Design and Performance Evaluation of a Smart Charging System for Lithium-Ion Batteries in Standalone PV Applications

The growing adoption of distributed renewable energy systems necessitates efficient battery charging strategies for reliable energy storage. This paper presents a smart charging system for lithium-ion batteries in standalone photovoltaic (PV) applications. The system integrates a 2.2 kW PV array with a high-efficiency buck converter and employs an optimized Perturb and Observe (P&O) algorithm for maximum power point tracking (MPPT). A microcontroller-based multistage charging strategy, featuring bulk, absorption, and float stages, is implemented to enhance battery lifespan and charging efficiency. Comprehensive MATLAB/Simulink simulations demonstrate 99 % MPPT accuracy, 97 % charging efficiency, and a 15 % reduction in battery temperature variation compared to conventional methods. The proposed solution offers a robust and efficient charging approach, particularly suitable for rural electrification and off-grid applications.