Arduino motor shield and RC car using up battery quickly


I've got an RC car that i took apart and replaced the receiver board with an Arduino. Atop it i've stacked a motor shield, connector to the front steering and back motor. I've got 1 9V battery powering the arduino, and one powering the motor shield (I cut the vin jumper so they have independent power.) There's an ultrasonic sensor in the front that tells the car how far it is from an object, and if it's less than some distance, the car backs up, turns then continues straight.

This runs fine on any new 9V out of the package. However, after about 15 minutes, the car becomes very slow, and eventually the battery can't power the car anymore. It also becomes very hot. My guess is that the motors are using to much current. Is this correct? If so, how would I fix it?


That's normal. Why ? BecAuse a 9V battery is only good for multi-meters and smoke alarms. If you are going to use an RC car, you need to learn about RC batteries bacause that' s what RC cars were designed to use. If you are not using an RC battery you should not be using an RC car. They go hand in hand.