A decade of progress with valve-regulated lead/acid batteries

The construction and operation of two types of valve-regulated lead/acid (VRLA) cells are described, both using absorptive glass mat separators. Various failure modes have been identified over a period of time but it is shown that many of these have been eliminated through design and improved processing. As a result, predicted design lives are being achieved and reliable operation is assured. The importance of battery monitoring is also examined. Cell voltages, current, time and temperature are readily measured and the data stored for subsequent interrogation or for immediate fault indication. These systems can improve overall reliability. Future directions for the development of VRLA batteries are outlined