Looking at the other recent battery thread there is apparently a lot of knowledge on the subject here- way more than I have, so.....
I have about 20 LARGE two volt cells that I salvaged a few years ago. they are about 6" X 3" X 18" - when i first got them they were charged and seemed to have lots of power. Since then I did everything wrong- they've been left discharged over several winters, laid on their side from time to time, etc.
I looked them up online and they were designed to work for 20 years, i think they were installed in a railroad switch.
Right now a group six together just makes my charger freak out.
Anything worth trying? replacing the electrolyte? Charging each one separately?