Abstract
The growing demand for reliable electricity in off-grid regions has driven the adoption of solar photovoltaic (PV)-based microgrids, yet system performance remains constrained by intermittency, suboptimal storage integration, and limited real-world validation in developing contexts. Existing studies often isolate PV generation, battery storage, and control strategies, with insufficient integrated optimization and empirical validation, particularly in rural African settings. This study presents a simulation-driven and experimentally validated optimization framework for a standalone PV–lithium-ion battery microgrid using Helioscope. A 1.6 kW PV array, 5.12 kWh LiFePO₄ battery, and 6 kW dual-MPPT hybrid inverter were designed for a residential off-grid system in Nigeria. Performance evaluation utilized meteorological data, validated load profiles, and field measurements for realistic operational assessment. Results indicate that PV string reconfiguration to match inverter MPPT voltage enhances energy harvesting efficiency. The lithium-ion battery system demonstrates superior voltage stability, higher usable capacity, and improved depth-of-discharge compared to conventional lead-acid systems. Helioscope simulation outputs show strong agreement with field measurements, with minor deviations attributed to irradiance and temperature fluctuations. The system achieved stable energy generation, effective load matching, and consistent performance across seasonal variations. The novelty of this study lies in the integrated optimization of PV configuration, lithium-ion battery sizing, and inverter MPPT coordination within a single validated simulation–experimental framework for rural Nigerian microgrids. Unlike prior work focused on isolated components or theoretical models, this approach provides system-level validation under real operating conditions. The findings confirm that simulation-validated lithium-ion PV microgrids improve reliability, efficiency, and scalability for rural electrification.

Key words: Helioscope simulation, Lithium-ion battery energy storage, Microgrid optimization, Rural electrification, Solar photovoltaic (PV).