G16 slow start and no power going uphill

[Heisenberg]

Hey guys, I hope its ok to start a thread on my first post. I've been searching the site for a few days and have found a few clues, but hoping for some expert advise with this troubleshooting.

I've got a 1998 G16E 36 volt cart that has almost no torque taking off and going up hills. It seems to drive ok if you can get some speed up. Batteries are about 2 years old, and I replaced one recently after I found it to be dry and it failed a load test. The cart used to run pretty good. I had put a rebuilt controller in it when I got it about 3 years ago. I think it's all stock.

I have a wiring diagram and have been looking at the connections and such, but really have no idea how to test anything. I put a volt meter on the motor connections today and got about 6 volts at takeoff and then it climbs as the cart gains speed- up to about 30v before I almost ran off the driveway in the dark while holding a flashlight and a voltmeter... I'll try that again later in the light.

I found the buzzer to be unplugged- plugged it back in- no change and it also doesn't buzz in reverse.

Not sure where to go from here, any ideas?

[Golferdave]

Have you removed all the battery terminals & cleaned them. ?

Did it ever run good with the rebuilt controller?

[Heisenberg]

Originally Posted by Golferdave

Have you removed all the battery terminals & cleaned them. ?

Did it ever run good with the rebuilt controller?

Yes, it ran good at one time with the new controller. I just unhooked all the batteries and cleaned them yesterday. No change.

Today I tested the pedal potentiometer. It has a range of 1300 to 59 ohms at full pedal. Google tells me that it should be 1000 to 0. I wonder if that is off far enough to be a problem? The potentiometer is only a couple years old.

I don't really understand how the speed controller works, but it seems like it provides the ground at varying degrees based on the pedal position. All 4 posts on the motor show 37 volts at rest, and when I throttle it a little, A2 drops to 6 volts or so and doesn't go up unless the cart picks up speed- regardless of the pedal position. I would think that if you floor it from a stop, it would deliver the 37 volts all at once for a quick takeoff. Maybe someone has experience with this?

Another thing to note is that the motor has a distinct squeal when its trying to takeoff. It goes away after you build up a little speed.

[Golferdave]

I think the signal fro the pedal should be 0 , pedal up ,
to pedal down at 1000 ohms

Try charging the batts a few charge cycles
but if all the same since it last ran ok , but batts are older,
I suspect the batt are weak

59 to 1330 ohms would be ok,

[Heisenberg]

Originally Posted by Golferdave

I think the signal fro the pedal should be 0 , pedal up ,
to pedal down at 1000 ohms

Try charging the batts a few charge cycles
but if all the same since it last ran ok , but batts are older,
I suspect the batt are weak

59 to 1330 ohms would be ok,

It's been a couple weeks since I charged the batteries, but I think they usually finish out around 38 volts. I've charged and load tested the batteries several times during this troubleshooting process. I'll charge again tonight and check the finished voltage for good measure

Today I downloaded what was supposed to be the service manual for this cart. Totally useless. It's mostly common sense owners manual garbage and safety warnings. Not a word about how to test components or how things work.

I also removed the motor and took it apart. There were a few grooves where the brushes ride. Right or wrong, I spun the thing and filed the grooves flat, and filed the brushes smooth- hoping for better contact. Other than that, I didn't see anything alarming. It ran exactly the same when I put it back together. I threw a few wrenches across the garage and cussed.

I took the forward/reverse switch apart. The contacts looked brand new, and I found the micro switch for the reverse alarm to be inoperative. The other micro switch works fine, I think it interrupts the power while you shift from forward to reverse.

Lastly, while comparing the wiring to my wiring diagram, I noticed that there is a diode that has been replaced by a jumper wire. It's in the red power wire just before the key switch.

I guess I'll order one of those and see what it does..... I'm about ready to push this thing off of a cliff

[Heisenberg]

39.3 volts it where the batteries level off after charging and letting them sit for a couple hours.

Does anyone know how I can jump full voltage to the motor for testing purposes to see the power comes back?

I think it is a series motor. It has A1, S1, A2 and S2 terminals.

[Heisenberg]

Just thinking out loud here(and that usually gets me in trouble)......But if you've ever called tech support and quickly realized that you're more qualified than the person you're asking to help you......then you know where I am. It happens to me all the time. I'm still down for some help if the right guy comes along, but I may have it figured out by then.

These youtube links should be helpful to the next guy that could test his series motor if he understood how it works.

04A DC Motor Basics, Part 1

36V DC motor test

[Golferdave]

Good batts, connections & cables
Good speed signal to controller
Motors turns, but no torque or speed
No brake drag or flat tires
Not much left to test

Starting to sound like controller

[Heisenberg]

Originally Posted by Golferdave

Good batts, connections & cables
Good speed signal to controller
Motors turns, but no torque or speed
No brake drag or flat tires
Not much left to test

Starting to sound like controller

That's what I'm thinking. I'll try to figure out a way to bypass the controller and just use the solenoid and battery power to test the motor tonight.

[Heisenberg]

Working my way through this I learned that the controller regulates the battery negative connection to the motor to control the speed/current. Today I clipped a jumper cable from the negative side of the battery pack to the A2 post on the motor. The loop doesn't complete until you step on the gas and the solenoid is activated on the positive side of the battery. Stepped on the gas and the cart squealed the tire and drove right up the hill that it wouldn't go up before.

Ordered a controller.