EZGO DCS problems

[scottyb]

Originally Posted by atr42flyer

Scotty,
I was hoping you would respond. When you got JB - you don't need me

It is a 1996 Ezgo TXT DCS, It didn't have a diode between the two small terminals on the old solenoid.

But I did buy a brand new recharge resistor https://diygolfcart.com/solenoid-res...CABEgJRrfD_BwE

The controller popped last night. So I need to send it back for repair. (again)

on a DCS cart is the smaller diode required? I did not see one on the wiring diagram. The Curtis control requires the 250Ω precharge resiostor and the 1 -3 amp arresting diode

I will try and upload a pic of the solenoid later

Originally Posted by mutant

put an alltrax in it...

Repaired controllers is the epitome of good money after bad

[mutant]

DCS controllers have a fatal flaw and to rebuild is kinda like...... well,you see-i had this dog and he would not come when i called him-so i went over and started beating him-but he was dead..........................................

[atr42flyer]

Originally Posted by mutant

DCS controllers have a fatal flaw and to rebuild is kinda like...... well,you see-i had this dog and he would not come when i called him-so i went over and started beating him-but he was dead..........................................

lol ok ok ok I get it, but still I want to know what the heck went wrong. Here are some pics of the solenoid. where did I goof up?

[atr42flyer]

So I think I may have figured out where I went wrong. I have the A2 wire from the motor going to the solenoid. I have looked at other pictures and it appears to go to the B+ terminal on the controller?
On the wire diagram I was using from this site shows it going to the solenoid, so thats my excuse for wiring that way but it kinda makes sense, that is the reason for the B+ wire from the controller to the solenoid got so hot and running at half speed.

Opinons?

[JohnnieB]

If the cable on the large solenoid terminal on the right side of the pictures is from the B+ terminal on the battery pack, the Diode/Resistor PCB assembly is installed correctly.

I cannot tell from the pictures, but if the small white wire with yellow stripe is connected the the left side small terminal that also has a red and a yellow wire on it, the control wiring is correct also.

Neither the DCS nor the PDS had a discreet diode between the small solenoid terminals as it came from the factory, but adding one is probable a good idea. I suspect a spike suppression diode was incorporated within the controller.

The Diode/Resistor PCB was unique to the DCS. The PDS only had a pre-charge resistor between the large terminals.

This is speculation, but I suspect the diodes on the DCS PCB were there to prevent the controller from being over-volted if the solenoid de-energized while regen braking was occurring. I'm not sure why regen diodes weren't used for PDS drives, perhaps they were incorporated inside the controller.
FWIW: Alltarax XCT controllers for DCS, PDS and TXT-48 all have regen diodes and spike suppression diodes, but no pre-charge resistors.

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I noticed the A2 cable is original and the cable lug doesn't look very good. That may be the heat source.

[atr42flyer]

Originally Posted by JohnnieB

If the cable on the large solenoid terminal on the right side of the pictures is from the B+ terminal on the battery pack, the Diode/Resistor PCB assembly is installed correctly.

I cannot tell from the pictures, but if the small white wire with yellow stripe is connected the the left side small terminal that also has a red and a yellow wire on it, the control wiring is correct also.

Neither the DCS nor the PDS had a discreet diode between the small solenoid terminals as it came from the factory, but adding one is probable a good idea. I suspect a spike suppression diode was incorporated within the controller.

The Diode/Resistor PCB was unique to the DCS. The PDS only had a pre-charge resistor between the large terminals.

This is speculation, but I suspect the diodes on the DCS PCB were there to prevent the controller from being over-volted if the solenoid de-energized while regen braking was occurring. I'm not sure why regen diodes weren't used for PDS drives, perhaps they were incorporated inside the controller.
FWIW: Alltarax XCT controllers for DCS, PDS and TXT-48 all have regen diodes and spike suppression diodes, but no pre-charge resistors.

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I noticed the A2 cable is original and the cable lug doesn't look very good. That may be the heat source.

in the Top pic, the cable labeled B+ got super hot, goes to left side (looking at pic) of the solenoid, also then connects left side of solenoid to the A2 wire on the motor.

[atr42flyer]

Originally Posted by JohnnieB

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I noticed the A2 cable is original and the cable lug doesn't look very good. That may be the heat source.

Ok I will get a new cable for that for sure.

[JohnnieB]

Originally Posted by atr42flyer

So I think I may have figured out where I went wrong. I have the A2 wire from the motor going to the solenoid. I have looked at other pictures and it appears to go to the B+ terminal on the controller?
On the wire diagram I was using from this site shows it going to the solenoid, so thats my excuse for wiring that way but it kinda makes sense, that is the reason for the B+ wire from the controller to the solenoid got so hot and running at half speed.

Opinons?

The short cable to B+ on the controller and the A2 cable were both on the solenoid's controller side large terminal as it came from the factory. I'm not sure why EZGO did it that way, perhaps it used less cable. Cursory inspection says the controller side large terminal and the B+ terminal on the controller are the same point electrically, but there are two circuits involved (Motor current and Battery current) and how much current flows in the short cable is different, depending on where the A2 Cables is connected.

When the duty cycle of the PWM output of the controller is anything other than 0% or 100%, the Motor current is greater than Battery current, so the most efficient way to connect those two cables is the stack them on the controller's B+ terminal. However, the way those two cable are connected is not the source of your heat problem.

[JohnnieB]

Originally Posted by atr42flyer

Ok I will get a new cable for that for sure.

There are 10 high current cables in a DCS drive and all ten ought to be replaced.

The A1 and B- cables look original also.

[atr42flyer]

Originally Posted by JohnnieB

There are 10 high current cables in a DCS drive and all ten ought to be replaced.

The A1 and B- cables look original also.

yes I replaced 7 cables already and will purchase the other 3