LED headlights?

David L. Johnson" wrote in message .. .
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).
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?

I have a Cateye EL-300 (5-LED headlight). Does it do the job? That
depends what the job is.

It is a good backup to my halogen lights with enough light to see by
on familiar routes (or if travelling cautiously). Runs for ages on
4AA's, so you don't have to worry about running out of light after an
hour or two.

Also fine away from other lights in open country (once your eyes
become dark-adjusted you really don't need that much light to see by,
a full moon gives quite enough - bright lights just throw what is
beyond their range into total blackness by contrast - of course, light
polluted areas or dark woods are a different matter).

I use it in conjunction with a strobe flasher as it is focussed quite
tightly and I'm not convinced that it gets me seen very well.

A final point. Power is relevant to run-time, but not directly to
brightness (particularly between different technologies such as
filaments and LEDs). Light output can be equally misleading as how
tightly the beam is focussed will have a dramatic impact on what you
can see. You really have to try a light in your particular sutuation
to see if a light is suitable, there isn't a "one size fits all"
solution in the compromise between run-time, light output and beam
dimension.



Andrew Webster

Hello
I have a question about the following statement:
"Many people also had *no* clue about how to mount and aim a headlight,
putting it above the bars and pointing it at the ground right in front of
the wheel"

It seems you would out-ride your headlight at a very slow speed. I don't
hammer on my early morning commutes, but I need to see at least 5 feet in
front of me to be able to dodge road debris. It seems like pointing the
light in front of the front wheel would allow you to see what you are
running over, not avoid it. How do the rest of you aim your lights?
Jim



"Tim McNamara" wrote in message
...
"David L. Johnson" writes:

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). 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?

I don't have direct experience with riding with LED headlights. I
use a Schmidt generator hub and a Lumotec Oval lamp and find that
perfectly adequate for riding all night long.

At PBP this year I saw many people using LED lights, most of which
cast a very bright and very narrow beam. Many people also had *no*
clue about how to mount and aim a headlight, putting it above the bars
and pointing it at the ground right in front of the wheel. The light
appeared adequate in brightness but too narrow in focus for my
tastes.

A to B Magazine did some comparison tests with night photos comparing
beam patterns; you can check their Web site although I don't think the
article itself is posted. You could get it as a back issue.

http://www.atob.org.uk/

There's another Web site with night photos that you can compare
lights.

http://www.fa-technik.adfc.de/Kompon.../vergleich.htm

Peter White's Web site also has some comparisons between lights.

http://www.peterwhitecycles.com/lightingsystems.htm

Quoth Jim Edwards:

I have a question about the following statement:
"Many people also had *no* clue about how to mount and aim a headlight,
putting it above the bars and pointing it at the ground right in front of
the wheel"

It seems you would out-ride your headlight at a very slow speed. I don't
hammer on my early morning commutes, but I need to see at least 5 feet in
front of me to be able to dodge road debris. It seems like pointing the
light in front of the front wheel would allow you to see what you are
running over, not avoid it. How do the rest of you aim your lights?

If your primary purpose is making yourself visible to other road users,
a high position like this is probably good, but the light should be
aimed pretty much level, so it will shin into the eyes of other vehicle
drivers. (Assuming it isn't such a bright light that dazzling would be
an issue.)

However, for evaluating road surface conditions, debris and the like,
it's better for the light to be mounted low, say halfway up the fork
blade as was formerly common on British bikes.

The lower position causes the bright spot to cover a greater length of
roadway. In addition, it causes road irregularities/debris to cast more
prominent shadows.

You can see my current favorite setups at:

http://sheldonbrown.org/raleigh-comp...front-qtr.html

and: http://sheldonbrown.org/gunnar/pages...r-12-03-6.html

Sheldon "Shadows" Brown
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| it is from looking out a kitchen window. You have to dress |
| up, get out training and when you come back, you then know |
| how cold it is. -Sean Kelly |
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Phone 617-244-9772 FAX 617-244-1041
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Hard-to-find parts shipped Worldwide
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Sheldon Brown wrote:
However, for evaluating road surface conditions, debris and the like,
it's better for the light to be mounted low, say halfway up the fork
blade as was formerly common on British bikes.

The lower position causes the bright spot to cover a greater length of
roadway. In addition, it causes road irregularities/debris to cast more
prominent shadows.

A high mounting works better in that you can see the debris anyway. Covering
a greater length just means that you have the wrong beamshape in the first place.

The reason you want to shine downwards is to distinguish wet spots from potholes.
Both are black to a low angle, but a high angle lights up the interior of a pothole.

I myself have the wrong beamshape and use two Cateye Hl-1500's, one aimed ahead of
the other, the forward one being just high enough to illuminate stop signs. You have
to know they're there even if you don't stop for stop signs, because the other
guy has the right of way, and you need to know that.
--
Ron Hardin


On the internet, nobody knows you're a jerk.

On Sat, 10 Jan 2004 18:42:33 GMT, "rosco"
may have said:

... I have one of these Planet Bike units on order,
and plan to modify it using the 3W Luxeon Star if possible ($13 from
www.elekrolumens.com). If it works out, I'll post my findings.

ITYM www.elektrolumens.com (missed a "t").

They presently seem to be saying that all of the hobbyist LED units
are out of stock; I wonder if that's an indication of anything in
particular.


--
My email address is antispammed; pull WEEDS if replying via e-mail.
Yes, I have a killfile. If I don't respond to something,
it's also possible that I'm busy.
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On 10 Jan 2004 15:39:20 -0800, (B.C. Cletta) may
have said:

(if ya don't know) heat is the killer. here is Willie Hunt's
solution for the 5-W Luxeon Star (i hope it goes under the HBs):
http://www.cs.indiana.edu/~willie/DSCN4177.JPG

Aw, heck, no! Straight up, mounted on an all-black bike, we'd have
less than 24 hours after it hit the road before the news wires would
be alive with reports of a mysterious secret government bicyclist with
his mind-control device antenna...

--
My email address is antispammed; pull WEEDS if replying via e-mail.
Yes, I have a killfile. If I don't respond to something,
it's also possible that I'm busy.
Words processed in a facility that contains nuts.

(Andrew Webster) writes:

Also fine away from other lights in open country (once your eyes
become dark-adjusted you really don't need that much light to see
by, a full moon gives quite enough - bright lights just throw what
is beyond their range into total blackness by contrast - of course,
light polluted areas or dark woods are a different matter).

snip

A final point. Power is relevant to run-time, but not directly to
brightness (particularly between different technologies such as
filaments and LEDs). Light output can be equally misleading as how
tightly the beam is focussed will have a dramatic impact on what you
can see. You really have to try a light in your particular
sutuation to see if a light is suitable, there isn't a "one size
fits all" solution in the compromise between run-time, light output
and beam dimension.

I'll second this. I find that overly bright lights make it
paradoxically more difficult to see at night, especially if very
tightly focused. I think it interferes with dark adaptation, as
Andrew mentions.

A less bright lamp with a wider beam is fine to see by (for me). I've
ridden literally all night on several occasions with a 3 watt rated
lamp (Lumotec Oval). I've been comfortable with this setup going 30
mph down hills.

There are probably other factors, though. Some people don't see as
well in dim light as others do, for example. Ambient light can have
an effect- lots of street lights or oncoming traffic reduce one's
ability to adapt to dim light.

"Jim Edwards" writes:

"Tim McNamara" wrote in message
...

At PBP this year I saw many people using LED lights, most of which
cast a very bright and very narrow beam. Many people also had *no*
clue about how to mount and aim a headlight, putting it above the
bars and pointing it at the ground right in front of the wheel.
The light appeared adequate in brightness but too narrow in focus
for my tastes.

I have a question about the following statement: "Many people also
had *no* clue about how to mount and aim a headlight, putting it
above the bars and pointing it at the ground right in front of the
wheel"

It seems you would out-ride your headlight at a very slow speed. I
don't hammer on my early morning commutes, but I need to see at
least 5 feet in front of me to be able to dodge road debris. It
seems like pointing the light in front of the front wheel would
allow you to see what you are running over, not avoid it. How do the
rest of you aim your lights?

OK, let's start with a brief discussion of perception. Why are we
lighting up the road? To make it possible to obtain information.
What information do we need? We need to be able to see the edges of
the road, the texture of the road surface, objects on the road
surface, and objects that might project into the space above the road
from the side. We also need to be able to see our own movement. As
diurnal organisms, humans are visually oriented to the horizon and the
position of the sun, and as we move we see a sort of "optical flow"
coming at us from a point on the horizon and receding behind us to a
point on the opposite horizon- visual texture that diverges as we
approach and converges as we recede from any point in the environment
(see James J. Gibson, _The Senses Considered as Perceptual Systems_
and _The Ecological Approach to Visual Perception_).

A light mounted high, such as above the handlebars, has to be pointed
downwardly at a more acute angle in order to illuminate the road in
front of the wheel. The road is lit brightly, with a "pool" of light
extending from a foot or two in front of the wheel to maybe 15 to 20
ahead. There is not much illumination of the road ahead, therefore,
including road signs, lane stripes, and objects that might project
into the space above the road. We also don't get much sense of
movement because we cannot properly see the divergence of visual
texture ahead of us (and hence we tend to overestimate our speed when
riding at night).

The lower the light is, the longer the illuminated "pool" because the
beam is more horizontal and closer to the road surface. The pool of
light can still start a foot or so in front of the wheel and extend
maybe 50 feet. You can see the texture of the road better because
this type of lighting creates shadows better and there is less bright
"scatter" coming back at you which permits better dark adaptation
(this is why fog lights are mounted low, usually below the front
bumper). This gives you a more accurate sense of your speed.

My headlight is mounted moderately low, just in front of the fork
crown. The (old?) British standard is to mount the headlight on one
of the fork blades, an even lower placement. The French tended to
mount the light at the front of the front fender or on one side of the
front rack, lower than my placement and higher than the British. I
have seen pictures of the light being mounted at or below the fork
end. There's a tradeoff with such mounting- the wheel throws a shadow
to one side, and one will tend to be turning into the dark when
turning to the side away from the light. My headlight location casts
a shadow directly in front of the bike.

I would also recommend staying away from the clear or translucent
lights, which Cateye in particular sells. The idea is to provide a
360 degree immumination so cars and such can see you- but this of
course will shine in your eyes and prevent good dark adaptation. All
the light should go forward; you should wear reflective clothing and
use a taillight to provide visibility from the side and rear.

Head mounted or helmet mounted lights are an interesting case, tending
to produce a "flat" visual field with inadequate depth cues and a lack
of shadows and texture. On the other hand, wherever you are looking
is illuminated, which is not the case with a fixed-mount light on the
bike. I have a helmet mounted light and don't care for it very much
because of the drawbacks, but if I was doing an off-road night ride
I'd want both a fixed light and a helmet-mounted one. I have also
found it helpful in attracting the attention of drivers.

"David L. Johnson" wrote in message
news
On Sun, 11 Jan 2004 08:33:08 -0700, Mark Atanovich wrote:

If you're looking for something to last longer buy or, better yet, build
yourself a larger battery. It will be some time, if ever, that LED
technology improves to the point of being a serious alternative to the
your
high power (10W) light.

I'm not so much looking for a replacement, as a back-up, for my
NightRider. Any ride over 2 hours in the dark, or, more likely, when I
forget that my battery is on the kitchen counter being charged, I'd rather
have some light than none.

This is exactly how I am using my LED Cateye. Back-up and supplement to my
Nightrider. They claim 170 hours of run time -- I dk if that's true, but I
do know that I've used it all fall and winter, and I haven't had to change
the batteries yet. Compared to three hours run time on my old Road Toad,
that's impressive.

--
Warm Regards,

Claire Petersky
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was you."

David L. Johnson wrote:
-snip-
Are there LED lights that really do the job? How many watts would it
take?

"Zog The Undeniable" wrote in message
...
The Cateye EL-300 passes British Standards for front lights and is
wildly popular over here. Personally I don't think it throws a real
beam, so I'll stick with my dynamo for now.

Bruce Lange wrote:
I would say that for routes you are familiar with, the
EL300 is fine,
-snip-
I'm waiting for is a good LED light designed to work with
dynamos. That would be cool.

I was intrigued.

So I clipped a Cateye EL-300 light to my handlebar and ran a
couple of wires from my dynamo through a diode bridge to it.

Amazing! It's very bright. Brighter than with batteries.
The dynamo-powered EL-300 works fine in both constant and
flashing modes.

http://tinyurl.com/ytd5o

Some things I discovered:
-I could not get a crisp photo while spinning the wheel.

-The light is apparently flashing faster than I can perceive
because only one out of nine photos showed the LEDs lit

-If you try it, note the switch on this model is wired into
the light's circuit board. Most handlebar lamps are
switched at the back, breaking the circuit between
batteries. I actually gave up, ripped it all apart and quit
but then noticed the switch wires and tried again with it
_on_. D'oh!

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