LED bike light, round 2
November 5th, 2008 | Published in general | 5 Comments
Here’s the preview of the 2nd version of my generator-driven LED bike light:
It’s a bigger case than the first one because this model has a 1F capacitor to supply a standlight function. I haven’t had it on the road yet, but in my bench (dining room table) testing, about a minute of spinning the dyno wheel to charge the supercap provided at least a couple of minutes of light from the LED after stopping. Flicker seems about the same, and speed to steady light seems about the same. Hopefully i’ll put a few miles on it in the next day or so for some better numbers.
The case was a PITA, frankly. It’s soldered together from copper plumbing parts, and the problem is that copper is so very good at transmitting heat that soldering one end tended to heat up the other end enough for things to break loose. It was also more labor-intensive than i’d planned and weighs a lot (120 grams on my kitchen scale). And i don’t have a back on it yet, haven’t figured that out.
I decided to include a mount tab on this one too, though i haven’t figured out the best way to put that on the bars yet. It’s a piece of copper-plated steel strap, and unfortunately the holes got mis-aligned while in the vise for soldering. It’s pretty stiff though, hopefully strong enough to last.
November 5th, 2008 at 1:52 pm (#)
Hmm, looks sort of like my Dinotte light except mine is polished aluminum.
Suggestion for the back would be a rubber cane tip that you should be able to pick up almost hardware or drug store.
November 5th, 2008 at 1:59 pm (#)
Why did you choose copper for the housing?
November 5th, 2008 at 2:51 pm (#)
Copper – mainly because it’s pretty easy to manipulate and join with the tools i have, and it does a good job as a heat sink for the LED. Aluminum would be better in a lot of ways (mainly less weight), but you can’t braze or solder it, and i’m trying to avoid glues that might come undone in the wet/cold.
Plus it looks bitchin’.
January 9th, 2009 at 8:57 pm (#)
Can you provide more information on this please.
January 9th, 2009 at 11:15 pm (#)
What do you want to know? It’s powered from a standard Shimano 6v bicycle dynohub. This is my second light, electrically identical to my first light but with the capacitor for a standlight function.
The post about the first light with more info and links is here:
http://wjc.fidean.net/log/2008/05/01/new-project-a-generator-driven-led-headlight/