Charge Estimation of Selected Rechargeable Batteries in the Nigerian Market

Abstract

Deep Cycle Batteries are used in renewable energy systems that require

the storage of electricity. Many challenges remain unsolved to

characterize and manage the battery. Among them, one fundamental

issue is the estimation of state of charge (SoC). SoC, expressed in

percentage, refers to the amount of capacity available in a battery. The

aim of this research is to carry out State of Charge Estimation of some

selected Rechargeable lead-acid batteries available in the Nigerian

market, using the open circuit voltage method. The batteries were

selected based on affordability and availability in the Nigerian market.

The SoC of three selected 100AH rechargeable batteries was estimated

from open circuit voltage method, by using data obtained from controlled

charging and discharging of the batteries under review, for the three

batteries considered, graphs of open circuit voltage versus SoC and

discharge curve were developed. Results from analysis of the developed

curves, would guide battery users in making informed decision before

purchasing any of the batteries reviewed. It was observed that mercury

has the highest operating voltage range, with that of Safepower battery

the lowest.