2008 Precedent jerks after running 20 minutes

[Minnesoootan]

Newbie here! Thanks in advance for any guidance on this one. It has had me stumped for a few weeks.

2008 48v Precendent PQ serial code. 3" RHOX lift, 20x10-12 wheels, Revolution speed magnet installed after issue started. 4 gauge wires everywhere (also installed after issue started). GE Motor. 2017 Trojan T-1275 batteries. Cart fully charges to 50.98 volts.

After driving at pretty much full throttle for 3 miles on pavement (somewhat hilly), the cart will start to jerk. It's not just coasting, it acts like it's hitting regeneration mode for a split second and then takes off. This happens about every 5 seconds at full throttle. If I left off the pedal slightly, it stops for about 30 seconds and then starts again. I have to go slower and slower to keep it from happening until the cart drops into limp mode and we go home very slowly. When I get home, I test the battery pack at about 49.4 volts.

I was thinking it might be a controller issue and thought I could "fool" it with a speed magnet. Nope. Then I checked the motor and it seemed pretty hot after running so thought all cable should be swapped out from 6 gauge to 4 gauge. No help.

This just started happening about 6 weeks ago. I do have a multimeter and a digital clamp meter with min/max so can test amperage draw (largest draw I've seen on a small incline was about 154 amps). Lowest voltage I've seen under acceleration on any one battery was about 11 volts.

If I let it sit and cool for a few minutes, it runs fine for a little while but then starts again. I have done the standard push test for the controller and have reset the OBC.

Anyone have any ideas? I don't want to keep shotgunning stuff. It seems that I've attacked the cheaper/simpler items. Only thing left is controller, OBC, batteries or motor?

Thanks again!

[Qman97]

I had a similar issue with my 2009. I would cruise slow for about a couple miles or so and the cart would start to stutter and/or completely shut off. I checked everything and finally noticed the large metal plate the controller is mounted to was HOT! Really hot!

I ended up replacing the controller and selinoid with the Alltrax setup and I have had no issues since.

Next time it does this put your hand on the metal plate where the controller is and see if it is overheating

[Minnesoootan]

Thanks for the reply Qman. The plate over the controller doesn't get hot at all. It is slightly warm, but barely above body temp.

[basshawk84]

Next time it acts up, put the cart in neutral and work the accelerator pedal up and down real fast for 30-40 times. If you're having an issue with the MCOR, this will clear it up for a period of time.

[Minnesoootan]

I'll give that a shot tonight basshawk. Thanks!

[Minnesoootan]

Tried the MCOR test 4 times tonight during one trip. No luck. Any other thoughts?