Investigation of charging and discharging characteristics of lead-acid batteries

Abstract

Rechargeable batteries are often used in off-grid power systems to enhance uninterrupted power requirements. They have become popular in Sri Lankan households in the recent past due to continuous power failures and many people tried to move to off-grid solar power systems via rechargeable batteries instead of popular on-grid solar power systems. Various batteries exhibit different voltage and current characteristics during charging and discharging. Secondary batteries can be charged using various battery charging techniques depending on the application. Furthermore, charging characteristics of a battery significantly enhances the performance as well as the durability. A rechargeable battery has specific conditions for charging. When the charging voltage and current are not in the recommended range, the battery performance may be reduced, and sometimes the battery may be seriously damaged. Due to the lack of centralized power networks, some on-grid energy sources have been replaced with lead-acid batteries. The main objective of the proposed study is to investigate the charging and discharging characteristics of lead-acid batteries, experimentally as well as analytically using different charging techniques. Three types of fundamental charging methods; (i) constant voltage method, (ii) constant current method, and (iii) constant current/voltage method, were carried out and analyzed in this study. Based on experimental and analytical results, the constant current/voltage method is found to be more appropriate for the battery charging process because it charges a battery quickly while maintaining its health.