 VRLA battery

A valve regulated lead acid battery (VRLA 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 valve that retains the battery contents independent of the position of the cells.There are two primary types of VRLA batteries, absorbent glass mat (AGM) and gel cell.