Electronics, Lighting, & Gadgets - confusion about leds for commuting w/dynohub

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unterhausen
01-07-09, 12:07 PM
It seems like most of the people that build their own led systems are looking for blinding lights for off-road or high speed use. I am thinking about building up to that level of insanity by starting with something that is as good as the Shimano incandescent light I have right now. I have a DH-3D71 hub.

I was thinking about going with an MC-E or a P7, but I'm not positive that is the best approach for a commuting light. In particular, the MC-E optics don't seem to have caught up, and I don't see all that many DIY P7s. Another problem is the multi-die lights are too bright at full power.

I was thinking about going with some XR-Es, and as simple of a circuit as I can come up with. Am I correct in thinking that if I had 4 XR-E I would have the same amount of light as an MC-E?

If anyone can offer any insight, I'd appreciate it. I'm just trying to get my thoughts together.

Unknown Cyclist
01-07-09, 06:37 PM
Do this:

http://www.pilom.com/BicycleElectronics/triLEDhead.htm

:)
znomit
01-07-09, 07:04 PM
I was thinking about going with an MC-E or a P7, but I'm not positive that is the best approach for a commuting light. In particular, the MC-E optics don't seem to have caught up, and I don't see all that many DIY P7s. Another problem is the multi-die lights are too bright at full power.

I was thinking about going with some XR-Es, and as simple of a circuit as I can come up with. Am I correct in thinking that if I had 4 XR-E I would have the same amount of light as an MC-E?

P7 is parallel wired so no good for dynamo setups. MC-E can be series wired so ideal, though likely too bright for a commuter. A dual XR-E setup is around 300lm which should be plenty (single XRE is likely fine too). More LED means less light at lower speed and/or more complicated wiring.

Heres my simple single XR-E, it s a good place to start and cheap to build. Circuit from Martin at pilom.com (http://www.pilom.com/BicycleElectronics/DynamoCircuits.htm)
http://idisk.mac.com/timonz/Public//singledyno1.jpg.

unterhausen
01-08-09, 12:51 AM
Thanks for both responses. I knew there was something I was missing about the P7.

Zenomit, I was admiring your light on one of the other forums. That's probably something like what I will do. I have some square aluminum tubing. I've seen those square plugs, trying to figure out where.

I'm thinking I will lash something up with the luxeon stars I have. That way I can use it and get some experience.