You can drive an electric car with only two 12v car batteries!

[TheWraith]

17. You're right, it probably is, at least for 35 MPH.

I was ballparking it based on battery-to-wheels efficiency numbers for dedicated electric vehicles. The Tesla Roadster is officially rated at around 265 watt-hours per mile, for instance (although in real-world use it's actually somewhat more efficient, capable of running as low as 194 watt-hours per mile under ideal conditions) and the Nissan leaf is rated at 242 watt-hours per mile (again, potentially going as low as 191).

My assumption was also that a converted car is going to be slightly less efficient on electricity than a dedicated EV, because of not as much attention being paid to the weight of the vehicle, and also less efficiency in a drive train built on the assumption of running off a gas engine rather than an electric motor. So I pegged it at the higher end of the potential estimates.