Help with Speed Upgrade - 2015 EZ-GO TXT

[JohnnieB]

Does the solenoid click when pedal is pushed?

If it does, the problem is in the high current circuit. (heavy cables)
If it doesn't. the problem is in the control circuit. (thinner wires)

The black "wire" between the solenoid's large terminals is actually a resistor. For a 48V system it should be a 470Ω 10W resistor.
It is called the pre-charge resistor and its purpose is to keep the large filter capacitors inside the controller charged to near the battery pack voltage so the amount of arcing on solenoid's contacts is reduced as they bounce during closure.

Lead-acid batteries and battery packs are identified by the sum of the number of 2V cells they contain and a 48V pack contains twenty-four 2V cells. However, that is the name rather than the actual voltage. A fully charged 48V battery pack made up from Trojan brand batteries is 50.93V, as measured 12 hours after charger shuts off. The 53V you got is probably due to taking the voltage reading lees than 12 hours after charging stopped.

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What is the voltage on the yellow wire going to one of the solenoid's small posts?

[mlaw8]

No click from the solenoid. Voltage of yellow wire is 53v.

Did I do something wrong when reinstalling the controller that caused this?

What do I do now? I assume the resistor needs to be replaced, but how do I address the control circuit you mention?

Could I have damaged the solenoid or the controller itself?

Thanks

[JohnnieB]

If the cart ran for a while after you reinstalled the controller, you didn't do anything wrong.

The resistor isn't needed for the cart to run, so worry about it later.

The control circuit is all the switches and other inputs to the controller. For the most part, measuring the voltage on the various pins on the white 16 pin connector plugged into the controller is all that is needed. To measure the voltage, use a small tipped test lead and push into the backside of the connector.

With charger unplugged from cart, Run/Tow in Run, Key ON and F/R in F (Pedal NOT pressed), you should have 53V (or whatever battery pack voltage is at the time) on Pins 5, 8, 9, 10 and 12.

If you get 53V on all of those pins, press pedal and you should get 53V on Pin-6 and Pin-12 should drop to 0V.

[mlaw8]

With pedal not pressed only pins 5, 7, 8, 13, 15, and 16 have 53 volts and others seem to have 0.

[kgsc]

If yellow has pack voltage then pin 10 should be hot also. If not you may have a bad wire.

[JohnnieB]

Originally Posted by mlaw8

With pedal not pressed only pins 5, 7, 8, 13, 15, and 16 have 53 volts and others seem to have 0.

When Pin-8 has B+ (battery pack voltage) on it the controller is in Forward.
When Pin-16 has B+ on it the controller is in Reverse.
Those two conditions are not very likely to exist.

I suspect you are counting the pins wrong.
They are labeled on the schematic I attached.
Bottom row is 1-8 right to left (Pin-1 is bottom right)
Top row is 9-16 right to left.

[mlaw8]

I think I may be going crazy or maybe my meter isn't accurate (or both). I think I'm counting the pins correctly...bottom right pin 1 and top right pin 9.

I rechecked all twice and got very different results...now pin 1, 2, 4, 13, 15, 16 have battery voltage, but it seems like 13 and 15 have about 1 volt less than the others.

I also checked the yellow wire on the solenoid again and am getting 53v on that.

Is this at all making any sense?

Thanks again for your assistance and time!

[R.Boyd]

Did you all notice that red wire with the grey stripe? It looks like it has arced on the corner of that metal plate and charred. I would suspect that is the culprit.

[mlaw8]

Originally Posted by R.Boyd

Did you all notice that red wire with the grey stripe? It looks like it has arced on the corner of that metal plate and charred. I would suspect that is the culprit.

Can't be positive because as I was inspecting the reg and grey wire I burnt my finger on the resistor...it definitely got fried...but it didn't appear that the red/grey wire was damaged. I will look again though (with gloves).

Thanks

[kgsc]

Sounds like the solenoid might have died. Cart will attempt to go and if the solenoid isn’t working all the current tries to go through the resistor and it will get really hot.