Description & Operation: Battery: Sulfation
WARNING: This page is about a different car, the 2004 Suzuki Aerio, 2003 Suzuki Aerio, and 2002 Suzuki Aerio. However, it is still accessible from the selected car via links, so may be relevant.
If the battery is allowed to stand for a long period in discharged condition, the lead sulfate becomes converted into a hard, crystalline substance, which will not easily turn back to the active material again during the subsequent recharging. "Sulfation" means the result as well as the process of that reaction. Such a battery can be revived by very slow charging and may be restored to usable condition but its capacity is lower than before.