Testing procedures for dcs controlled machines

[MariusPerron]

Hello from Texas,

I am an electrical engineer helping my parents fix their 1995 EZGO Electric Medalist Fleet DCS Golf Cart. The cart motor does not come on in forward or reverse, even though the batteries are full 36 volts.
From Buggies Gone Wild, I downloaded the helpful PDF document titled, “TESTING PROCEDURES FOR DCS CONTROLLED MACHINES”. Everything was good until step 4 (see attached screenshot)
With my voltmeter on pin 5 of the controller, the reading is 0 volts. When we press the accelerator pedal, the reading goes to approx 4.5 volts, and the Solenoid does not click.

A couple of other facts – as I move the 10-pin connector that is on the controller, I see arching and sparks from the pins 9 and 10. I took the connector off and cleaned it – no change.

AND...! When I was about to come in the house, I put my hand on the motor... It was VERY HOT TO THE TOUCH!!!

AND – about a week ago, my grandfather ordered a new solenoid and put it in... perhaps he wired it wrong...

Any help would be appreciated.

Marius Perron

[MariusPerron]

Bump

[JohnnieB]

Originally Posted by MariusPerron

Hello from Texas,

1. I am an electrical engineer helping my parents fix their 1995 EZGO Electric Medalist Fleet DCS Golf Cart.

2. The cart motor does not come on in forward or reverse, even though the batteries are full 36 volts.

3. From Buggies Gone Wild, I downloaded the helpful PDF document titled, “TESTING PROCEDURES FOR DCS CONTROLLED MACHINES”. Everything was good until step 4 (see attached screenshot)

4. With my voltmeter on pin 5 of the controller, the reading is 0 volts. When we press the accelerator pedal, the reading goes to approx 4.5 volts, and the Solenoid does not click.

5. A couple of other facts – as I move the 10-pin connector that is on the controller, I see arching and sparks from the pins 9 and 10. I took the connector off and cleaned it – no change.

6. AND...! When I was about to come in the house, I put my hand on the motor... It was VERY HOT TO THE TOUCH!!!

7. AND – about a week ago, my grandfather ordered a new solenoid and put it in... perhaps he wired it wrong...

Any help would be appreciated.

Marius Perron

1. I suspect the electrical aspects of the EZGO electric carts were designed by Mechanical Engineers.

2. A 36V battery pack at 36V is only about 50% charged. Fully charged is 38.2V.

3. Attached is a service manual that ought to cover your cart. The F/R is different in earlier models, but everything else is the same. (Schematic for early DCS carts attached)

4. Ought to be full battery pack voltage (38.2V). Current path goes through 5 switches and 7 lengths of wire so there are many possible places for the voltage to be lost.

5. The sparks mean the Run/Tow switch was not in the Tow position when connecting or disconnecting anything electrical. If the controller wasn't bad, it may very well be now.

6. Might have some shorted MOSFETs in the controller, but without the solenoid contacts closing, the current path would be through the 250Ω resistor bridging the solenoid contacts.

7. check the cart's wiring against the schematic.

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If the controller is bad, do not replace it with a stock DCS controller.

DCS was EZGO's first foray into sepex motors and the controller is a flawed design (No undervolt protection and some other stuff) the was replaced by the PDS system in 2000.

Replace it with an Alltrax XCT controller.