[Richard and Rhonda]

Jennifer,

Here is the first thing I would really look into. Twice you have posted that the batteries are fully charged, and the reading is 12.8. In my book, that ain't fully charged. You should be reading about 13 to 13.2 on fully charged.

I would try to analyze why. I can think of two reasons. One, the charger is not functioning properly. Check the output voltage of the charge. Two, you have a bad cell in one of the batteries. That would keep the whole bank from fully charging, and the whole bank would drop like a rock when you put a load on it. As others have said, check each cell with a hydrometer. Best way to do this is charge, take off charge, isolate each battery by removing the leads, and 24 hours later check each cell with a hydometer.

Checking with a hydrometer right after you take off the charger, and while all the bank is interconnected is not going to give you an accurate answer.

What I am describing is really not that much work.

Let us know what you find.