Ideas for the Best Bicycle Light in the World!???

Hi,

I am a relative novice to this LED hacking stuff. So I would really appreciate help in designing the ultimate bicycle light for commuting at night. I've been thinking about using one or two Luxeon star LEDs in conjunction with some sort of rechargeable battery. I would appreciate help and input into the following questions:

1. How many Luxeon LEDs would be needed to brightly light up the road in front of me? Would one be enough, or would I need 2?

2. What type of voltage should I run them at?

3. Should they be direct drive or should I use some sort of resistance in the circuit?

4. Any suggestions on the best type of battery pack to run these?

My ideal light would light up the road, be very small and discrete and be able to be mounted on either the handlebar or on my helmet. Battery life would be at least three or four hours.

Anyway, I would appreciate any ideas or feedback.

Andrew

Can I throw out a totally insane but logical idea re: battery pack?

There has been talk of using camcorder batteries--but on a bike you've got the space...why not go (Somone will have a good reason why not ) with a laptop battery? Just as an example--my old (By computer standards) laptop here has a 10.8 V 3600 mAh LiIon battery. Combine that with a step down and you should be able to get hours of light? Yes? No? Oh---days of light...good point.

I think three is the least, but speed will dictate. There was a post here that said one was enough and he rode cross country on a recumbent with it, but he was going pretty slow sounded like. I go thirty+ mph on a road bike, so five would be my hearts desire. Three of them in series needs six ordinary batteries, so that would be 6AA's in series, no resistors at all. The problem is finding a correct donor flashlight to put them in for a housing. I hate project boxes although I have used them at times. Please see my post

web page

Luxeons do a great job of near-field lighting, but still lack ultimate throw. So, even if you had a bank of 8 nx05-collimated luxeons, you'd only really have great immediate area lighting up to about 30-35 feet in front of you. I've got a modded mini flood light that does exactly this. If you're going really fast, I'm not sure if that's enough.

What I haven't tried yet is using 4 nx05 collimated luxeons and the other focused using 4 acrylic ball lenses. That may cover better forward distances. If you overdrive the luxeons hard, you might be able to cut the number you need by 30-50%, so 4-6 luxeons may well cut it, but IMHO, the anwser lies partially in the optics department.

I'm very interested in this also.

When I commuted to work by bike and also did a lot of mountain biking at night, I built 20 watt light based on a 12V halogen bulb and powered it with various camcorder and RC batteries, and eventually just went with a 10amp motorcycle battery. That still wasn't enough light for me for single-track descents so I got a 50watt 12V halogen food(track lighting bulb). That was enough . Cars would dim their headlights when I was coming around a corner with the 50watt on, but at the price of a 4 lb. battery and sub 2 hour run time.

I was hopeful about modding a Luxeon, and based on my experience with an Arc LS the 1w Luxeon has potential for slow or uphill climbs (probably need 2-3 of them), but for descents and fast road riding they don't have near enough throw. Maybe using the Luxeon for your flood in conjunction with another light having better throw might work.

Now I'm hoping the 5w Luxeons will be the ticket.

Just buy a Light in Motion HID bike light or Cateye Stadium or ....


No, seriously, though. I've been looking into this as well.

I think the way to go would be the 5W with a reflector....no doubt about it.

If 1w luxeons are used, I would use atleast two, if not three...all slightly to moderately overdriven.

But I'm looking for a compact design, so using all these luxeons starts to get bulky.

Yeah, one maybe two of the new 5 watt ls plus a well aligned reflector will give pretty good throwing power. I found somethinglike this out when I put a 1 watter behind this reflector
and I got this beam (at about 10 feet):



You might be looking at some pretty high battery weight if you wanted more than a two of them though...

that sure looks like a energizer DB to me.... but the reflector doesn't look famaliar.

Hello.

I was the one who rode across the US on a recumbent using an ARC LS. A couple of observations though. First the roads that I road on were truely dark and one LS was sufficient at relatively slow speeds. Second, my eyes were fully adjusted to the darkness.

At home when I commute, there is a lot of light pollution so you need something that really shines through the diffusion. Personally, I have used a Cateye Stadium HID light (= 84 watts incandescent) for the last 4-5 years (old style) and it works as advertised. I think that LED still have a few years to go before they can provide the amount of light that most commuters need in urban areas.

If someone can design a 5 watt LS cluster that is the equivelent of a 20 watt incandescent light, that would be the minimum for serious night riding.

my goodness... minimum.... sure would rather go the HID way.

I put 3 1 watt emitters using optics, in series, and run them from 8 AA batteries at 12V. That's 4V per LED, and 1 amp! Under load the batteries go to around 10 v, so I figure 10 watts! A lot of light, but probably not suitable for high speeds.

The 5 watt might be the best shot. Even cyan might work well. The best reflector I've found is in the Garrity Ozark Trail. It is deeper than most reflectors, and captures and projects more of the emitted light into a tight beam, but still gives good side light. How about using the head from this flashlight, and part of the body. Cut the body off, and mount the head on the handlebars, and use a 5 or 6 cell battery pack. I'm pretty sure that would do well for those crazy enough to go fast on a bike at night.

I have a 2 D Ozark Trail, which didn't quite take the 6AA battery pack. How about I hack it up? Anyone interested in testing it. It would have a cyan emitter, though.

Wayne J.

A couple of questions. If I wanted the equivalent of a 15 Watt halogen, how many of the five Watt Luxeons or the one Watt Luxeons would I need to use? Are these even available commercially yet? What is involved in building such a thing? Do I need to create some sort of circuit or can I just use a battery pack? Is there any good guide that would explain what's involved in driving these lights?

By the way, I plan to be riding on the road, not off road, and at moderate speeds (10 to 15 mph). I want a light that is bright enough so that cars can see me, as well as my seeing potential potholes in the road.

I have found that one doesn't need that many LEDs to be visible to cars. On the other hand, to recognize potholes in urban areas on public streets, I think the 15 watt halogen is barely adequate.

I have done extensive night riding under all conditions for more than 15 years and have realized that most bike lights are designed to be seen rather than to see.

I am excited by the 5 watt LS but am concerned not only about luxes but runtime. My original Cateye Stadium is really only good for about 45 minutes of quality light. I would gladly trade some of the watts of output for runtime (as on the NiteRider HID light).

I would be glad to test a LS bike setup.

for city riding I find my 10 watt halogen flood to washout in the sodium street lamps and the 20 to be marginally better for lighting up the road. Go into the bushes however and the contrast is amazing. For straight road riding I sometimes switch out the bulbs for more narrow spot beams which throw alot further.

I also built some led lights - one out of 2 1 watt ls and another out of 30 5 mm white nichias. I can tell you that these are bright to look at. The nichia array was uncomfortable to look at even at a distance of 50 ft away and is easily decernable over 200m (+600 ft). The light output for the user however for both lights is only good for short distances and low speeds. I don't know much about the ability to throw light but one reason for this is that leds are basically equal or slightly more efficient than halogens at producing light. Also unlike halogens, which increase in efficiency with a decrease in bulb life when overdriven, leds decrease in life and efficiency on overdrive. So you can't expect 2 watts worth of leds to put out a huge amount of light as compared to a similar halogen (at present).

I think cost will soon be a factor if you want to get usable light from this project. The led lights I built were made with samples left over from an energy conservation project(free). Nichias can be found for 1-3$ each and the ls 1 watt are around $10. Halogen bulbs can be had for 3-12$.

If you are going to throw in alot of money into this project maybe you might want to consider HID. If you can round up 4 people plus yourself you can split a welch allyn 10 watt developers kit. 5 bulbs and 5 ballasts for $500.

hope they can iron out the 5 watt ls problems sooooooon ! Looking at building a small helmet light. Be great to augment a cheap halogen bar lamp.

I have the 3 LED bike light of which Elecktrolumens is speaking of. The light output is not too bad. It doesn't make daylight of your path, and as was stated, best used at lower speeds. I got a comment on how bright the light was when I passed someone. Actually, when I saw them, I took pitty on them and turned the light off until after I passed. I may try to use an Ozarks Trail light and at least try to use it for one of the three, although, I'm not sure how much better that reflector would be from the collimator.

As was noted, a 'see by' light is much harder to build with LEDs than a 'be seen by' light. I build 'be seen by' lights using 6 (or more if I want exceed with excess) 'Superflux' LEDs from lumileds.

The lumileds site is http://www.lumileds.com/products/list/super_flux_index.html

Craig reviewes these LEDs at http://ledmuseum.home.att.net/spider.htm

You can see his review of a light that I built with these LEDs at
http://www.ledmuseum.org/bike1.htm (note: commercial plug )



Six of these LEDs, _underdriven_ at about 40mA will be more than bright enough to compete with car taillighs and running lights, and 16 of these driven at full power are more than bright enough to compete with car brake lights during the day.

Future-Active sells these LEDs (they are the same crowd that distributes the Luxeons, and Lumileds makes both these LEDs and the Luxeons), but you have to buy a minimum of 60 per color. On the other hand, they cost about $0.60 each, so the investment per lumen is considerably lower than with the Luxeon devices.

-Jon

Does anyone know what the relative light output of a 5w Luxeon (white) would be compared to a 12volt 10watt halogen (MR11 or MR16) or a 15 watt halogen?

have to agree with MY. Have been using the NiteRider HID for over a year now - all types of cycling, but mainly off road. Expensive, but still cheaper than one night in intensive care (don't ask...). The runtime of 4 hours is superb. ±40W output - more than satisfactory. A selectable HID/5W luxeon would be nice for those slow uphill and good tar sections. Would allow even longer battery life.

Hello CP'ers,
Just happen to be an avid cyclist and followed this bike light thread. I normally use a helmet-mounted 12W MR11C halogen 10-degree spot along with a bike-mounted 12W MR11C 15 or 30-degree every time I go out. Each light has it's own 6V 4.0Ah NiMH batery pack for about 2 hours run time, and battery w/light weighs less than 1 pound each. Works rather well for me even with the once-in-a-while 35-45MPH decents. I refuse to go out with only one headlight for safety reasons. (Cars have at least 4 independent filaments, so you can always get home safely even if you lose two!) Naturally, I've been interested in an LS application for cycling, but haven't made any decisions yet. I can say, however, that I'm VERY impressed with my recent acquisition of a Lambda Illuminator, and I'm even considering using it either on the bike or helmet, but haven't tried it yet. At the very least, given it's small size and respectable output, it would certainly suffice as a backup light. I placed the LI on a porch step and viewed it from at least 100 feet, and it looks like maybe an HID! I suspect that some motorists might actually be annoyed by its brightness (be kind to them!). The light is seemingly sufficient by itself for near-field lighting (read:moderate speeds), and I'm considering purchasing a second to double the light output and also satisfy the redundancy requirement. Still have more experimenting (and research) to do.
By the way, those 6V/4Ah battery packs I believe are "A" cells times 5, possibly made by Toshiba. Does anyone know where to purchase these 4Ah "A" size cells? These have killer power density, and oodles of possible applications for LS configurations! Thanks for sharing!

Illuminated

you can get nimh 4/3 A cells @ 4500mah for $6.50 us each0

www.batterystation.com

or cheap nimh d cells 9 ah $7 us each

www.cheapbatteries.com

The 4/3 A is optimized for volume at cost of higher resistance - a concern at high current loading which is not applicable to bike lighting. Of course there are exceptions. A group called team sheep in the uk made a 500 watt bike light.

There is another mailorder called TNC which sells the 4/3 A for $5 each and I will try to post the url when I find it.

Android

If you are still interested in led lights take a look at

www.lumileds.com and look at the spec sheets for the luxeon star products. Then compare to a halogen maker like osram sylvania, ge, or phillips - I think phillips owns lumileds.

one site that I find useful is the welch allyn bulb re rater.

www.walamp.com

you can decrease and increase the voltage and see the corresponding effect on bulb life, current draw, colour temperature and efficiency.

so if the 1 watt ls produces 18 lm and the white 5 watt when it comes out "produces up to 120 lm" = 24 lm per watt then you can compare to the wa
site.

from the wa site a fairly common halogen bulb with a life of 2000 hrs, 3000 K at 12 volts produces 15.7 lm/watt. Overvolt to 13.2 v and see that the bulb life drops to 640 hrs while consuming 23.3 watts but producing 438.6 lm giving 18.9 lm/w.

So for these conditions worse than the 5 watt but slightly more efficient than a 1 watt. Note a 12 volt nimh pack will not read 12 volts for much of the discharge - it is higher and closer to 13 volts.

I am assuming the bullshit is about the same on each site and negates each other.