Valve-regulated lead/acid batteries for modular installation

Valve-regulated lead/acid (VRLA) batteries are particularly suitable for the modular installation of power supplies to support modern telecommunications equipment. These provide the high reliability demanded by digital loop carrier systems through the use of constructional features designed to meet service conditions over the full lifetime of the battery. Higher levels of packaged energy have been obtained and battery designs have been optimised for extended life in floating service. VRLA batteries are available in various types that are specially adapted to particular installations and duty cycles. The use of thinner plates will provide good performance at higher discharge rates as well as being able to provide power for longer discharges, but places additional demands on the design to achieve the durability required. Packaging requirements need to be considered for ease of installation and for some systems need to be ruggedised for easy handling. In this paper, the ways in which these conflicting requirements can be met by careful attention to all aspects of design are discussed and operational experience with various types of VRLA battery is reviewed