After riding for a while my cart quits running. When it sits and cools off for a few minutes it starts going again.The batteries are only a couple years old and seem to hold a charge well. As long as you are on flat ground and on and off the cart no problems. Start climbing hills,crossing pastures or riding longer than 20 minutes the quitting problem begins. The controller and selenoid are less than a year old. Motor brushings and bearings were replaced 2 months ago.is this normal? Don't know what else I could replace. Any info would be greatly appreciated!! Also cool website!!