Well if I got one hour out of the flashlight I would be happy. Mostly intended for use at the lake, camping, etc. So that's why I said around total 3Ah at 24V should be sufficient.
Obviously I could find a 24V DC charger that would work (I saw some mobility scooter chargers), and hide...
Thanks Dave. I would likely use two 12v lead acid batteries for cheapness, and the lighter the better so probably ~3Ah. This brings up another question, will they provide the continuous 3-3.5A needed to power the LED? If I remember correctly, any battery can provide any current required of it...
First off, I am a ME student, and I only know enough about electricity to get myself into trouble. I am looking to build a flashlight using a 100w LED chip, a step up constant-current transformer from 12V (or 24V) to 34V and either one or two 12V batteries (higher voltage to improve efficiency)...