i wired idea would be how about u replace every wheel with a battery and put rubber arounf the battery for grip and then have little contacts ( like battery contacts inside the body under PCB) that go on the batteries tips and then wire it in series and then put it to the pc board and there u go!
At first glance, it seems possible. Although it'd be hard to rig some kind of inductive pickup for the outside contact points of the cells, assuming you used an "Axle" to connect the other side of the cells in the rear. The front would be a whole other story if you wanted steering. Possible or not, I doubt it'd be worth the effort.