there is also a 1.2v cell that is 280mah at jaycar.
could have your car running for quite a while!!!
it is a little larger than the 3v lithium batteries (cr2032) and would require a bit of modification to fit into the body of the car.
the battery is 25dia x 8.8mm
i hooked one up outside the car, but it looked weird so i took it off.
i also tried a 1/3AAA 3.6v battery rated at 43mah, but the runtime was too short.
