Thanks MTO.
I just asked about LiIon voltage since I was thinking of feeding my segway 45v on each rail instead of the nominal 36. Seems like it will be fine.
The prismatic LiFePO4 or even A123 cells look sweet, but this is a low-budget operation I'm running over here.
Does anyone know if the Segway will run if it gets Power on the correct pins, but no connection on the other pins? It's a longshot. If I could build a battery spoofer that lies about voltage, that might also work. I'd like it to run down to 30v on each rail, to keep using the 9S LiPo arrangement.