Sulfation happens inside Lead–acid batteries when the electrolyte starts to break down. As the sulphuric acid (electrolyte) splits up, sulfur ions become free forming crystals. These sulfur ion crystals then stick to the lead plates of the battery, thus forming lead sulfate crystals.

What causes sulfation in a battery?

How does battery sulfation occur. Sulfation occurs when a battery is deprived of a full charge, it builds up and remains on battery plates. When too much sulfation occurs, it can impede the chemical to electrical conversion and greatly impact battery performance.

At what voltage does sulfation occur?

Any less than 12.6 volts means your battery is undercharged, possibly as a result of sulfation. It is also a possibility to conduct a visual sulfation diagnostic test on your battery's cells. This will require opening your battery, so it is advised to do this on a covered surface, in a well ventilated area.