Did you know the number one cause of early failures of lead-acid industrial batteries is sulfation? The build up of lead sulfate crystals eventually leads to loss of cranking power and longer changing times.
Battery plates regularly get sulfated. When batteries discharge, the lead active material on the plate reacts with the sulfate from the electrolyte and forms a lead sulfate residue on the plates. This reaction drains the battery of all lead active material and sulfate from the electrolyte remaining causing the battery to be fully discharged. After the battery is fully discharged like this, a recharge must commence as soon as possible. The recharge process consists of the lead sulfate residue converting back into the lead active material and the remaining sulfate is returned to the electrolytes.