1988 Ez-go killing batterys and stopping

[tdump]

OK,I charged the battery's some and as that was happening I checked out some stuff. I made sure there was no contact between any of the copper lugs on the throttle board. after about 3 or 4 hours charge I went for a drive sitting on a piece of plywood so i could reach in and feel wires and smell and see better than with the seat on it.
As I drove the only warmth I felt was near the rear resistor. Which with wide open throttle,going up a hill, I don't think there should be anything going thru that resistor
I was under the impression that once you went full throttle you were bypassing all that speed control stuff ,is that right?
I didn't ride it long and took it back in and checked to make sure the throttle brush was only touching 1 contact at wide open. it is only touching 1.

[tdump]

Ok,a overnight charge and a Simpson 260 hooked across the battery's. 39 volts after about a 7 hour lay over from the charger.
I then drove the cart up a few hills and back to the neighbors. He and his dog jumped on and off we went to his pond and all around his place. The meter held at 37 volts ,even going up a hill full throttle that is hard to walk up.
Ok, I then drove it home alone. 38 volts and when I got to the steepest hill around it did go down to 37.
But it finally showed it's butt. As soon as I got to the top of the hill I let off the go pedal and let it coast down the hill then turned left into my driveway. It was like stepping on a plumb. Not much happened and the needle went down to about 25 volts.As I went up my driveway it just kept going down till it got to 10 volts and would not move. It is back on charge . I mentioned what happened and the neighbor verified, that is how he has been left walking except he did not have a volt meter to see the change .

So why would it be a Sudden drop like this? looks like battery's would go down slowly? Is making a turn changing something in the rear axle and shifting the motor around and causing a internal short because of to much end play?

[teecro]

My suggestion is the next time you can duplicate this problem don't plug it into the charger. Let it sit for a couple of hours and check battery voltage and see if it will drive again. These USP batteries are cycled out and while they may indeed still have life in them they may be shorted across the bottom of the plates which makes them act like smaller batteries. But if after a cool down it acts normal again I'd look into the motor or controller etc getting hot....

[tdump]

I wish I had checked for heat this last time but I was more concerned about getting it coasting into a charger without having to push-pull the thing .
But ok,makes sense to see what the voltage is after a sit still.

I do know when it happened to the neighbor at his pond and we pulled it here the batterys did not come back enough for it to pull it's self in the 3 hours it sat at the pond. he was to the point of pushing it into the pond!

[teecro]

Originally Posted by tdump

I wish I had checked for heat this last time but I was more concerned about getting it coasting into a charger without having to push-pull the thing .
But ok,makes sense to see what the voltage is after a sit still.

I do know when it happened to the neighbor at his pond and we pulled it here the batterys did not come back enough for it to pull it's self in the 3 hours it sat at the pond. he was to the point of pushing it into the pond!

Sounds to me like the batteries have become "short"

[teecro]

I had a lawn mower battery that recently held great voltage but would absolutely not crank the mower or take any charge....

[Volt_Ampere]

Sounds like your batteries are way down on capacity. Time for new ones.

[tdump]

Yea, I am about to draw the conclusion that we got a dud set because there is just not much else it could be.

[radioman]

I would check each individual battery's voltage when it quits. It is unlikely they would all fail at one time. You don't have to disconnect them to measure each battery terminal voltage in series connected batteries. No series connected battery bank is stronger than the weakest one.

[tdump]

Well I am thinking battery's.
Here is the latest test results
I made sure they were charged as the automatic charger would do. I unplugged and plugged it back in twice today to make sure.
I load tested each battery with a 100 amp load test. 13 volts before clicking the button, about 11.9 as the button was held and the coil heated up. All 6 gave the same result.
I then took the cart up and down some long hills. All the time watching the Simpson 260 needle. it held between 37 and 38 volts . I decided to take it back to the neighbors. I made a hard right and hit a bump, the needle went down to 30 and by the time I got to his house it was down to about 15. It got to his charger and it is on now.
I load tested each battery. All but 1 went down to 6 volts under load, the other just about 7. So I am thinking battery's.
But why does a bump change things?
Loose connection>? Shucks I did tighten it all up Saturday.

So the neighbor has decided to do this. His melex works well. But has no bed on the back. He is thinking of swapping the battery's from 1 to the other. If the issue follows the battery's, it is a no brainer, if the issue stays with the cart, well we got some trouble shooting to do.

But he ask about a volt meter that could be mounted on the cart. I have wanted 1 for some of my carts but thought to expensive.
But I found this, and ordered 4 of them. 2 for his carts and 2 for a couple of mine. it will take a while to get them here but for the savings over some of the US venders selling the same meter, it is worth the wait.

http://www.ebay.com/itm/Golf-Cart-Di...3D171657977326