EZGO runs fine on flat ground but not up a hill

[markm]

I have no hills around my shop so I can't test it to duplicate the customers complaint but he said it runs fine on flat ground but any incline you almost have to get out and push it.

It is a 90s model Ezgo...serial number tag is gone so I can't verify year.

It is a series cart...no Tow/run switch.

Has 3 month old batteries. Ran the discharge machine on it for 1 hour yesterday and all had equal loss so I am going to assume I do not have a bad battery in the pack.

I found an old thread that said to test S1 and A1 on the motor with an ohm meter. I only have a digital and when I did that test and turned the wheel I got nothing on my meter.

Any suggestions what to test next?

[JR_ECE]

Does it have stock tires or oversized? Oversized tires will slow it down on hills if the controller isn't upgraded at least with the series cart I owned. Does the cart have quick acceleration on flat ground from a standstill?

[markm]

Completely stock except for a rear folding seat.

Acceleration from standstill is great.

[JR_ECE]

Hmm. I'm wondering how steep of a hill they are climbing. I had my series cart on a number of streets with various grades and it would slow down up the grade, but it had a little bit larger tires on it so I expected it to lose torque and speed on grades. That said, it wasn't too bad except for really steep grades and when the batteries had lost some charge. I think I would visit the area where this cart is used, and use a GPS to check speed on hills versus flats. Or, have the customer check it.

[JR_ECE]

I'll add that I'm not familiar with the motor test you mentioned, but it doesn't seem like the motor would be a problem if it has plenty of acceleration and runs fine on flat ground. It does make me wonder if cables, F/R switch, or the controller might have a problem. My thought is the incline would draw additional current, and might be exposing poor cables (corrosion, bad crimps, etc) or a heavily worn or corroded/dirty F/R switch. Is it possible the stock controller is weak?? I've read where stock controllers can get weak and go out with over stress caused from over sized tires. IF this is true (have not experienced it), then it seems like with old age or heavy use a controller could wear out/get weak in a stock configuration. Then again, I would expect the acceleration to also degrade unless it's a heavy current draw that causes it. Maybe load the cart with 4 large adults to see if it the cart is slow on flat ground.

Another question. Does it have 3 month old GOLF CART batteries or some other type of battery? I'm assuming it 6 x 6 volts DC.

Hopefully someone with different experience will chime in.

[Golf cart guy]

I have seen where the High speed MOSFETS go bad, runs great on flat ground but wont climb a hill. Rare, but Ive seen it. If everything else checked out, that could be it,

[markm]

Yes it has US2200s.

I know there has to be some other tests to do that I have missed, so hopefully one of the experts chime in.

[scottyb]

Connect a digital voltmeter to the pack. Note the reading. Then watch the meter as you try to race uphill and the cart slows down as described.
What is the highest and lowest readings?

[markm]

I will charge it up tonight and load it on a trailer and take to a hill to test it. Nothing but flat ground around my shop.

Will report back.

[scottyb]

Originally Posted by markm

I will charge it up tonight and load it on a trailer and take to a hill to test it. Nothing but flat ground around my shop.

Will report back.

If it's freshly charged drive a half mile before at rest reading to take the high off pack