Could anyone give us some advice as to improving the batteries in Push n Shove as the ones weve got seem to keep letting us down! The bot is a 4WD pusher wired in parallel with 4 12V drill motors, 2 electronize speedos and 2 12V drill batteries. Wheels are solid rubber 75mm diameter. Wed like a bit more speed and something more reliable (they either run out of charge part way through a battle or get too hot). We dont really want to spend a fortune though!!!