Battery Capacity Calculation Method of a Stationary Battery for an Emergency Power Supply

Abstract

A storage battery is used as an emergency power supply that stores energy and supplies the stored energy to the load when necessary. While stationary lead-acid batteries were used in the past, lithium-ion batteries are being increasingly used in recent times, yielding improved efficiency. There are two methods to calculate the capacity of stationary lead-acid batteries, domestically and internationally. One is from IEEE Std. 485, conforming to KEPIC EEG 1200, and the other is from the design criteria of a construction-based electrical installation that quoted SBA S 0601. First, to calculate the capacity of a stationary lead-acid battery (for using emergency power), I compared both methods and analyzed their differences, modifications, and capacity calculations. Subsequently, I demonstrated the gaps between the two methods using actual calculations by applying the duty cycle from IEEE Std. 485-2020 and the Kt-T curve by the manufacturer. Based on these results, I finally reviewed the approaches to calculate the capacity of lithium-ion batteries and proposed an effective method.