Would anyone know the basic charging rates of an automatic charger? I'm going to monitor the charging rate on an 80% discharged battery (which is brand new) & don't know what would be considered in the 'normal' range.

Customer was using a faulty battery & was short charging it all day long for about 3 months before the decision was made to purchase a new battery. Old battery never got hot or smelled while charging- no matter how long on charge- new battery gets warm to the touch & smells of rotten eggs. Can't get a straight answer on water usage so I want to monitor it myself.- Not sure of specs- It's a 48V unit- Thanks