Controller output voltage slow to build up and then cuts out

mrfixit7

I have tested everything on the cart and it has brought me to the controller or motor. The cart will drive fine sometimes but then completely die. It will start off slowly at first most of the time and will build voltage on M- and B+ slowly and then holds but then it will cut out when driving but not when on jack stands. It will chug sometimes also while it builds up speed after it dies. battery pack has tested good all batteries individually load tested.

I am guessing its the motor brushes or the controller. Anyone have anymore test to guarantee one or the other? please help!! Thanks in advance!

BGW

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bobbycason

What kind of cart?

mrfixit7

Txt with 5 pin controller. Series drive with f/r lever by my leg.

JohnnieB

Measure/monitor between the controller's B- and M- terminals while driving cart. This ought to tell you if the problem(s) is controller/throttle related or high current cable/FNR switch related.

Between M- and B+ you have a series circuit of consisting of 5 high current cables, 10 high current cable connections, 4 motor brushes, motor stator windings, motor armature windings and 4 pair of contacts in the F/R switch, so there are at least 25 possible problem sources. Between B- and M- you have the MOSFETs that pass amps to the motor via the above itemized series circuit, or a single problem source with 2 likely reasons for the malfunctioning. Controller or throttle.

When pedal is pushed just far enough the make solenoid click, there ought to be full battery pack voltage (38.2V when fully charged) between B- and M-.

If not, there is a problem in the high current circuit external to the controller.

If so, press pedal to floor and the voltage ought to decrease to 0V, or very closet to 0V.

mrfixit7

Well it seems to have gone away.... I used to keep the cart outside partially covered, now i have room in my garage and it has a warm/dry home. I think moisture may have been to blame. We will see because i have driven many miles the last two days and no issues...knock on wood.... Thanks for the replies!

handtools

Could be the Molex connector between the throttle and controller.

yurtle

This.

Attached Images

Molex.jpeg (254.5 KB, 0 views)

mrfixit7

So my luck has failed. I backed my cart out of the garage into my yard gave it a quick clean being very careful with the water not too get much wet. dried it off and drove down the driveway and floored it when i got into the road and it just died. Now i have no solenoid click anymore. I replaced the solenoid a while ago and that got it to the working stage its at now. I thought i read that the controller failing could kill the solenoid. any truth in that?

Also, I had cut that molex connector out during prior troubleshooting and permanently connected and used heat shrink to seal them.

mrfixit7

ok so first the solenoid is not an issue i'm an idiot and it was in neutral from pushing it back in garage.

I got it up on jack stands and again the voltage drops slowly on b- and m- from full to zero but when i put it on the ground it won't move it chugs and voltage won't drop below 27 volts.

mrfixit7

Well I gave up and shipped the controller off to get checked/fixed. Only $75 to fix it and free diagnosis. We'll see...