24-volt system...1 battery got low water, but refilled with distilled water....will take a charge but won't hold it...especially as soon as you put load on it...almost immediately using TM on 24-v, guage reading on the 1-batter is 0...but TM still works on 24-v and continues to work.....anyway, is battery just shot? can I do anything? I charge on 6-amps tops on that battery and it's full of water....batteries are Everstart from Wally world and this is 2nd summer using.