PWM DC Motor Speed Controller, DC 10-55V 60A LED Display Stepless 12V 24V 36V 48V DC Brushed Motor Speed Controller with Adjustable Potentiometer and Forward-Brake-Reverse Switch

I have been using these PWMs with m18 knockoff batteries on 3 different cars. Works great. Make sure you secure the dial that adjusts the speed or it will change as they drive around.