Swaytronic 11.1V, 7200mah is the maximum that goes in. You can't get it empty. Be sure to program the control carefully, otherwise the gearbox will fail or the motor will overheat. It's not bad to install a fan. The tyres are really soft and go down quickly, so make sure you get a replacement in time. The engine has a calculated 5 Nm. This is sufficient for the vehicle. Sound modules and lights can be connected easily. V8 modules, the Rc4Wd should work.