Hello friends,

I like to bring to your notice the main reason for Lead acid battery ( 12v battery used in UPS,Inverter,Cars,starting glow engine - plane and cars ) failure - SULFATION

What the hell is sulfation ?

During use, small sulfate crystals form, but these are normal and are not harmful. During prolonged charge deprivation, however, the amorphous lead sulfate converts to a stable crystalline that deposits on the negative plates. This leads to the development of large crystals, which reduce the battery's active material that is responsible for high capacity and low resistance. Sulfation also lowers charge acceptance. Sulfation charging will take longer because of elevated internal resistance.

There are two types of sulfation: reversible (or soft sulfation), and permanent (or hard sulfation). If a battery is serviced early, reversible sulfation can often be corrected by applying an overcharge to a fully charged battery in the form of a regulated current of about 200mA.

How does it occur?

Sulfation occurs when a lead acid battery is deprived of a full charge. This is common with starter batteries in cars driven in the city with load-hungry accessories. A motor in idle or at low speed cannot charge the battery sufficiently.

Sulfation occurs in all lead–acid batteries during normal operation. It impedes recharging; sulfate deposits ultimately expand, cracking the plates and destroying the battery. Eventually so much of the battery plate area is unable to supply current that the battery capacity is greatly reduced. In addition, the sulfate portion (of the lead sulfate) is not returned to the electrolyte as sulfuric acid. The large crystals physically block the electrolyte from entering the pores of the plates. Sulfation can be avoided if the battery is fully recharged immediately after a discharge cycle. A white coating on the plates may be visible (in batteries with clear cases, or after dismantling the battery). Batteries that are sulfated show a high internal resistance and can deliver only a small fraction of normal discharge current.
Sulfation also affects the charging cycle, resulting in longer charging times, less efficient and incomplete charging, and higher battery temperatures.

Batteries which have sat unused for long periods of time can be prime candidates for desulfation. A long period of self-discharge allows the sulfate crystals to form and become very large. Some typical cases where lead acid batteries are not used frequently enough are planes, boats (esp sail boats), old cars, and home power systems with battery banks that are under utilized.

How do I stop it?

Desulfation is the process of reversing the sulfation of a lead-acid battery. Desulfation 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.Short high current pulses tend to work best. Electronic circuits are used to regulate the pulses of different widths and frequency of high current pulses. These can also be used to automate the process since it takes a long period of time to desulfate a battery fully.

Desulfation

You can desulfate it by using chemicals or an electronic device.
To desulfate a battery using chemical look at http://www.ehow.com/how_10076192_desulfate-battery-epsom-salts.html
One can buy a commercial Battery desulfator or make your own...

Guys , anybody interested in battery desulfators ??

I am planning to make and sell Electronic battery desulfators - anybody interested??

Am extremely interested since i deal a lot with solar stuff and battery replacement seems like the biggest cost involved. If you are intending to manufacture a reliable device and let me know the approximate price, i can buy them as well as recommend them to friends facing similar problem.