I'm pretty sure someone somewhere has already built one, i've gone over the concepts involved and it does seem both practical and possible. The idea is this: electric-powered car that is recharged by several wind-generators(essentially fans on the roof) that recharge the batteries once the car is driven up to speed. Yes i do realize that any energy that is being used for recharging the batteries by the generators is how much extra the motor will have to work to overcome the drag(and consequently using battery power), but as long as the generators are generating enough power to equal what the motor is using to sustain constant speed, then the car could in theory run almost forever, right? The only situations where you would be draining the battery and not recovering the charge are: accelerating and going up hills, and of course, any power lost through heat given off through the wires(no electrical system is 100% efficient). Yes the batteries would eventually die, but you could always recharge them and you'd probably get at least hundreds of miles before you ran out. Any ideas why these kinds of cars aren't being marketed?