My new to me 2008 ES has problems. I put in 6 new batteries and charged them fully until I got the green light. No faults, everything looks normal but it will only run about 20 feet then dies like it has low voltage. I have 76 volts at the motor controller box inputs. Does this sound like a faulty controller? I hate to just throw parts at it.
I had that problem and my speedo wasn’t working. it was the sensor on the end of the motor “speed sensor” The old and new sensors both checked the same with an ohm meter but all was well when I put the new one on.