Empirical study of Decentralized group-based Battery Energy Management (DBEM) for PV-battery nanogrid systems in islanded mode

Abstract Conventional battery management systems struggle to optimize the control of battery fleets with varying capacities and states of charge, resulting in reduced lifespan and inefficient renewable energy utilization, especially under dynamic loading and generation conditions in nanogrids. This paper proposes a decentralized group-based battery energy management (DBEM) system to address these challenges. The DBEM system was empirically validated using a prototype islanded nanogrid at Kasetsart University Sriracha Campus, Thailand, featuring three systems, each equipped with a 3.25 kWp photovoltaic array and 1200 Ah, 48 V battery groups comprising lead-acid and lithium-ion types. DBEM organizes batteries with similar characteristics into groups managed by a centralized controller, which optimizes charging and discharging processes in real-time. Empirical results demonstrate that DBEM significantly improves energy efficiency and prolongs battery lifespan, highlighting its potential to improve the performance of islanded nanogrid photovoltaic-battery systems.