1989 Club Car charging issue

[Teresa56]

The golf cart used to work perfectly until it was left plugged in to charge too long. Since then brand new batteries do not last beyond the first 200 ft of use. I have replaced the 3 AGMs 2x and bought a new charger, so that is not the problem and it is beyond my knowledge or capabilities.

I am elderly with terminal issues and use the golf cart for getting around quite often (not a golfer). Having it done has greatly hurt my life actually. I cannot find a service shop that works on these that are that old. I can follow instructions though and would like to troubleshoot but need lots of guidance. Thank you so much

[meimk]

Do I understand correctly that you are running 3 x 12 volt AGM batteries to provide your 36 volts? Not the best combination, but I gather they previously gave you significantly more run time than you are experiencing now. Do you have, or have access to, a hand held volt meter? A starting point would be to see what voltage the batteries have: End to end as a pack, and individually. For best accuracy the standard is to run your charger a full cycle till it shuts itself off. Let the cart sit disconnected from the charger for about 12 hours to let the batteries settle. Then measure the whole pack voltage (end + terminal to end - terminal). Then measure each battery individually - no need to disconnect any wires, just + to - of each battery. That will give us a starting point to help determine what's going on.
You say this all began when it was "left plugged in to charge too long"? Was your charger at that time old enough to have a manual timer? Most all newer chargers are "automatic" in that they turn themselves off once the battery pack reaches a pre-determined voltage.