What is the effect of sulfation on a lead-acid battery and how can it be reversed?

Sulfation in a lead-acid battery is the formation of lead sulfate crystals on the battery's lead plates, which reduces the battery's capacity and ability to deliver power. Lead-acid batteries generate electricity through a chemical reaction between lead, lead dioxide, and sulfuric acid. During normal operation (discharge), lead sulfate forms. When the battery is recharged, this lead sulfate is converted back into lead and lead dioxide. However, if a battery remains in a discharged state for an extended period, or is repeatedly undercharged, the lead sulfate crystals become larger and harder, forming a permanent coating on the plates. This hardened lead sulfate is much more difficult to convert back into lead and lead dioxide during charging. As a result, the battery's active material is reduced, decreasing its capacity and ability to deliver current. Sulfation can manifest as reduced battery voltage, decreased cranking power, and a shorter lifespan. In some cases, sulfation can be reversed using a process called equalization charging or desulfation. This involves applying a higher-than-normal voltage to the battery for an extended period. The higher voltage helps to break down the hardened lead sulfate crystals, converting them back into active material. Specialized desulfation chargers use pulsed charging techniques to further enhance this process. However, desulfation is not always successful, especially if the sulfation is severe or has been present for a long time. Prevention is key. Keeping the battery fully charged and avoiding deep discharges will minimize sulfation and prolong battery life. For example, if a tractor battery is left discharged over the winter, sulfation will likely occur, reducing its ability to start the tractor in the spring. Regular charging with a smart charger can help prevent this.