EZGO 36 volt controller wiring issue

[JohnnieB]

Okay, if the cart is wired correctly, would you please explain how you managed to measure 38V on all 4 of the big terminals of a Curtis 1204 controller.

I do not have your cart in front of me, so I must use you as my eyes and hands to troubleshoot it.

If the information I receive is not accurate, the advice I give is worthless.

[scottyb]

Is it possible that you have reversed the pot leads? disconnect both leads (4terminals) and recheck the pot out put, 0-5k will be at one pair only, make sure this is the pair going to controller pins 2+3. For test purposes tape the other two up so they can not touch each other and are out of the way for now. Leave them disconnected for the rest of the tests.

As far as the resistor betting blazing hot goes, this indicates that the Control is trying to draw pack amperage thru the resistor and not the solenoid, usually because the solenoid is not activated or it has failed. Remove the resistor and continue testing the solenoid.

[carp1595]

Just had an issue that might be your problem. My cart was stock so I started an upgrade. 2 ga wire HD solinoid and 400 amp controller. I put everything back like it was including the diod and resistor. Diod smoked and took out my ITS spead control micro switch. Took out the diod replaced the switch and everything seems to work. The wiring diagram shows the diod on non PDS but gone on PDS. My cart is non PDS. I don't know what the diod does but maybe it isnot needed with newer controllers. Happy I didn't smoke the solinoid or controller. Anyone know why that diod is in there?

[dannyferris]

JohnnieB Thank you for all the help. After another controller transplant the patient is up and running.

[JohnnieB]

Originally Posted by dannyferris

JohnnieB Thank you for all the help. After another controller transplant the patient is up and running.

[JohnnieB]

Originally Posted by carp1595

...........Anyone know why that diod is in there?

The diode across the solenoid coil protects the throttle microswitch contacts from arc damage.

When the solenoid coil (or any coil) de-energizes, the magnetic field that existed while it was energized, collapses rapidly and creates a huge electrical spike that is in the opposite polarity to the current that had created the magnetic field. Opening the throttle microswitch is what typically de-energizes the solenoid coil and electricity moves faster than the switch contacts can move mechanically, so the spike jumps across the air gap if they are still too close together when it occurs.

The diode is connect so it does not conduct when the voltage that energizes the solenoid coil is applied, but conducts when the spike occurs in the opposite direction, shorting the spike back into the coil, where it dissipates.

PDS controllers supply both B+ and B- to the solenoid coil and probably have internal spike protection of some kind or another and don't have the external diode, but installing one doesn't hurt.

DCS controllers use a hybrid solenoid activation circuit with B+ supplied by the throttle microswitch and B- supplied by the controller. I'm not sure why they put a diode across the contact terminals instead of the coil terminals, but I don't think adding one across the coil terminals would hurt.