I recently bought 2 used V4 Razor Ground Force Drifter karts about 2 weeks ago. One worked, one didn't. The dead one had a weak battery which I swapped out and it came to life. Kids had tons of fun for about 5 sessions.
While I was at work, the kids drove the karts until both stopped working and said they were "out of batteries" (versus suddenly stopped working). They charged them back up and I verified that each 12v battery measured between 12.8v and 13.1v. However, next session, neither kart worked. Power light lights up but both basically "click" and barely move (as in just a momentary thunk of chain tension and no actual movement.
Here are my troubleshooting results so far:
Voltage across both batteries w/switch OFF: 25.4v
Voltage across both batteries w/switch ON (no throttle): 21.1v
Motor to controller connectors are melted and distorted, cannot disconnect
Directly connecting 12v battery to motor: rear wheels spin quickly
Voltage across both batteries w/switch OFF: 26.4v
Voltage across both batteries w/switch ON (no throttle): 26.4v
Motor to controller connectors are NOT melted, look fine
Directly connecting 12v battery to motor: rear wheels DO NOT spin at all
I cannot believe both karts died for different reasons on the same day in the same session. I can't understand how the one with no apparent problems in the wiring has a dead motor, nor can I understand why the kart that worked fine with melted looking wires worked great but now shows a voltage drop when turned ON but has a working motor.
Thank you for the quick response.
I'm curious, is the voltage drop I saw from simply turning on the power switch an expected symptom of a weak battery? I ask because my kids have driven these karts for a minimum of 20 minutes (usually over 30 minutes) per session and all of a sudden, it stopped working. There was no slow degradation of battery life. Also, you didn't comment on the melted wiring I mentioned. It's curious to me that the kart with the potentially weak battery would show the symptom of melted wiring, which I would equate to high resistance somewhere in the system.
Either way, tonight I will swap batteries and motors between the two to see if I can make a working combination out of the potentially good parts.