BATTERY REQUIREMENTS FOR UNINTERRUPTIBLE POWER-SUPPLY APPLICATIONS

There is an expanding market for small-to-medium capacity secondary batteries for use in uninterruptible power supplies (UPSs). UPSs are commonly used to provide protected power to computer installations, point-of sale terminals, and essential telecommunications equipment. The capacity of currently available UPSs is, typically, from 500 VA to several hundred kVa, with power-backup from ten minutes to one hour at full load. All UPSs incorporate secondary batteries; usually sealed lead/acid cells. Battery requirements include: high reliability; extended operating life; tolerance to extended float charging; and good, deep-discharge characteristics at high discharge rates. Recent research and development experiences in the design of a range of UPSs is described and the need for batteries optimised for UPS applications is highlighted.