Batteries Fully Drained + Overcharged = Self Accelerating & Smoke
 

Hi everyone, first time here, appreciate you guys in advance for any assistance. I know very little and sort of winged it through the first couple of issues but should probably stop and get some advice before I blow this thing and myself up!

Late 80's EZGO 36V purchased 1 month ago. Was running fine. A week ago I was driving it, again running fine power seemed fluid, then parked for maybe 3 hours. Key was off, very light rain throughout the day. When I got back on, it went maybe 6 inches and stopped. Seems as though the batteries were dead and thus the charger would not firee.

I purchased a battery tester and it reported they were all bad. Figured that to be BS so kept digging. I opened the batterys and found the water was very low so I topped all the chambers off short of about 3/4" from the top.

OK need to pause here and point out that, prior to adding water, I had been doing all kinds of stupid stuff trying to get power into these things. I tried using a 12V charger to charge 2 batteries in a series. Didn't seem to work. I hooked up a 1A charger and later a 3A charger (both for 6V) to individual batteries and to the circuit and they would not fire. So I used one of those jump starter devices, about the size of 2 IPhones stacked upon eachother, that is supposed to be able to jump a car 25+ times. When I used this, the 1A and 3A chargers would kick on. I let them run for over a day and when I tested the batteries it still indiciated 0% or BAD. Also, at one point, when I was jumping a battery using this device, it pulled almost 80% of the fully charged device power out of it within maybe 10 seconds.

My point is that I probably hooked these variety of options up in the wrong way. I got smoke twice. I know, I'm an idiot and that was dangerous but nothing blew up and eventually, it seems after adding water and then using the jumper, the golf cart charger kicked on. I let it charge overnight and the next morning (today) it drives with plenty of power.

Problem is..

It seems to accelerate on it's own. Key must be switched to ON. As soon as I flip it to Forward or Reverse, without touching the pedal, it goes.

Within 1 minute, there was smoke coming from under the seat. Even with it stopped it seemed to persist. Removing the key (possibly just turning the key to OFF, not sure) made it stop.

+ There is a metal coil that was red hot. Inside the little metal box thing between the battery pack.

Not sure what's wrong. Please don't forget that the batteries seem to die the very first time and go to zero even though I had been using it day-to-day. That could have been a shortage of water, or maybe something shorted out, and is resulting in these new symptoms as well?

Any ideas on where to start?

Re: Batteries Fully Drained + Overcharged = Self Accelerating & Smoke
 

See if the go pedal is returning all the way back to the first post on the wiper board. Check and see if any coils are broken or touching. See if the battery cables are broke at the coils or the battery post

Re: Batteries Fully Drained + Overcharged = Self Accelerating & Smoke
 

To start with, you either have a stuck solenoid or something is making it activate when it should not be activated.

Look in the EZGO "stickys" and find the wiring diagram that matches your cart. You will need it and that way others know what you have.

(Rib you type faster than me LOL)

Re: Batteries Fully Drained + Overcharged = Self Accelerating & Smoke
 

Thank you guys for your assistance. Sorry for the delay. Also, I'm learning a lot about this stuff by troubleshooting the areas you recommended - thank you. Quick response to your posts and then have updated symptoms, etc. that I think will give better insight into the issue.


The pedal appears to be going back to the first post on the wiper board. I'm only aware of one coil (the one about the size of a soda can) and it does not appear to be damaged. It has flared up 3 times now and resulted in smoke each time. The wiring was pretty rough when I got the cart, however I have - since these problems started occurring - cleaned up the terminal connections.


I've done a continuity check on the solenoid and during those checks it seems it is going on and off appropriately. I also hear the "click" when switched on. I haven't really been able to test this when the problem is (randomly) occurring as the smoke and phantom acceleration take priority.

As far as the wiring.. everything is mapped the same way as when I had the cart and it was operating fine for over a month.


Please give me feedback on the following suspicions along with anything you think I should do to prevent damage to myself or the cart. I really do appreciate your help.

Some things that have occurred since the last post..

1. I cleaned up the wiring. It has only flared the coil one time during the random acceleration events, whereas before it did it every time, although this was only done once.
2. Twice now there has been a big spark, possibly even a flame once, by the controller box. I think it might by arcing.
3. With the ignition turned on, the following can be observed..
Switch to Neutral - no activity
Switch to Forward - no activity
Switch to Reverse - no activity
Switch to Forward, tap go pedal - moves forward, random forward acceleration, random reverse acceleration
Switch to Reverse, tap go pedal - moves reverse, random reverse acceleration, random forward acceleration
4. I'm probably using it wrong, but when I hook up the battery pack to a volt meter tool, it reflects about 40 volts, then around 18, then around 5, then 0 - all in less than 2 seconds. It stays at zero until I stop contact with the POS or NEG and then reapply contact. Again, probably using it wrong, but when I check the volts, it's hitting 200+ for a moment and then drops to 0.

So what should I attack next? There seems to be a surplus of power getting pushed through it. There is a consistent big spark next to the controller box. The wiper board thing appears to be functioning OK but I feel like something to do with that is malfunctioning and pushing a bunch of energy.

Thanks in advance.

Re: Batteries Fully Drained + Overcharged = Self Accelerating & Smoke
 

Also, I'm trying to get better information on what type of cart this is. The serial number appears to be (and any observations are appreciated) 414505 but when I enter that at the shop dot txtsv dot com website it doesn't seem to respond.

Re: Batteries Fully Drained + Overcharged = Self Accelerating & Smoke
 

It is a EZGO Marathon. "89-'92, but possibly '87 or '88 or even '93. It is a resistor cart so it is not solid state and no speed controller.

The wiring diagram is here: http://www.buggiesgonewild.com/elect...rt-wiring.html Post #2 is the one I would use. I might have a better one. I'll see if I can find it.

I'm not a cart mechanic but I did own one of these for awhile. The first thing I would do is replace the battery in your volt meter. Those things give weird readings when the battery is weak.

The next thing is I would replace the wiper on the speed board. A common problem area and replacement part is cheap.

I think you have more than one problem. You need to determine the health of the battery pack. Difficult to troubleshoot a cart when the batteries are weak/shot.

Here's a picture of the speed board and foot switch wiper.

Re: Batteries Fully Drained + Overcharged = Self Accelerating & Smoke
 

The foot switch wiper is torn up in several spots where there was friction. Also, the wire coming from the solenoid to the wiper board - like it connects on the side opposite to the wiper contacts - also had exposed wiring.

Will attack both of these, and also check some type of spot that can supposedly fill with water under the pedal??, and follow up.

Thanks!

Re: Batteries Fully Drained + Overcharged = Self Accelerating & Smoke
 

srobertson88, are you saying that when in FORWARD or REVERSE the cart will randomly go forward or reverse?

Re: Batteries Fully Drained + Overcharged = Self Accelerating & Smoke
 

Just something else to consider once you get everything straightened out, is the condition and placement of some of your cables. I’m looking on my phone, but it looks like you’ve got some potentially funky connections on a couple. I see one of the battery cables that looks like the shrink is inside the lug?? Also, make sure the high amperage cable is always the first in the stack when you’ve got multiple wires on one post.

Looking forward to seeing you get it all straightened out.

Re: Batteries Fully Drained + Overcharged = Self Accelerating & Smoke
 

It only did the Forward AND Reverse one time. It rolled forward a little under 1' and then went into reverse slowly until I killed it.

Edit: I don't remember if I had placed it in Forward or Reverse at the time this occurred.