Okay, so I've been recently re-acquainted with NiMH AA batteries, after pretty much giving up on them a while ago. This new breed of NiMH 'hybrid' or 'low discharge' batteries from Sanyo (marketed as Eneloop), Rayovac, and others have a quality that previous NiMH batteries did not; they hold a charge! I think the literature says the will hold like 85% of their charge after 1 year.
So, my next question is whetheror not these could be a viable EV battery.
1.2V per cell, 2000mAH, discharge rate up to 4000mA, weighs 27g.
40 cells => 48V, 2AH, weight of 1080g (x10=20AH, 21600g or 47.62lbs)
Does this add up correctly? While this is like SLA, maybe there are version that are lighter?
http://www.eneloop.info/uploads/media/Datasheet_-_HR-3UTG_01.pdf (huh, called 'Twicell' on the spec sheet)