Battery desulphation procedure: 
 

Desulfation is the process of reversing the process of sulfation that occurs to a lead-acid battery over time. Desulphation restores, at least partially, the ability of the battery to hold a charge over the life of the battery originally caused by sulfation). Sulfation is the formation of large non-conductive crystals of lead(II) sulfate (PbSO4) on the battery plates. Eventually so much of the battery plate area is unable to supply current that the battery capacity is greatly reduced. Desulphation is an attempt to reverse sulfation. Desulphation is achieved by high current pulses produced between the terminals of the battery. This technique, also called pulse conditioning, breaks down the sulfate crystals that are formed on the battery plates. Sulfation is a natural process that occurs in all lead acid batteries, but can occur significantly faster if placed in the wrong combination of temperature, poor charging technique, protracted battery disuse, etc.

Our example illustrates the way a battery bank behaves during a 4 years time period with a mark up of 480 recharging cycles. It is obvious that a massive build up occurs after 2 years or respective 240 recharging cycles. At that time it is more as necessary to employ an electronic pulse modulated desulphator in order to avoid the build up of bad cells and lost in battery capacity.