2001 DS won't move after sitting

njncdmjt

I have a 2001 48V DS that doesn't respond to the accelerator after the cart sits for a little while. (A little while means anything more than about 5-10 mins.)
It will "wake up" only after pumping the accelerator several times. After it's back to life, it works normally.

Here's a little background info...

I recently upgraded to a 4 ga cable set.
The batteries are Interstate (2010), and they all test ok with hydrometer and take a charge well. Voltage looks good at rest around 50v, but that's off memory. I can confirm if needed.
It still has the stock controller and motor, which judging by the original shape of the cart, have a lot of (rough) hours.
I do think by OBC is shot because my charger clicks on immediately upon inserting the plug, but I don't think that's causing this issue. I have to keep an eye on my charger to prevent overcharging.
The solenoid clicks when the accelerator is pressed, even when the cart is not responding after sitting.
All limit switches on the F/R switch test successfully.
The accelerator position sensor tests successfully with a voltmeter.
The F/R (lever type) switch was cleaned up nicely when the cables were replaced. I don't think that's the culprit.

I noticed the problem got a lot worse after Halloween where we got a little creative and rode about 5 adults on the cart for an extended period.

When the cart is running, it is a bit slow and seems under-powered. Maybe I'm running @ 9mph?

Any thoughts? Brushes going bad?

Many thanks in advance. Happy New year

BGW

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scottyb

2 things happen when you are pumping the peddle on an electric cart.
1. the micro switches are being triggered.
2. the throttle position indicator (MCOR) is being activated.

Make the cart not work for testing:
Jack one rear wheel off the ground for safety.
Check all the micro switches for power in and power out... if the solenoid is clicking they are good.
If solenoid clicks and cart won't go check the peddle linkage to the MCOR under the cart.
If linkage is good, check MCOR output with voltmeter per manual.

njncdmjt

Thanks for your reply.

The micro switches are working, and the solenoid is clicking upon depressing the accelerator.

As usual with intermittent problems, I'm unable to duplicate the condition now, but I think it will act up again in another hour or so.

The way I'm checking my MCOR is by placing the negative end of my voltmeter on battery 1 negative post (same line that passes through the OBC), and the positive lead attaches to the yellow wire on the controller.

The cart is working at the moment, and I'm getting just over 7V with the pedal to the floor. Would you recommend that type of test? I can try resistance checks too, but the voltage test to the controller should be the easiest method I would think. I'll run the same test when the condition returns.

njncdmjt

Signs are starting to point to a faulty MCOR. I've been rather unsuccessful in duplicating my exact condition, but with my voltmeter attached, I'm seeing a dead spot in the voltage on the yellow wire at about half throttle. Also, I'm only seeing about 5.5 volts now at full throttle, where I was previously seeing about 6.5 (not 7V as previously stated).

Another thing to note is this MCOR had a chunk missing from one corner leaving some of the circuitry exposed to the elements.

njncdmjt

Finally got the cart to act up again, and found that I was getting expected voltage at the yellow wire on the speed controller. It was a little low, but should have been enough to turn on the motor. 0v to approx 5.75v when fully depressed.

Next I tested for any voltage going to the motor from the controller. I ran the positive lead only meter to the green cable at the controller, which is on the same circuit as the solenoid, and the negative lead to the blue cable.

When the cart was not responding to the pedal, there was 0v on the meter. After some pumping of the accelerator, the cart came to life and the meter started showing voltage. This would lead me to a bad controller, IMHO.

Any additional input or suggestions are appreciated.
Thanks

njncdmjt

It's looking like the controller is the culprit here. I did some more testing and am hoping someone here can confirm my diagnosis based on findings.

These are readings from the controller terminals while condition is occurring:

Top three small wire terminals from front of cart to back

Yellow: 0 - 5.75 v varying by pedal position. Theres a dead spot in there along the way but that hasn't been noticeable while driving.

Green: 9v starting when accelerator is pressed slightly

Red: 50v when solenoid clicks

With voltmeter positive lead hooked up to the blue cable at the controller and negative lead to b- there is 50v at rest.
When the accelerator is pressed the voltage is unchanged and there is no power at the wheels.
After pumping the accelerator several times, the cart will wake up and I'll see voltage drop on the meter indicating the controller is starting to complete the circuit.

Assuming all of the inputs to the controller are good I have to call it a bad controller.

So Assuming I got it right, I'll post another thread asking for advice on a controller motor upgrade combo. Trying not to spend too much though.

Many thanks

njncdmjt

Cart is fixed. I replaced the mcor and all is well.