battery discharge issue

[hookdaddy]

I have a 99 club car here at my home in Florida. While we were gone over the summer (about 5 1/2 months ) Before I left the batteries were all full and charged. The cables were corrosion free and tight.
When we returned yesterday I found 5 out of 6 batteries were dry and the cable ends all corroded! One of the battery ends appeared to be disformed as if it was melted. When I was removing the cables this end just fell apart.
The cart sat with the key out and the charger was NOT connected. This is how I left the car the previous 7 summers and never before did I come back to this.
Two winters ago I installed a new charging computer in the cart

Any ideas what happened? I had planned to replace the batteries anyway ( the were from December 2012 but I hate to risk damaging new batteries if something else is wrong.

Thanks in advance.

[NoleFan4Ever]

Unless it developed a dead ground somewhere and drew them all down, I have no idea. For them to be dry, there had to be an occurrence of the chemical reaction.....

[Fairtax4me]

Two possible causes:
1: One of them reached a state of sulfation that caused it to start moving current internally. It happens with older batteries. Once one starts to discharge it draws current from the others that are connected to it. they were all in a similar state of sulfation, and they all eventually boiled themselves dry.

2: Moisture and dust on the outside surface of the battery. It’s been a wet year for most of the east coast. Condensation on the surface of the batteries will cause current to pass from post to post. It only takes one battery to start the discharge process, the rest will follow because current moves from one battery to the next since they’re all connected. Eventually they just boil themselves dry.

[WalterM6]

I would suspect that someone was borrowing your cart. Any neighbors you can ask.

[scottyb]

Originally Posted by WalterM6

I would suspect that someone was borrowing your cart. Any neighbors you can ask.

My first thought