PDS Troubleshooting couple of questions

[benrocks]

I have 6 EZGO TXT Carts, 3 are DCS and and 3 are PDS. Is there a trouble shooting test out there similar to the one posted for the DCS that indicates the correct voltage within each location?

I have a 2002 PDS I just rebuilt, and installed new batteries. All new cables on the batteries and I replaced the cable from positive post to the controller with a new heavier gauge cable. I have also upgraded the chip on the controller to a speed chip. I have inspected all existing cables on the motor and the controller to insure good connections and sound wiring. Each battery is giving me about 6.38 volts at rest and 37.8 volts at the controller. But the cart is really sluggish, very slow in revers. Not real peppy in forward either. This is even the case after the cart has been on charge for several hours. I have another 2002 TXT-PDS with similar voltage readings on the batteries but this cart takes off like a rocket in forward or reverse. So where should I start troubleshooting the suspected voltage drop?

[JohnnieB]

You can download the Service, the Parts and the Owner manuals for the PDS carts here: http://www.buggiesgonewild.com/elect...g-manuals.html
The three PDF file near the top.

The service manual has troubleshooting tree for a PDS drive in Section-F, but troubleshooting the high current circuit in a PDS is fairly easy. Just connect you DVM between the B- and A1 terminals on the controller and push the pedal just far enough for the solenoid to click and you should read full pack voltage. Then push pedal to floor (Rear tires off ground and cart on jackstands) and the voltage should decrease to 0V, or very near to it. (The controller drops about 0.1V for each 100A of current flow, but with the wheels spinning in the air, the motor won't be drawing many amps.)


If it passes that test, connect the DVM between the A1 and B+ terminals.

Now you should have 0V with pedal up and it should climb to full pack voltage (as measured between the battery pack's main positive and negative terminals at the time of test) with the pedal down.

The first test checks if the controller is opening up fully and the second test checks for excessive resistance in the high current cables, connections and contacts.

----------
With a 2002 PDS, you might have some 6Ga cables in the mix and they should all (10 of them) 4Ga or thicker.

The sluggishness might be a mechanical drag, so try pushing by hand and compare with the 2002 that runs well.

Could also be an ITS issue. Check the ITS voltages - Step-42 in troubleshooting tree.

[benrocks]

JohnnyB- I performed the two test you suggested. Also verified all 10 cables are 4 gauge and connections are acceptable. On the first test I got all kinds of crazy readings. When I depressed the pedal, the solenoid would click in and immediately click back out before I could even get any kind of an accurate reading. I placed the cart on charge for about 45 minutes. Checked the pack voltage which indicated 38 volts. Attempted the test again and got the same results. So I then took the entire control box and solenoid off of the other cart that runs good and installed on the problem cart. (both carts are same year model and PDS units) Got virtually the same results, however I was able to keep the solenoid engaged long enough to get some accurate readings on the meter.

The first test= with the positive wire connected to the A-1 terminal and the negative wire to the B- the meter read 3.9V before I depressed the pedal. After the pedal was depressed just enough for the solenoid to open i then got 0.7V. As I continued to depress the pedal the readings seem to go more negative and haywire.

The second test= (probably pointless since the first test didn't pass but I figured might be helpful in your diagnoses) With the positive wire connected to the B+ and the negative wire connected to the A1 I got 34V and it did not matter whether ti solenoid was open closed or the pedal was depressed or at rest.

At all times during these two test the wheels never moved and I could not get the back up alarm to sound while in reverse.

I'm thinking the problem is not necessarily in the controller.

[JohnnieB]

The voltage reading between B- and A1 (aka M-) before the solenoid clicks is due the the 250Ω resistor connected across the solenoid's large terminals. The purpose of the resistor is to keep the filter capacitors in the controller charged so the solenoid contacts don't arc as much when they close. Normally, the voltage between B- and A1 is a few volts less than full pack voltage until the solenoid contacts close and goes to full pack voltage when they do close.

You may be right about it not being the controller since one that worked in another cart was tried. Does the original controller work in the other cart?

If the controller is good, that leaves the misbehaving cart's wiring, battery pack and motor.

What does the battery pack voltage do as the solenoid clicks on and off?

----------------------
Find the inline connector between the cable coming out of the pedal box and cart wiring harness, disconnect it and try Test-1 with it disconnected.

--------
Somebody probably disconnected the beeper, it is attached to the passenger side glove box. Reconnect it and put controller in diagnostic mode. The controller just might give us an error code (via the beeper) that would be helpful.

[benrocks]

JohnnyB,

I installed the controller that came out of the troubled cart in the good cart and it seems to be functioning normally.

There is absolutely zero change in the pack voltage when the solenoid clicks on and off.

I searched mightily for an inline connector between the pedal box and the controller with no joy. The cable coming out of the pedal box consist of 4 wires encased in a grey shield and as far as I can tell runs continuously to the controller and connects in to j4 on the controller.

I was able to get the beeper working, however when I placed the cart in diagnostic mode I only got 3 beeps indicating the performance option. I then decided to see what the voltage was on the solenoid itself and this is when things got interesting. When placing the pos and neg leads on either side of the large post of the solenoid at rest I got 0.57 volts, when I depressed the pedal the voltage began to climb as high as 160 volts. While I had the pedal depressed the cart gave a diagnostic code of 4-1. I conducted this test 2 more times and got the same result. I came back about 15 minutes later and attempted the same test, this time no beeps and voltage readings with the pedal depressed seemed more normal (35-37). I again fiddled with the forward and reverse switch to get the beeper working and insured the cart was in diagnostic mode. Performed the same test one more time and again got crazy high voltage readings on the solenoid but this time no beeps. During all of these test the wheels never moved.

[JohnnieB]

Check the motor. You might have bad brushes.