EXPERIMENTAL STUDY OF SOLAR LEAD-ACID BATTERY CHARGING EFFICIENCY UNDER VARYING CONDITIONS

This study presents an in-depth experimental investigation into the charging performance of 12-volt photovoltaic (PV) solar panels with lead-acid batteries under diverse atmospheric conditions. The research aims to evaluate how variations in solar irradiance, temperature, and cloud cover influence the charging efficiency and long-term stability of both functional and non-functional 12 V 130 Ah lead-acid batteries. A solar charging system was assembled using four 100 W panels connected in parallel and monitored under real outdoor conditions. Voltage data were recorded at thirty-minute intervals for both types of batteries, enabling a comparative assessment of their performance in clear and cloudy weather. The results demonstrated that the functional battery exhibited steady voltage growth and reached its target charge within two hours under clear skies, while cloudy conditions extended the charging duration to four hours. Conversely, the non-functional battery showed irregular voltage fluctuations and a pronounced decline in charging capacity, confirming its inability to store energy effectively. Mathematical models were formulated to describe the voltage–time relationships for each scenario, revealing charging rates of 0.644 V/h and 0.405 V/h under clear and cloudy skies, respectively. Additionally, post-charging relaxation analysis showed that the functional battery maintained voltage stability, whereas the non-functional battery experienced a continuous drop of 0.342 V/h, indicating internal degradation. The findings underscore the strong dependency of solar charging performance on meteorological conditions and battery health, highlighting the importance of effective charge control strategies and battery maintenance in optimizing solar energy storage and extending battery lifespan.