Charge regimes for valve-regulated lead-acid batteries: Performance overview inclusive of temperature compensation
The main battery type employed in standby applications is the valve-regulated lead-acid (VRLA) battery. Float charging is normally used to maintain the battery in its fully charged state, however, float charging has limitations that can damage the battery and shorten its life. New charge regimes have evolved in recent years to tackle the intrinsic problems of float charging. The intermittent charge (IC) regime and the interrupted charge control (ICC) regime have been developed to prolong the service life of the battery in standby applications. The battery is normally maintained in the standby mode for a long period of time and there are infrequent discharge tests to verify the efficacy of the battery. Hence, the service life of the battery is highly correlated to its charge regime. This paper reviews the charge regimes for VRLA batteries, and assesses their charging performance and their impact on the service life of the battery. Recognising that temperature plays a significant role in battery operation, temperature compensation schemes are described for different charge regimes.