Over time, different units within the forklift may produce slightly different power capacities. When this happens, the user cannot fully charge the battery; one battery can be fully charged while the other battery can only be charged halfway. Balanced charging prevents this inefficiency. In essence, balanced charging is a purposeful overcharging. A typical charging cycle lasts about eight hours, while a balanced charging takes about three hours. The charger continues to provide lower power during the last few hours.
This approach also prevents delamination, a potentially destructive condition under which the acid and water in the cell separate. In the final stage of balanced charging, the forklift battery releases hydrogen and oxygen. These evolved gases form bubbles that provide agitation to the electrolyte to prevent delamination.
Note that equalizing the charge requires a longer cooling time than a typical charge cycle. Since most battery manufacturers recommend equalizing charging weekly, many operations perform this task on weekends, providing enough time for charging and cooling before the next shift.