Comparative Assessment of Absorbed Glass Mat, Gel, and Flooded Lead-Acid Batteries based on Charging and Retention Performances under Variable Load Conditions

In photovoltaic (PV) systems, particularly in off-grid applications common in developing regions, lead-acid battery performance is a critical determinant of overall system reliability and efficiency. Hence, the objective of this paper was to perform a comparative assessment of three-lead acid batteries-absorbed glass mat (AGM), Gel, and Flooded-based on their charging and retention performance under variable load conditions using standard techniques. Results revealed that AGM batteries consistently outperformed their counterparts, demonstrating superior voltage stability under high loads, the lowest self-discharge rate, and minimal maintenance requirements. Gel batteries offered moderate performance, particularly under low-to-medium load conditions, while Flooded batteries, although fastest to recharge, experienced the highest voltage drop during discharge and self-discharge periods. These findings underscore the importance of informed battery selection in PV system design, especially for rural electrification where reliability and maintenance constraints are pivotal.