using rechargable CR123 to run a 12V system

Right since I'm a mountain biker I've been thinking of making a very bright headlight for it. My brother built up a nice system using bulbs with built in reflectors that run at 12V and runs on a battery which works out at about 12Nimh AA cells. I was wondering if the rechargable CR123 would work since they start out at about 4V. Could I make a few sticks of 3 of these cells in series to give the voltage and the hook up hover many sticks I'd need for the time on the bike (use 3 cells for short trips and save weight). I was thinking of having a 15 and 20watt bulb or 15 and 35watt bulb. Would the cells be fine up to 35Watts?
Would running one 35watt bulb be better then a 15 and a 20? I'm wanting to light up a path not a motorway after all.
Maybe I could be silly and turn on a 15 and 35watt as a high beam? (just for a second or so)

I think you might probably be better off using a 12v Sealed Lead Acid cell so you dont have to worry about buying that many rechargable 123's. Also the SLA can handle a high amp load as the Li-Ion R123's cannot.

Shane

I don't want to use a lead acid pack, They weigh a lot and it would defeat the purpose of building the light.

I could still save a load of weight over a lead acid by running Nimh AA cells

Ive seen little SLA packs at Frys that were real lightweight, if you're thinking about just a Thor battery then yah those are huge, but i dont think you're going to need that kind of amp draw, you can get a little 3 amp hour pack thats about 1 inch thick by about 5 inches long and 3 inches high. *shrugs* but whatever you want i guess.

Shane