VRLA (Valve Regulated Lead Acid) batteries

In a VRLA- Valve Regulated Lead Acid battery, the battery lid is sealed and each cell has a safety valve plug, which regulates the release of gas. If the gas pressure is within safety limits the gas produced will be kept inside the battery and converted back into electrolyte. If the safety limit is exceeded the valves will open to release the gas. This ensures an extremely low water loss.

A VRLA battery must never be opened. Trying to open the lid or plugs will cause damage to the encapsulation.

Both GEL and AGM batteries are of the type VRLA (Valve Regulated Lead Acid).