My friend acquired an electric scooter that had quite literally fallen off the back of the delivery truck yet when his son sat on the scooter the power was insufficient to pull him around. As I have experience with electronics he asked me to have a look I couldn't find anything physically wrong so concluded that the easiest way was to upgrade the speed controller, it had a YK28 24V 250Watt controller as standard so I purchased a YK31C 24V 500 Watt controller and retro fitted it, but when I turned on the power switch the motor was constantly running. I purchased a new throttle thinking the original was incompatible with the controller but when I installed the new throttle still the same problem. Is there a way of calibrating the throttle to the controller or is there likely some other fault? I am totally new to these speed controllers.
This simple yet effective test will determine which part is causing the problem. Please let us know if you have any questions.