Batteries

I haven't looked at the tesla, but in general, LiFePo4 batts operate best in the 10/20% - 80/90% range, afaik. There is a sharp drop off on the power curve at the lower end, but a nice, fairly flat curve between say 20 and 80%.

I'm considering 200Ah's of Lithium, for about 140Ah's of usable power, for example.