PDS troubleshooting problem

[gmansc]

Hello all,

I am stumbling my way through a problem with my 36 volt 05 PDS and need some help. The cart only runs 11.5/12 mph with a Red Freedom chip. It has 2 year old batteries and I have 38.2 volts on a fully charged pack. It runs the same if I pull the Freedom chip or if it is installed. It used to run faster but we have been using it around the house and had no reason to question the speed. I took it back to the beach and on flat pavement noticed the drop. The cart is stock with just a flip rear seat and new springs. As a matter of fact this might have started around the time I installed the new seat and springs.

With the Freedom chip in I get 4 beeps showing it is in Freedom mode. Pull it out and cycle N/R to go into diagnostic mode and I get 1 beep only. It is not throwing any codes.

I pulled the speed sensor from the motor just to see what happened. It ran about 3 seconds then cut speed way down to about 3 mph. Popped it back in, cycled the tow/run switch and the same 11.5/12 mph. I have read about welded solenoids, speed sensor, and even the controller. I am somewhat near a repair shop but am wanting to learn more about these carts and how they work. Any words on wisdom?

Thanks in advance for any guidance.

[JohnnieB]

Even in the All Terrain mode (No mode plug installed), 12MPH is slow.

Are any of the 10 high current cables getting hot or very warm?
What is the battery pack voltage while cruising at top speed?
What is the voltage on J4 Pin-3 (black wire from pedal box) when pedal is pushed just far enough to make solenoid click and what is the voltage when pedal is on floor?

[gmansc]

38.3 Volts at rest. 35.8/36.2 at WOT 11.5 mph. No hot wires anywhere. J4 pin 3 1 volt at solenoid engage, 2.7 volts at WOT. Also Freedom plug out and did not notice any regen brake.

[JohnnieB]

All of those results look good.

Neither Freedom mode or All Terrain mode have regen braking, on the two hill modes do. See attached chart. (All four mode use regen braking when max speed for the mode is being exceeded and when the walkaway safety kicks in - Just doesn't have any when you lift your foot off pedal.)

The throttle is telling the controller to got to 100% duty cycle, so lets check and see if it is doing what it is being told to do. Connect your DVM between the M- (labeled A1 on 36V PDS controller) and B+ terminals on the controller. Should be the same as the battery pack voltage when WOT. (About "35.8/36.2" volts)

Also check for worn off insulation on F1 & F2 cables. Picture attached.

Does cart push easily by hand? (Run/Tow in Tow) It weighs half a ton and the motor is always connected to the drive train, so it'll take some effort to start it moving, but not much effort once it is moving on a smooth hard surface. Gummed up axle bearings and in differential will make it hard to move and knock down the top speed.

Could be motor issues as well.

[kgsc]

Flip the cart to tow, release the brake and see if it rolls easy. If not your spring install may be interfering with the brakes and slowing it down..

[gmansc]

Just to clarify. There is currently no plug in the slot. It should be running stock. I thought it had Regen braking when stock. 34.5 volts between A1 and B+ @ WOT. It did jump around some but could have been me trying to hold the leads on. Cart rolls freely in tow or run. It has no resistance at all. That seems strange. I remember it being hard to move by hand in run mode. Also, no broken or chaffed insulation on wires.

[JohnnieB]

Originally Posted by gmansc

Just to clarify. There is currently no plug in the slot. It should be running stock. I thought it had Regen braking when stock. 34.5 volts between A1 and B+ @ WOT. It did jump around some but could have been me trying to hold the leads on. Cart rolls freely in tow or run. It has no resistance at all. That seems strange. I remember it being hard to move by hand in run mode. Also, no broken or chaffed insulation on wires.

Irregardless on keyswitch and F/R status, when pushed or pulled or allowed to move unintentionally while the Run/Tow switch is in Run, the walkaway safety ought to kick in, applying max regen braking and sounding the beeper rapidly. Is it not doing that?

Use jumper wire with alligator clips to connect DVM test leads to terminals when you need more than two hand to do the task.
Something like: https://www.amazon.com/Double-Ended-...lligator+clips
Or: https://www.amazon.com/SE-TL10-10-Pi...lligator+clips
Or: https://www.amazon.com/TOTOT-Banana-...lligator+clips

[gmansc]

Beeper sounding but no resistance in run mode. I can push it easily. Before this issue I could tell regen braking was working when I would try to push it just a few feet. I would have move to tow.

[JohnnieB]

Everything seems to be pointing to motor issues.

Worn out brushes or carbon dust buildup creating an alternate path for current flow.

[gmansc]

Wow, I never thought it would be that serious. Can they be rebuilt? Do I pull it and have some kind of bench check done? I am guessing there is no way the speed sensor has any effect on any of these symptoms.

Thanks very much for all of your help.