Bike lights project

HI,
I am signed up for a 24 hour bike race later this summer and will need some lights, I will need 500-900 lumens for an hour at a time, probably 4 times.
Fancy bike light systems with rechargeable lights go any where from $200 to $1000. I do not need rechargable, as this will probably be the only race like this I will do. Its probably cheaper to build 5 throw away battery packs (maybe not?) was thinking of linking 8 alkaline d cell batteries together for a 12v power source to a 50w halogen bulb but that would probably not give me the lumens or burn time I am looking for so was wondeirng if any of you can suggest specs for a DIY project with LED or HID or even halogen bulb. Ideally, I will mount the battery pack into a water bottle cage mounted on the bike, bottle cage could accomoodate something the size of 2 soda cans or a 20 oz plastic bottle, thoughts, ideas suggestions?thanks

Welcome to CPF, james CT.

The CB&M section has not yielded any replies to your enquiry, so I'll move your thread to our Bicycle section, where I hope you will have more luck.

james CT said:

HI,
I am signed up for a 24 hour bike race later this summer and will need some lights.

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Road race? Single track? Need a helmet light (aimable)?

james CT said:

I will need 500-900 lumens for an hour at a time, probably 4 times. .

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If you have an inexpensive light system that comes with a rechargeble pack, could you recharge it when it isn't being used?

james CT said:

Fancy bike light systems with rechargeable lights go any where from $200 to $1000..

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Since you are talking one time use and resale, one or maybe two MagicShine MJ808's with spare battery packs would do the trick. Check out Geoman as he carries spare battery packs.

james CT said:

I do not need rechargable, as this will probably be the only race like this I will do. ..

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Li-ion rechargables carry more power with less weight, and advantage in a race and more desireable for someone buying them from you after the race. If you can charge between runs, that would reduce how many packs you need.

In the same vein LED's will give you more light per watt of battery power meaning less weight in batteries.

If you want to go DIY in a kit, check out the P7 lights here: http://www.hoffmanamps.com/MyStore/catalog/partsled.htm

He is amenable to questions, he rides these lights, as do his friends.

You can still sell them after, like the MagicShines, but have the pride that you rode your own lights.

Do not go custom DIY for a single time use. Too much time, too much riding on them working, and not enough use to justify the effort.

Someone else will likely have good flashlight suggestions (also resaleable).

If you want to go use a cheap flashlight, I would suggest the following:
dx/sku.22569 It will produce ~600 Lumens for 1.5 hours on a single 18650 battery. (US$ 30.24)

With a mount on your bar, or with some ty-raps strapped to your helmet.
dx/sku.31871 (US$ 2.46)

Buy a charger like "Digital Li-Ion 18650 Battery Charger" dx/sku.6105 (US$ 7.52)
and enough batteries like "UniqueFire Protected 18650 3.7V "2500mAh" Lithium Batteries (2-Battery Pack)" dx/sku.29031 (US$ 7.40/ pair) to power you through the race.

IMO handlebar mounted lights should be an accessory light. Your primary light should be helmet mount b/c it casts less of a shadow due to the higher mount. It's also always pointing where your head is pointing. Sometimes when negotiating slow technical terrain...you turn your bars one way or the other keeping balance...there goes your light.


I would build either a singe SSCp7 light or a triple XP-G / XP-E type of thing. You can easily get a couple of hours on a pack that's waaaaay smaller than your D-Cell ideas. Save you a ton of weight and lotz of light.


Check out Hoffmanamps.com for some P7 ideas. 3.7volts runs it fine.