Efficiency assessment of a photovoltaic energy storage system based on a 5 kVA bidirectional inverter and a 48 V / 4.8 kWh LiFePO4 battery

Abstract

The efficiency of an energy storage system with photovoltaic (PV) generation, installed in a home in the Autonomous City of Buenos Aires, is evaluated based on monitoring data from 2024. The system consists of a 5 kVA bidirectional inverter, a 48 V / 4.8 kWh LiFePO4 (LFP) battery, and PV generation coupled to alternating current (1.9 kWp) and direct current (1.1 kWp), and is configured to operate in self-consumption mode. The average annual efficiency was 95.4 % for direct current to alternating current conversion, 92.6 % for alternating current to direct current conversion, and 96 % for battery charge/discharge cycles, resulting in an overall system efficiency of 92 %. The use of storage systems associated with PV generation allows energy to be managed, increasing self-consumption, reducing grid consumption, and cutting peaks, which is key in electrical systems with high PV generation penetration.