Originally Posted by Bottomfeeder

Thanks for all the tips guys. It seems that the battery and charger will be the major cost on this project.

One thing that will be important is a unit I can charge in 8 hrs or less. I had a Cygolite a few years back and stopped using it because the 14 hr charge time made it nearly impossible to use on consecutive nights.

Checked out Batteryspace's purpouse built bike battery - $85 with fast smart charger and connectors. At first I thought I'd like to do better. But when you consider that it will cost me maybe $20 total to make my own light... Well, having a 20W halogen system with a burn time of between 3 and 4 hrs for a little over a C-note is pretty sweet - especially when you consider what the Cygolite or Nite Rider would be charging (pun intended) for that kind of performance.

Thanks again. DanO