Don asks: I have a cart that has a Curtis controller 25864605 5 pin and ITS speed control. It has been doing fine when we ride it around the neighborhood at max distance 3 miles. We sometimes have three or four adults on it (it has a rear folding seat). Lately, the cart has been slowing down suddenly. After sitting there a couple of minutes, I could take off but it kept doing the same thing until I get it back home. I would appreciate any information you might give me.
I also read when you are carrying that much weight you should increase the size of the controller. I checked out the batteries, 35V, no loose connections. The solenoid works. What do you think?
Guru: Don, the issue you’re having can be caused by a battery not holding its charge. The 35volts you are reading is low and more than likely drops even lower when you try to run the car.
Run the car until it starts the issue. Jack up the rear of the car. Use a volt meter set on DCV or load tester to check each battery. If you are using a volt meter you may have to press the accelerator pedal and engage the solenoid to see the volt drop under load. You’re looking for the one that drops to a lower voltage than the other batteries. The one that drops lower than the others would be the cause.
Upgrading your controller will help with the extra weight on the car. Address the possible battery issue then consider a controller upgrade to increase your torque.