I have 2 group 31 batteries. I checked the water a couple weeks ago, and it was good. I run a 24v Terrova off them. They are fairly new. Had an issue yesterday. After a few hours, I noticed my TM was needing more power. I checked the battery meter, and no lights. As I use one of those batteries for cranking, I could not crank the motor. I got home and charged them. When I checked the water, this particular battery was low on water in every cell. Weird. I have a MK 2 bank charger, and it has been operating normally....always in maintain mode when batteries are charged. Anyone have any ideas of what’s going on? Tho other battery was fine. Also, if I top it off with water, any chance it is still good? Thanks.