Final note. new cheap
wet deep cycle batteries have been installed.
I did play with the 'dead' batteries for a bit and put in a constant current charge into the old batteries for 3 days. Varying it from 1 amp to 3 amps. One battery did begin responding. I gave up when it would run my car head
lamps for at least an hour, but could not be charged enough to turn the car's starter. Apparently dead is dead, even if the batteries aren't abused. Sulfation sucks.
One note, after reading what our forum experts had to say about solar charge controllers, I revisited my decision to buy the one I bought 4 years ago. What I thought I bought was a fancy new digital controller for complete battery maintenance
. However, what I actually came home with turns out to be one of the infamous 'shunt' controllers. Apparently these just are not up to the task. I'm looking at replacing it with one of the Genasun GV-10-Pb controllers as folks here seem to think highly of them.