All RC car batteries must be prohibited to play until the car can not move to charge, when the car speed has become slow signs should be instantly shut down to charge. This is the safest way to protect the battery.

1/14 MJX 14303 Rc Drift Car 2.4G High Speed Drift Rally Truck Hyper Go Brushless 4WD Off-Road RC Cars for Adults for Kids Toys

Extra battery is the 3S 2500mah 25C battery, and the quantity is as you choosed!