Late 90s 36v TXT solenoid gets hot, clicks when parked

[Reel Fine]

Hi all. Brand new to the forum and looking for some guidance with an issue. I've had my late 90s 36v TXT for a few years now (can't seem to pinpoint exact model year). I've had issues with it on and off over the years, but when it's running, it runs SWEET.

A little history on me and this cart for reference: I'm not very knowledgeable at all when it comes to golf carts, but I'm often a DIY guy in other aspects of life. Since I never wanted to mess anything up on the cart, I usually take the cart to the local shop, but it doesn't seem that they actually fixed my last issue from November 2019. Got out of the driveway and within a couple hundred yards, I smelled burning plastic. Stopped and opened the seat to see the box where the controller sits was smoking. The shop changed a couple things around and told me that the previous owner had some things wired weirdly (previous owner also disconnected the tow/run switch for some reason). The shop said they fixed the issue with whatever was smoking, and it seemed to be running fine for a while. I also got new Trojan batteries while it was in the shop for this issue. Then a couple weeks later, I smelled burnt plastic again. This time, the positive terminal on the rear-left battery got so hot that it melted the plastic on the battery (see attachment 1). The shop said it was a faulty battery and replaced it with a new battery. After riding for a while, that same cable on the new battery would get pretty warm and "wiggly" while the rest remained cool and rigid, but the shop said that this was OK. Everything seemed to be running fine at this point, excluding that warm wire.

Now on to my NEW issue, which I am thinking is related to at least some of my previous problems. Yesterday, after riding for a short while, we stopped to talk to a neighbor. With the key still set to "on," something under the seat started clicking a little bit while parked. I turned the cart off, and the clicking stopped. Then after driving around for ~20 more minutes, we headed home. While pulling into the garage, we noticed a burnt plastic smell. The box where the controller sits was smoking again, and the same wire connecting the all-the-way-left batteries (opposite the controller) was hot and wiggly again. Opened up the box, and two wires that were touching what I believe to be the solenoid (round silver piece in Attachment 2) were melted, and the solenoid was very hot. I got a fan on it for a while and cooled it as quickly as I could. Taped up the little melted spots on the wires and charged it again. This morning, I took it on a 1 minute ride just to make sure it would still run, and it seemed to be working fine.

I've done a bunch of searching on this forum and can't seem to find what exactly is going on. Attachment 3 is the sticker on the controller, and Attachment 4 is the sticker on what I believe to be the solenoid.

So I guess these are the questions I have:
- What causes this solenoid to get so hot and how easy is it to fix?
- What causes the all-the-way-left wire connecting batteries to get hot and wiggly? Is it related?
- What causes the clicking when parked with key on, and is it related?

This cart is great when it works, but it always seems to have some sort of issue. Should I just get rid of this thing and get one in better condition?

Thank you in advance for all your help.

-Mike

[JohnnieB]

You have a DCS drive, which was EZGO's first attempt at a sepex (SEParately EXcited) and lacking under voltage protection the Curtis 1206SX controller was a high failure item.

Since the Run/Tow switch has to be placed in the tow position whenever the electrical system is worked on or when the cart is towed, it being bypass by the previous owner was a very bad idea.

The batteries are connected in series, so the same amps flow through all the cables and terminal, so whatever in melting the post on a specific battery is related to the melted terminal and the cable attached to it. The cable in the picture doesn't appear to be burnt, so it is the battery terminal and the most common reason for a terminal overheating is that the nut on the stud was over-tightened. The stud is simply a hex head bolt embedded in the lead battery terminal and if too much torque is applied, the head will turn in the soft metal, losing good electrical contact and causing heat due to far higher current density in the area still making contact. Torque spec is 95 - 105 INCH/lb or 7.9 - 8.7 ft/lb, which are amounts very easy to exceed.

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If you are satisfied with the way the cart performs when it works, install an Alltrax XCT48300-DCS (or larger) controller and a 200A continuous (or larger) solenoid and 4ga (or thicker) cables throughout (all 10 of them), and be sure too have Run/Tow switch installed.

[Reel Fine]

JohnnieB, thank you for the info! Let me make sure I have all this right:

- I need to install the run/tow switch - no prob

- Since only one cable is hot, it's related to one of the two batteries that it is connected to - likely damaged during overtightening.
- Assuming that I'll need to replace the busted battery, is it possible to tell which one is messed up? Since only the one melted battery was replaced, and it's the same cable location (shop replaced the cable with the melted battery), could it be the other battery attached to that same cable?

- I do like how the cart used to run, so I think I'll get an Alltrax XCT48300-DCS (or larger) controller and a 200A continuous (or larger). Does going larger on either of these components equate to an increase in performance at all, or just increased protection. This cart is pretty fast, and I'm wondering if installing these new components will affect speed at all. I like it fast.

- I'd assume that all the cables that the shop installed would be 4 gauge or thicker, but is there a way to check? The one that heats up is a different cable, so I'm wondering if I should just replace that one

- Would making all the above changes fix the clicking issue while parked? I think I read somewhere that it could be a bad pedal switch?

[JohnnieB]

Originally Posted by Reel Fine

JohnnieB, thank you for the info! Let me make sure I have all this right:

1. - I need to install the run/tow switch - no prob

2. - Since only one cable is hot, it's related to one of the two batteries that it is connected to - likely damaged during overtightening.
- Assuming that I'll need to replace the busted battery, is it possible to tell which one is messed up? Since only the one melted battery was replaced, and it's the same cable location (shop replaced the cable with the melted battery), could it be the other battery attached to that same cable?

3. - I do like how the cart used to run, so I think I'll get an Alltrax XCT48300-DCS (or larger) controller and a 200A continuous (or larger). Does going larger on either of these components equate to an increase in performance at all, or just increased protection. This cart is pretty fast, and I'm wondering if installing these new components will affect speed at all. I like it fast.

4. - I'd assume that all the cables that the shop installed would be 4 gauge or thicker, but is there a way to check? The one that heats up is a different cable, so I'm wondering if I should just replace that one

5. - Would making all the above changes fix the clicking issue while parked? I think I read somewhere that it could be a bad pedal switch?

1.

2. There is a single electrical path through the six batteries and seven cables that connect the batteries together and B- to the controller and B+ to the solenoid. The same number of amps flow simultaneously through all parts of that single path, so if a battery terminal melts or a cable gets hot, the problem is isolated to that location alone. In other words, the melted battery terminal was cause by something amiss with the battery terminal, the ring terminal's connection to the cable or the ring terminal/battery terminal interface (Connection). Since the original cable with its ring terminal was replaced when the first battery with a melted terminal was replaced, the suspect list has been narrowed down to the battery terminal that has now been melted. The most common cause of a stud type battery terminal failure is over-tightening.

3. The top speed typically increases when the stock controller is replaced with any amp size XCT-DCS controller. Mostly due to better field mapping. The 300A version is more or less the same as stock for low end torque while the 400A and 500A version up the low end torque. Stock speed was in the 12 to 14 MPH range and should be closer to 20MPH with the XCT controller.
(If your cart is faster than stock, it might have taller than the 18" tall stock height tires on it.) For a solenoid, it should be at least 200A continuous and 600A or more peak.

4. The gauge is often printed on the cable insulation. Other than that, it is pretty hard to tell unless you have a piece of cable that is know to be a specific gauge for comparison. The cable on the melted terminal seen in the picture appears to be okay.

5. In a DCS drive, the controller energizes the solenoid. The pedal switch only tells the controller the operator wants the solenoid to be energized. So there are two possibilities, the controller is energizing the solenoid when it should be, or the pedal switch is telling the controller to do it when it shouldn't be. The pedal switch uses the N.O. (Normally Open) contacts tell the controller to energize the solenoid and the most likely failure is not working rather than working when it shouldn't, so the more likely problem is a defective controller.

BTW: turning off the key or shifting the F/R selector to Neutral will stop the solenoid from clicking.

Here is where I get most of my cart stuff: https://www.cartsunlimited.net/alltrax-xct-sepex--.html

[Reel Fine]

Just wanted to provide an update here. Many thanks to Johnnie B for all the guidance. After taking a ton of stuff apart, here are ALL the issues that I found with the cart. I can't tell what was done by the previous owner and what was done by the local cart shop, but I'll be doing everything myself moving forward.

Problems:
- 6ga cables all around
- Bad controller
- Bad solenoid
- TONS of melted wiring, random unnecessary splices/connectors, fraying connections to terminals
- Cables running to the motor were being pinched between the frame and leaf spring. One cable was like 75% cut through and exposed
- Bad run/tow switch (this caused all kinds of difficult-to-solve downstream issues, even after install of new equipment)
- White wire in charger receptacle was carelessly put back into housing and was being crimped

Solutions:
- New Alltrax XCT400 controller
- New SW180 200a solenoid
- New 2ga cables all around
- New run/tow switch (will install once delivered)
- Cleaned up all the wiring and replaced a lot of it
- Rerouted cabling to motor to stay out of pinch zone

[JohnnieB]

Wow!

Looks like your cart had more than its fair share of shoddy maintenance from previous owners and cart shops. I suspect she is going to live a long and health life now that she has a caring owner.