OverviewHistoryBasic principleConstructionAbsorbent glass mat (AGM)Gel batteryApplicationsComparison with flooded lead–acid cells
A valve regulated lead–acid (VRLA) battery, commonly known as a sealed lead–acid (SLA) battery, is a type of lead–acid battery characterized by a limited amount of electrolyte ("starved" electrolyte) absorbed in a plate separator or formed into a gel; proportioning of the negative and positive plates so that oxygen recombination is facilitated within the cell; and the presence of a relief