Small Engine Troubleshooting Problems? Ask a Mechanic Now.
Do you have a voltmeter to check the battery voltage? RXV has the motor brake and the brake has to have a full 48 volts or it will apply without warning. So it is very dependent on the battery voltage staying constant. Not sure why reverse is worse than forward, as they both use the same solenoid to power the brake. The brake is a spring applied, and electrically released brake, so when voltage drops, the spring applys the brake. Check pack voltage, fully charged would be around 54 volts, and each battery , if 6, 8 volts batteries would be close to 8.3 volts, ar with 4, 12 volt batteries , around 13.5 volts. What is the age of the batteries and does the charger run a full charge cycle, around 8 hours?
Voltage drop is the most common problem,followed by the brake solenoid, and the brake itself.
Speed sensor is mounted on the drive motor?
So I would guess that the reader is seeing the motor slow with brake!