I put 2 new batteries in and it goes down to the red light on the controller and wont go any more if I let it sit for 5 minutes it will go about 20 feet again and then do the same thing again I checked the voltage on the batterries and the voltage w2as about 12.5 volts on both batteries. I put it on the charger and it takes about 1 1/2 hours to bring them up to about 13 75 volts there is no blinking codes on the controller lights any help would be appreciated