Valve-Regulated Lead-Acid Batteries : Elsevier : 9780444507464 : 0444507469 : 01 Jan 2004 : For many decades, the lead-acid battery has been the most widely used energy-storage device for medium- and large-scale applications (approximately 100Wh and above). In recent years, the traditional, flooded design of the battery has begun to be replaced by an alternative design. This version - the valve-regulated lead-acid (VRLA) battery - requires no replenishment of the water content of the electrolyte solution, does not spill liquids, and can be used in any desired orientation. Since the VRLA battery operates in a somewhat different manner from its flooded counterpart, considerable technological development has been necessary to meet the exacting performance requirements of the full range of applications in which rechargeable batteries are used. The valve-regulated design is now well established in the industrial battery sector, and also appears set to be adopted widely for automotive duty.