What is a VRLA Battery Bank?
The full form of VRLA is “Valve Regulated Lead Acid”. Therefore, a VRLA battery means a Valve-Regulated Lead-Acid battery. It is essentially a modified version of a conventional low-maintenance lead-acid battery.
Overchargings form oxygen and hydrogen gases due to electrolysis of water. These gases escape through vents provided on the top of the conventional battery cells. This hydrogen and oxygen loss leads to water loss. So we need to top up water periodically in conventional lead-acid battery cells. A VRLA battery cell does not allow gases to escape easily. The oxygen combines with the hydrogen to form water again. Because of this recombination cycle, we normally do not need to add water from outside.
However, a VRLA battery includes a safety relief valve on the container. This valve opens only when internal pressure rises due to abnormal charging conditions. It releases excess gas to prevent damage or explosion. Because of this valve, we call it a Valve-Regulated Lead-Acid (VRLA) battery.