Undercharging occurs when the battery is not allowed to return to a full charge after it has been used.Easy enough, right? But if you do this continuously, or even just store the battery with a partial charge, it can cause sulfating. (Spoiler alert: sulfation is not good.) Sulfation is the formation of lead sulfate on the battery plates,. While you certainly don't want to keep your battery in an undercharged state, overcharging is just as bad.Continuous charging can: 1. cause. Because water is lost during the charging process, damage can occur if that water is not replenished. If the electrolyte level drops below the tops of the plates, the damage can be. The issues surrounding over and under charging as well as over and under watering can be a fine line to walk. It's really just about finding. Not only can your battery have too little water to function properly, but it can also have too much. Overwatering can cause the electrolytes to become diluted, which results in diminished battery performance levels. Pro tip: a normal.