One page describes it as having 6040 sub-C NiMH batteries. A typical capacity and weight for one of these might be 55g and 3Ah at 1.2v. That is equivalent to 65Wh per kg, or 65kWh per ton(ne). 6040 of those would weigh 332.2kg, or 744lbs, and stores 21.7kWh. (And, according to an online price I found with it, cost a shade over $16,000!)
A typical small family car might do 4 miles to the kWh on the motorway, or 5 miles per kWh on normal roads, so putting this battery in a small family car would give you 87 miles on the motorway or 104 miles on normal roads. It would certainly get me to work and back.
However, the car looks like it is much slipperier than a typical car. Assuming that at 245mph the main resistance is air resistance, the required power at 80mph will be less than 4% of the power at 245mph (back to Bernoulli's Theorem: the force is the square of the speed, so the power is the cube of the speed). So the 300kW of motors could be replaced with 12kW of motors, and if a 12kW motor gives 80mph, the car does 6 2/3 miles to the kWh at this speed. So its range at 80mph can be estimated at 145miles at motorway speeds; and given that it'll only need 4kW at 55mph, it gets 13 3/4 miles range to the kWh, so at this speed it's total range will be nearly 300 miles.
I still don't think it'd be practical for going down the shops, though. It doesn't look very "street legal" to me.
