Performance Analysis of a Battery-Buffered Solar Charging System for Low-Power DC Loads

Abstract

The rapid depletion of conventional energy resources and the growing demand for electrical power have increased the need for portable and sustainable charging solutions. Solar energy provides a promising renewable option for powering low-power electronic devices. This study presents the performance analysis of a battery-buffered solar charging system designed to supply regulated 5 V DC power for low-power loads. The system consists of a 12 V, 30 W solar photovoltaic panel for energy harvesting, a 12 V, 2 Ah rechargeable battery for energy storage, and a DC–DC buck converter for voltage regulation. Experimental tests were conducted under natural sunlight conditions to evaluate key performance parameters, including charging current, battery charging time, output voltage stability, and overall energy conversion efficiency. Results indicate that the solar panel delivered an average current of approximately 1.5 A under irradiance levels between 600 and 800 W/m². The battery reached full charge within about 2 hours, storing roughly 24 Wh of energy. The system maintained a regulated 5 V output with voltage variations within ±0.2 V at load currents up to 2 A. The overall system efficiency, calculated from the solar panel output to the regulated load output and accounting for losses in the charge controller, battery storage process, and DC–DC converter, was approximately 69%. These findings demonstrate that the proposed system provides a simple and reliable solution for portable low-power DC applications, particularly in off-grid environments where access to conventional electricity is limited.