Lead-Acid Battery Sulfation and Its Cure

     The chemistry of a lead-acid battery involves plates of lead (Pb) and lead oxide (PbO2) immersed in an electrolyte solution of sulfuric acid (H2SO4) and water (H2O). When an external connection is made between the lead and lead dioxide plates, electrons and ions are exchanged between all three chemicals. The lead and lead dioxide convert into lead sulfate (PbSO4) while the sulfuric acid converts into water.

     Lead sulfate is formed in greater quantities the deeper a battery is discharged. This soft, spongy material is easily converted back into lead and lead dioxide during the battery's recharge (only when the recharge occurs soon after discharge). If a battery is slightly discharged for a period as short as 70 hours, the this soft material (sulfation) will reform into a very stable covalent bond, "locking away" active material and preventing it from reforming into lead or lead dioxide. Each time this occurs, a battery's capacity is reduced, eventually rendering it useless.

     Not only does sulfation limit battery life by "locking away" available capacity, but these formations can grow so large as to actually cause structural damage, often resulting in an electrical short. As sulfate crystals consume capacity, the depth of battery discharge will become greater given a constant load. The depth of discharge is the percentage of total battery capacity drawn prior to recharging. The greater this percentage, the shorter the battery life.

     There are 5 different energy bonding states or energy levels for the sulfate ion. Over time, there is a transition from a less stable ionic bond to a very stable covalent bond. In its lowest energy or covalent bond state, sulfur forms a circular molecule consisting of eight atoms. There molecules stack up like shingles to cover the surface with a coating of circular molecules. There molecules are very resistive. The effect is like painting the battery plate with a resistive coating. The circular eight atom pattern is indicative of a stable bonding arrangement which will resist efforts to break. The useful life of lead-acid batteries is dictated by our ability to break up these deposits.

     Early attempts to convert sulfation began with equalization or "over charging". This process was successful at removing most of the deposits, but at a very high cost to the battery life span due to the erosion of the positive plate grid structure. The process, being highly exothermic, results in heat generation, plate warpage and mechanical stress on cell components. There are numerous examples of battery cells exploding as a result of equalization. Later a safer electronic charging process known as PWM or pulse width modulation was developed. This improved technique is still unable to remove the oldest and most stable sulfate deposits from the plates.

     To break these sulfate bonds, one must raise the energy level of the atoms to a point where the electrons in the outer valence band are excited to the next higher band, leaving the atoms unbonded in respect to one another. Each of the indentified energy states has a totally unique frequency that must be swept through. This is necessary to transfer the required unit of energy to this bond which enables the excited molecule to move to a higher state. This process is repeated until the bond reaches the upper most or highest excited state. Then, and only then, can it be converted to a free ion in the electrolyte. It is only by this series of steps that the sulfate, in its more stable covalent bond, can be converted back into the least stable lead sulfate molecule that can be removed off the battery plate into the free ion state through charging.

     This patended IES Sweeping Pulse Technology incorporated within Desulfator Battery Revitalizing Systems is the best solution for the elimination of lead sulfate deposits with no harmful effects to the battery. The charging frequency from these units will shift from 10 to 100 kilohertz. This sweeping action is required to break down all of the various bonding states, solving your sulfation problems.