I have a 2xAA 5v mod using a PTN04050C booster.. just use 2 tantalum 100uf caps on the booster, run the output through a 3A horn switch to the atty connector, put the PTN04050C below the horn switch and use AW IMR14500 batts. Works sweet, up to 4h run time for me on each IMR14500 batt. Under a load its around 4.8v. I also installed a fire LED, and when the batts get low it'll start to flicker so you know when to change them out without damaging the IMR's, not to mention the booster will cut out before the IMR's get too low. Been running on it for over 6 months now and it works as good as the day I built it. I use SR Boge cartos on it (about 3.2 ohms).
Spliner