Changed EVERYTHING,,, Need some advice

NEW R4FUN Motor, New R4Fun controller, New 72-12 converter, new PSDM and relativly new batteries… Installed everything tonight and >>>>>

I did a down the street and back run (100yards max) and it was badly lacking power.

At the PSDM I had 73.2V. With my meter clamped on the pos and neg on the back of the PSDM I stepped on the brake and gas, dropped to 61V, let off back to 72V.

I think i may have 1 or more bad batteries. All are well within warranty so I can possibly swap them all out.


BTW, if your keeping track of the progression, NO MORE FLASHING DASH LIGHTS… 99.9% sure it was the PSDM…

Yes, that sounds like a bad battery, or two.

Indicator went to full bars over night, showing full charge, backed out of garage, stepped on the gas peddle and went about 4 miles per hour… In about 100 feet showed one red bar and flashing turtle…
Also still had meter connected, 73.3 at start, 61.1 after 100’… I am going to swap them all…

I am ready to have her back…

Sounds like an ideal time for a lithium upgrade.

did you jump your temp sensor ?

No, how do you do that?

R4F motors dont have temp sensors . So take the 2 wire plug that normally plugs into the motor and jump the 2 wires together . Your Gem is in fault mode without doing that .

I just checked, I did that when I installed the motor, just forgot. The other piece he sends to trick the speed control is also installed.

You have a bad battery . Forget what the dash says . Charge it all the way . Then put you volt meter on each battery . Put it in gear . Hold down the brake pedal and give it some power . The bad battery will have a much lower voltage.

1 Like