DESULFATADOR.COM :: Desulfatador, Acondicionador y Reactivador Electrónico para Baterías de Plomo-Ácido Estacionarias o de Tracción
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Electronic Battery Desulfater, Conditioner and Reactivator
Benefits all types of Lead-Acid Battery (Flooded, AGM, GEL, Sealed, VRLA, Etc.) > Operating Principles

To fully understand the operating principles of our ELECTRONIC BATTERY DESULFATER, it becomes necessary to first understand the fundamental basics of a lead-acid battery. To make it easier to understand, we will keep the use of specialized formulas and terms to a minimum, although it is obviously impossible not to explain it fully without at least touch a bit on the scientific realm.

Gaston PlanteThe lead-acid batteries (or accumulators) are one of the oldest form of electrochemical energy storage. Since its development in 1851 by the French scientist Gaston Plante, their level of energy density and charge-discharge characteristics have been greatly improved over time, but nowadays their basic elements are still the same. They are available in a great range of capacities between 1 to 1000 Amp-hours (or even more), and are generally the lowest price to performance relationship alternative for most applications in comparison with any other type of battery. Hence their popularity and widespread use. There are basically three type of lead-acid batteries, the most common being the flooded type, there is also the AGM (Absorbed Glass Mat) type, and Gel. This last type is also known as sealed (or "maintenance free") battery, or VRLA (Valve Regulated Lead Acid).

Lead-acid batteries are extensively used for energy storage, backup power systems, industrial machinery, off-grid electrical systems, specialized electrical traction vehicles (golf carts, forklifts, wheelchairs, etc), and are used to start cars and trucks. Due to this lower relative cost and convenience, lead-acid batteries (and particularly VRLA types) are considered nowadays the battery type of choice, and have experienced considerable developments. Even so, lead-acid batteries still exhibit shortcomings like low energy density in relation to its weight and size, and a high degree of maintenance requirement to be able to function in a reliable way, plus its recharge process is quite slow.

The following equation represents both the process of charge and discharge of a lead-acid battery.

Battery Reaction Equation

In other words, this equation signifies that during the discharge cycle of the chemical reaction, both the material of the positive plate (lead dioxide, or PbO2) and lead (Pb) from the negative plate react with the sulfuric acid (H2SO4) to create lead sulfate (2PbSO4), plus water (H2O) as byproducts, and of course the energy that is set free during the discharge process of the battery. The lead sulfate that forms is mainly dissolved in the water that is generated, but a small portion has always a tendency to settle on the plates of the battery as small crystals. It should also be noted that the water production of this reaction also lowers the concentration of the sulfuric acid, which makes the electrolyte more prone to freezing when the battery is exposed to low temperatures while in a state of discharge.

During the charge cycle the electrochemical reaction is reversed: the lead sulfate and water are converted back to sulfuric acid (the small sulfate crystals dissolve back into the water), which at the same time frees the lead and lead dioxide which to return to its respective plates. This reaction is possible due to an external power source (charge) that is applied to the battery.

What was described above if the way the chemical reactions happen under normal conditions when a battery is new y its cell plates are "clean". There are several degenerative factors that play an important role as the battery is being used over time, and that have a strong influence over the gradual loss of capacity, or even the complete irreversible failure of the battery. These factors are: high temperature, mechanical vibration, wear and loss of plate material, and the sulfate buildup on them. Of these four factors, the process of sulfate buildup is practically speaking the only one that can be reversed, and where the effects of our electronic desulfater are a determining factor. According to the Battery Council International, about 8 out of each 10 batteries are damaged prematurely by sulfate buildup on the cell plates. This means that about 80% of those batteries where discarded because of loss a of capacity that could have been reversed, and the battery's useful service life extended with early use of our electronic desulfater. Even a good percentage of batteries that are in a state of somewhat advanced sulfate buildup would very likely been also able to be restored with our electronic desulfater

Battery sulfation is the biggest problem when lead-acid batteries with liquid electrolyte are being used. The process of discharge due to normal use forms a layer of lead sulfate over the plates. Normally this layer is composed of very small crystals that can easily dissolved and be reabsorbed into the electrolyte during the charge cycle. But if the energy balance cannot be reached for most of the time when the system is being used, the buildup of sulfate starts to increase in thickness. The charging current cannot remove it completely, and the active surface area of the plate starts to shrink, which greatly impacts the useful service life of the battery. This same process happens in batteries which are kept in storage for a long time without being fully charged on a regular basis. The possibility of sulfate buildup increases when the charge that is drained from the battery is not restored in a short time. Likewise, another well known contributing factor is when the electrolyte of the battery is allowed to reach higher than normal temperatures.

Note: the process of sulfate buildup that is mentioned here always refers to the effect on the cell plates that are immersed in the electrolyte (sulfuric acid), and should never be confused with the white or bluish/green oxide that sometimes forms on the battery posts as this happens when the acid gets in contact with them because of a leak of the battery case, or a faulty cell cap, etc. Its causes and solutions are very separate from plate sulfation, so this would never be part of the same topic that is explained here.

Next you can appreciate the three stages of a battery plate as time passes. It will be shown in its initial state when the battery is new, and subsequently the effect of advanced sulfate buildup. The last part will show the state of restoration of a battery after it has been conditioned with our electronic desulfater for a period of time.

Detalle Placa VirgenThe cell plates in a lead-acid battery are build and optimized in a way to create as much surface area as possible in order to maximize the contact with the surrounding electrolyte (sulfuric acid). As seen in the picture at left, under magnification these plates look very porous, as this will increase its surface area. When a battery is discharged, be it to supply current to a load, or by just sitting idle without any loads, small sulfate crystals form on the lead plates. This sulfate is a normal byproduct of the chemical reaction between the lead plates and the electrolyte. When the battery is recharged, most of the sulfate crystals will dissolve back into the electrolyte, but after some time, and after a number of charge and discharge cycles, the sulfate layer buildup tends to increase in size and density. This residue ends up choking the battery, makes it difficult to recharge it, and restricts the amount of current that the battery can supply to a level much lower than its original specifications. The main reason for this effect is because the sulfate crystals act as an insulator, and effectively will reduce and block off the useful area of the plate that otherwise would be exposed to the electrolyte. This accumulation of sulfate is specially prevalent when the battery frequently undergoes deep discharges, or is allowed to stay in a state bellow full charge.

Detalle Placa SulfatadaOn the picture at right one can see a plate that has almost completely been covered by sulfate crystals. This battery would be severely limited in the amount of current it can supply to a fraction of its original specification, and under ordinary circumstances would have to be replaced. The problem is that in a typical lead-acid battery, its plates want to be exercised. This means, they want to be charged completely in the least amount of time, even when they have only been partially discharged. On the other hand, if the charge is not immediately replaced, or they are left in a state of partial charge, the acid electrolyte will slowly but surely deposit a layer of sulfate that will "weaken" the battery due to the progressive reduction of useful surface area on the plates that can ultimately stay in contact with the electrolyte. This effect is derived from the fact that sulfate is a very effective insulator, and as the density of the layer is left unchecked to increase over weeks and months, the internal resistance of the battery will slowly increase accordingly. Finally, upon heavy current demands this internal resistance will reach a point where most of the voltage of the battery will be lost due to this internal resistance and very little will actually reach the point where it is needed, for example the starter motor of an engine.

Another factor that also contributes to the premature failure of the battery are conventional charging methods. Sulfate buildup inhibits the ability of the battery to accept a charge and then to release it when needed, because when charged a sulfated battery will heat up, speeding up loss of water, which is an essential part of the electrolyte mixture. The loss of the water causes the sulfate to be deposited on the plates as hard participles. This creates distortions of the cell, internal shorts, and eventuality complete mechanical failure. The charging problems are particularly apparent where batteries undergo frequent deep discharge cycles, as in battery banks used to supply electrical energy to systems that depend on them for a period of time before the charge can be replenished. Many chargers have limitations due to its fixed charging logarithms that do not take into account the sulfation factor. Even some of the smart multi-step chargers work in a way that the batteries are worn out prematurely due to sulfate accumulation during the charge process.

Detalle Placa RecuperadaIn this last picture to the left it can observed that the surface of a battery plate that has remained connected to our electronic desulfater for an extended period of time, ever since it was determined that it suffered degeneration of its capacity due to sulfate buildup. One can appreciate that the sulfate crystals have substantially been eliminated, and in turn restore the capacity of the battery because most of the useful surface area has been cleaned, and is once again available to generate electricity. Additionally, early adoption of an electronic desulfater has made it possible to stop accumulation of new sulfate deposits. It has been proven that given enough time, our electronic battery desulfater will restore the capacity even in batteries with heavy sulfate buildup, often restoring them to almost full capacity. In cases where the desulfater is connected early in the battery life cycle, it will stay in optimal condition year after year because it will constantly be conditioned. This way other factors like cell distortion, internal shorts, are also minimized.


Pulsed conditioners like our electronic battery desulfater have a long history in the maintenance of batteries, but its contributions have only recently been studied and understood. The main benefit comes from the mechanical resonant energy that each pulse gives the plate. The pulses slowly but surely manages to weaken and loosen the sulfate crystals, and by doing so, restores the working surface of the plate. This increase of surface area allows in term that the battery will increase its capacity, and makes it easier for it to accept a charge. The other benefit of the pulses pertains to the state of charge and overall health of the battery. It is well known for a long time that a constant charging current hurts the battery because it produces heat in its cells. On the other hand the pulses impart a very short but intense charging current, so the cells are able to use the electrolyte that is in contact with the cells to accumulate a portion of that imparted pulsed energy. This contributes to recharge the battery without creating damaging heat in its cells.

Even with all the advantages of electronic desulfating, in certain cases there are batteries that present an advanced state of failure that is beyong restoration and even by connecting our desulfater for extended periods will only yield marginal results. In our own experience the opportunities to restore the capacity of a given battery are maximized if the desulfating treatment is started as soon as the first symptoms of diminished capacitya appear, for example when a starter begins to have trouble turning over the engine. The chances of saving a battery are very limited if it gets to a point where it is barely able to engage the starter.

For more information, you can also visit our FAQ section.


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