Slow cart

[mauistardog]

Ok, got a new old cart. When I got it, it ran slow like 5 or 6 mph. Prior owner gave up on it and thought it was a bad motor or brushes. I do the standard check, cables are new and clean all contact look pretty good. New brakes and they are not rubbing. I volt test the batteries and they seem pretty much toast. I buy a new set and still the cart runs slow. new batteries test good. I pull the motor and check the brushes, they look good and have good contact. I took the motor in to an electric motor shop and the guys look at the motor and brushes. They say the motor looks good and the brushes are fine. They said check my wiring again. and if I want take the motor apart and look for any grounding or shorts, but said if their was, the motor would not run at all. Sorry for the long story, but my questions are :

Would a bad controller cause it to go slow ? most time a bad controller would be no movement. Same question about the solenoid, could the solenoid reduce the amount of voltage going to the motor ? I thought it was either power or no power ? attached is a diagram of my set up.
any advise would be great
aloha
joe

[rabbitreborn]

take a DVOM with aligator clips on the probes. Jack up the rear wheels, put the red probe on the B+, put the black probe on the M-. Press the pedal to the floor. What is the highest voltage the DVOM registers?

[mauistardog]

ok, motor is off right now, and will remount once I get the new brushes. Or... can I run this test without the motor on ? So..set my meter to VDC 200V setting right. B+ and M- is on the Controller right :-) what should the meter show ?

thank you for the help.
joe

[rabbitreborn]

In theory, the test can be done with the motor off, but it is best done with the motor on.

200VDC is correct

B+ and M- are 2 of the 3 posts on the controller, correct.

when fully depressed, the voltage coming out of the controller (as measuered at B= and M- ) should read full pack voltage.

[mauistardog]

Ok, when I put the probes on I got around 34.5 when the pedal is pressed to the floor it goes goes up to 36.1 When I tested my battery pack I get 37.6 not sure what this means.

joe

[rabbitreborn]

Are the batteries fully charged?

once you are certain they are fully charged, put the neg probe on the B- and start probing the power wires from the Battery pack to the controller.
Get the pack voltage.
then get the voltage on the battery side of the solenoid.
next get the voltage on the controller side of the solenoid.
follow that with the reading at the B+ on the controller.
Finally move the Black lead to the M- on the controller (red still on B+ of the controller), put the cart in gear (with Key on and rear whells lifted off the ground), and depress the pedal to take the final reading.

All of those readings should be close to the same (pretty much within a volt from start to finish). If they are, the controller and wiring are ok to that point.

[mauistardog]

Thank you very much for your help. Will try to narrow down the problem. new brushes get here tuesday so hopefully that is the real problem.

aloha
joe