Wide scale use of the newly emergent VRLA (valve-regulated lead-acid) battery in telecommunication applications and the subsequent problems encountered early in their deployment history spurred intense efforts to improve the design as a continuous endeavor. After implementing improvements to battery placement and containment design to prevent the sudden onset of thermal runaway, the focus of the development work has been on cell internals. These include improved grid and strap alloys, superior AGM (absorbent glass mat) separator that retains compression in the cell, use of beneficial additives to the active materials and the need to avoid contaminants that promote detrimental side reactions. These improvements are now resulting in a vastly superior VRLA experience in the telecommunication applications. To further improve the reliability demanded by today's communication and internet environment VRLA battery installations should include continuous cell/module and system monitoring similar to that incorporated in competing advanced battery systems under development. (C) 2006 Published by Elsevier B.V.