Is my motor bad or my controller

[TBMarineServices]

Hey guys, I’m trying to trouble shoot my 95-00 CCDS. Running a controller test from M- and B+ I only get 5 volts out of the controller with it on the ground but if I get the tires off the ground I get full pack voltage (52v) My cables are updraded to 2g and 4g and I have good 125ah/850cca batteries x4. I’ve tested the solenoid and the f/r switch. Thoughts or maybe another test that will help me determine the issue? On a side note the cart will run occasionally like there never was a problem.

[TBMarineServices]

I’ve run continuity test on the motor between A1/A2 and S1/S2 plus the motor body and everything was fine. I opened the back end of the motor and saw lots of brush dust and what looked like a piece of broken brush. So I took the motor to a starter shop to see if they could replace the brush but they didn’t see any issues with that. They did say it looked like my armature had overheated but I put the motor back on my cart and it ran 10 miles perfectly before failing again.

[Golf cart guy]

Taking it to someone that knows golf cart motors might help you.

[NoleFan4Ever]

Originally Posted by TBMarineServices

Hey guys, I’m trying to trouble shoot my 95-00 CCDS. Running a controller test from M- and B+ I only get 5 volts out of the controller with it on the ground but if I get the tires off the ground I get full pack voltage (52v) My cables are updraded to 2g and 4g and I have good 125ah/850cca batteries x4. I’ve tested the solenoid and the f/r switch. Thoughts or maybe another test that will help me determine the issue? On a side note the cart will run occasionally like there never was a problem.

I hope you meant between the M- and the B- or the Main Pack Neg.....

Make sure the key is on, in FNR in Forward, and the wheels jacked up off the ground. Get the Voltage readings for the following Red probe at M- on the controller and Black probe at the B- or Main Pack Neg:
1) Static Voltage = Just under Pack Voltage (PV) (from precharge resistor)
2) Go Pedal depressed just enough to make main solenoid close = Full PV
3) Go pedal half way down = 1/2 PV or gradually going down as pedal is depressed.
4) Go Pedal all the way down = ~0vdc

If it is erratic or drops a few volts then will not go any further OR jumps back to PV, you have a blown resistor in the back side of the potentiometer or a wiper arm/pad issue.

If you want test the motor do this Continuity Test first. Disconnect the pack and then all the cables from the motor. (Be sure to double wrench every motor post/stud when breaking them lose or you may break them off. Spray them down with penetrating oil prior to doing it).

Get out your DVM and set it to the Continuity setting and:
- Test between A1 and A2 (Beep)
- Test between S1 and S2 (Beep)
- Test between A1 and S1 (No Beep)
- Test between A1 to Motor Case (No Beep)
- Test between S1 to Motor Case (No Beep)

If all those are correct as stated above then you can test the motor:

With all cables removed from the motor, jack the cart up at the rear and connect a jumper from A1 to S1. Then connect 12 or 24 volts positive to A2 and 12 or 24 volts negative to S2. (swap S1 and S2 to change rotation direction) You may want to have a disconnect switch in-line with the power supply as some do and some do not....

And remember that you are only "testing" the motor so you don't want or need to engage it very long - if you feel it is a brush problem, you may have to run it at a low speed for a little while to see it anything drops out. What is tricky here is there will be no torque load on the motor. (Do not run it at high RPM's)

[TBMarineServices]

Thanks Nole.... yes I found a great walk through online (http://www.cartsunlimited.net/ezgo-troubleshooting.html). It covered testing every piece of a series motor setup and have ran all these tests. With the cart off the ground it goes from 0 to 50+ volts on M- and B+ as it should but if I do the same test with the cart on the ground I only get 0 to 5 volts output on the controller. Alternatively M- to B- I start at 52v and drops to 0v with the cart off the ground but only down to 48v with resistance.

[TBMarineServices]

Golf Cart Guy, what fun would that be? I want to learn. “Take it to a golf cart shop” could pretty much be a generic answer most posts on this forum (which is awesome and full of knowledge) Unless of course we are to just trade pics of our carts lol (I kid I kid) I’m certainly not a cart expert but I am a Marine electrician and I regularly work on thrusters which is just a large dc motor. :) I do appreciate your advice though. Thanks.

[WalterM6]

I have good 125ah/850cca batteries x4

This might be your problem. Those batteries are automotive batteries. You need deep cycle batteries.

[TBMarineServices]

Originally Posted by WalterM6

This might be your problem. Those batteries are automotive batteries. You need deep cycle batteries.

They are deep cycle batteries. They are LifeLine AGM 31XTs. I took them off of a 24/48 series/parallel bow SidePower bow thruster. I’ve pulked each battery and tested them with a conductance tester and all of them tested great.

[NoleFan4Ever]

Originally Posted by TBMarineServices

Alternatively M- to B- I start at 52v and drops to 0v with the cart off the ground but only down to 48v with resistance.

Then it sounds like you have your answers so if you did the "Motor" testing as I outlined above and it went forwards and backwards with no noted problems then your controller has failed and is not delivering the amperage (force) needed to move the cart.

[TBMarineServices]

Originally Posted by NoleFan4Ever

Then it sounds like you have your answers so if you did the "Motor" testing as I outlined above and it went forwards and backwards with no noted problems then your controller has failed and is not delivering the amperage (force) needed to move the cart.

Thanks Noles, yes that’s the way I’m leaning too. The controller isn’t delivering the amperage needed when there is a “load” on it. I called a cart shop though to try to run a controller down and the mechanic there felt like it was a motor issue. Do controllers have intermittent failures very often?

Go Gators :)