technology seems to be advancing _very_ rapidly, so I suppose I should check
around again.

The lumens/watt is higher, about 2X, but the candlepower won't be as good due to the
optics issues.

As I said, it's getting better, so I'm not surprised. Still, I'd like to read the source. Where did
you get the efficiency figures?

Quoted message said:

Quoted message said:

OTOH, if you decrease an LED's voltage (say, by a battery beginning to die) the LED still does a
good job of pumping out light. For that reason, it gets more light out of a given battery.

Look at the Luxeon data sheet, page 5. For the Luxeon V there is a very narrow range of voltage
where it will operate.

Would you say the Luxeon V is typical of most LEDs?

--
Frank Krygowski [To reply, omit what's between "at" and "cc"]

In article <[email hidden]>,

David L. Johnson said:

I'm not so much looking for a replacement, as a back-up, for my NightRider.

That's how I use my little cheapo LED light, can't remember the brand, that I got on sale. It's my
"Oh [fertilizer]! It's darker than I expected!" light for daylight savings time when I might be out
later than I expect but don't want to haul the big NR with me. This time of year I just leave the NR
on the bike and if the battery's real low, I turn it off on the minor streets, but my commute's
short enough that I generally remember to keep it charged well enough. For me, the LED is a "be
seen" not "see" light, but there's plenty of streetlights on most of the roads I commute on.

--
Drew W. Saunders

dru (at) stanford (dot) eee dee you

Frank Krygowski said:

A properly applied LED will last far, far longer than an incandescent bulb in almost all ordinary
applications.

Typically 100,000 hours -- 10 times longer than the best incandescents, and 50 times longer than
"good" halogens. This is why they're starting to use LEDs for brake, turn signal, and marker lights
for buses and trucks. They've been using them in traffic lights for decades. No lawsuits from poorly
maintained lights, and no maintenance costs.

Matt O.

Steven M. Scharf said:

"Andreas Oehler" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

The combination of a current limited (hub) dynamo with a 700mA Luxeon LED in a metal housing
(added with a capacitor based standlight) sounds promising. Someone still has to develop some
really efficient optics. The small, rotational symmetric plastic things are far from what could
be done.

Perhaps. The biggest use of the high brightness LEDs is in "being seen" applications such as
traffic lights and brake lights. Lenses and reflectors to make a projectable beam equal to what
you get with quartz-halogen may be too expensive and heavy for portable applications.

I'll bet it's going to go the other direction - smaller lenses and reflectors. Seems to me the size
of the reflector and lens must be scaled to the size of the luminous source, to get good optical
precision. (That's why a fluorescent headlight would need a reflector the size of a bread box.) But
the luminous source of an LED is much tinier than even a halogen bulb filament.

Seems that some sophisticated manufacturing might be able to re-shape the integral lens of an LED to
produce a more collimated beam. (My guess is that Cateye's "Opticube" lens is just doing this after
the fact, so to speak). If that were done, you might be able to get an integrated circuit array of
LEDs putting out a carefully shaped aggregate beam, similar to what you get with a good generator
headlight or good low-powered battery light. It would put the light where it's needed, and not waste
it on the trees overhead. ("Waste" refers to road riding, of course.)

--
Frank Krygowski [To reply, omit what's between "at" and "cc"]

[email hidden] (Bill Cotton) wrote in message news:<[email hidden]>...

Quoted message said:

[email hidden] (B.C. Cletta) wrote in message
news:<[email hidden]>...

Quoted message said:

Quoted message said:

I need to know the DC power plug/jack size that the Night Rider uses. I like to put that size
jack on my 30 LED bicycle light. Radio Shack's most popular size is: Size M Coaxial 5.5mm O.D.
X 2.1mm I.D. I presently uses 6.3mm X 3.0mm to match my notebook computer supply.

the new models use a crappy SureLock or something that is not readily available. the old coax,
+3years ago, varied. my 6-V was 5.5x2.1, the 12-V was smaller type, ukn dimensions. for my
home brews, i used a Molex connector, .063 pins (? i think, the smaller ones).

Thanks, I find that some mannfactures uses various sizes connection to discourage mixing. lights
and changes size and/or types often. I agree that different voltage need to be a different size.

awhile back, i stumbled into an EIJA industry standard for coax power plugs and voltage. applied
here, see ratings: <http://www.smk.co.jp/product_e/pdf/plugjack/ESF311201.pdf>

Quoted message said:

I was planning to use the plug/jack on a LED light to lend to and make a beliver of a Night Rider
user that I know. I will have to loan him the light and power pack.