I've already had about all the fun I can stand with the review thread. Now I only monitor it hoping it can surpass the helmet threads. Surely, a more important subject.
Some Evil Vile Creature (me) left my headlight on and, once again, the batteries are dead. What's even dumber, it's on a low speed electric bike that carries a ton of excess power for one stinking bulb. I need to order in a 36V bulb and wire it directly into a switch drawing power from the main system. Then the problem of batteries is a bust.
Hmm. AFAIK, 36 Volt bulbs aren't easy to find!
You could look into wiring a voltage regulator of some sort to drop voltage to the headlight. Some types might be lossy, but a pulse width regulator could be very efficient. See http://www.cs.indiana.edu/~willie/lvr.html for what's probably the most famous.