<![CDATA[Off-grid photovoltaic (PV) systems require component sizing that is consistent with the daily load profile, available solar energy, storage autonomy, and protection requirements. This study developed a modular mathematical model and MATLAB-based calculator for preliminary capacity sizing of an off-grid PV system. The model calculated daily energy demand, PV array capacity, battery bank capacity, inverter rating, miniature circuit breaker (MCB) current, and a recommended solar charge controller (SCC) rating. The input case consisted of a 75 W refrigerator operated for 24 h, a 20 W lighting load operated for 13 h, and a 200 W water pump operated for 3 h. The assumed system parameters were 5 h/day peak sun hours, 80% system efficiency, 12 V DC bus voltage, 80% allowable depth of discharge, one day of autonomy, 350 Wp PV module rating, and 100 Ah battery unit rating. The MATLAB computation showed a total daily energy requirement of 2,660 Wh/day and a simultaneous load of 295 W. The required PV capacity was 665 Wp, rounded to two 350 Wp modules. The battery requirement was 277.08 Ah, rounded to three 100 Ah units. The inverter and MCB were calculated at 368.75 W and 30.73 A, respectively. The proposed calculator provides a practical, transparent, and educational tool for early-stage off-grid PV design]]>
Copyrights © 2026
