Help diagnosing a jerking 2014 CC 48V

[rojo143]

Good afternoon. I need a little help diagnosing the source of a problem on my friends 2014 Club Car Precedent 48V. I have little experience in the world of electric carts but am very mechanically inclined. His cart jerks or hesitates while attempting to accelerate in both FWD or REV. After some research on here It seems to be 1 of 3 possible problems the MCOR, Speed Senor, or the battery pack itself. I started troubleshooting with the speed sensor and that beeps when the cart is pushed forward as it should. So then I began looking at the MCOR and discovered it has already been replaced once before with a Chinese knockoff from amazon so my confidence in this part is not high. I read it out with the tow/run switch in tow mode and both the 2 pin and 3 pin connectors disconnected. I can hear the switch click when the pedal is depressed and am getting continuity on the 2 pin connector. When I read out the resistance with my MM set to 20K ohms on yellow and white wires I am getting 4.64 ohms when not touching the pedal. As I slowly press the pedal down the readings initially jump up to 5.73 then begin to drop and with some consistency once the pedal is to the floor with constant pressure my MM reads 0.15ohms. My question is are these readings normal for an MCOR4? Or should I replace it with a OEM unit? Secondly, I looked at the battery pack and in a static state I was getting a reading of 52.4V, but when I begin to drive it under load and at full throttle the reading will drop to 38.5V. The batteries are 3 years old and were refurbished when he got the cart so seeing that they drop below 50% I assume some new batteries are in order as well but I am looking for some confirmation on what I have found from those who are more knowledgeable on electric carts. Any help is appreciated. Thanks Everyone!!

[WalterM6]

Are you sure that isn't 5.73K ohms? And yes, your batteries are toast.

[rojo143]

Originally Posted by WalterM6

Are you sure that isn't 5.73K ohms? And yes, your batteries are toast.

Yes is would be 5.73k ohms when I initially press the pedal. At rest it is 4.69k ohms and all the way to floor it drops to 0.15k ohms. Sorry for the confusion I figured since I stated the MM was set to 20K ohms it would make more sense then it did after reading it again.

[WalterM6]

What does refurbished mean? Washed out with baking soda? Also, the maximum voltage drop under load allowed would be 8v.

[CP241]

Agreed there is no way to refurbish a battery to new condition. You can “refurbish” old batteries to make them useable temporarily, and I’ve done it many times. But they’re nowhere near “new”. They’re just functional enough to make it work for a while for testing, but need to be replaced.

Check your connections carefully. But you’re gonna need new batteries and new cables probably wouldn’t be a bad idea either.

[Aflyer]

Originally Posted by rojo143

Yes is would be 5.73k ohms when I initially press the pedal. At rest it is 4.69k ohms and all the way to floor it drops to 0.15k ohms. Sorry for the confusion I figured since I stated the MM was set to 20K ohms it would make more sense then it did after reading it again.

Do another test on your MCOR, leave the key off and pump the go peddle 20 times and then drive the car to see if the jerky stuff you talked about in your first post goes away. MI have one that is bad and needs replaced, but doing the peddle pumping keeps that project at bay for a little while.

[rojo143]

Originally Posted by Aflyer

Do another test on your MCOR, leave the key off and pump the go peddle 20 times and then drive the car to see if the jerky stuff you talked about in your first post goes away. MI have one that is bad and needs replaced, but doing the peddle pumping keeps that project at bay for a little while.

I have pumped the pedal upwards of 50+ times and it is still jerky, but I am unsure if the problem is being caused by the MCOR itself or due to the battery pack dropping voltage so far. My buddy has chose to replace the both the MCOR and the batteries, so hopefully that will solve his problem. Thanks everyone for the input.

[Fairtax4me]

Batteries are toast. Replace those first or you're just chasing your tail.

[meimk]

With a “jerky” 48 volt Club Car the first thing I look at is the batteries. That big a voltage drop will definitely make it jerk & shudder.