Design of a Solar PV–Battery System for EV Charging

Abstract

South Africa’s EV market is growing faster than its charging infrastructure can keep up. Loadshedding and an already strained national grid make grid-tied charging stations unreliable, which is what motivated this work. This paper describes the design and simulation of an off-grid solar PV system that uses a backup battery bank to charge electric vehicles independently of the grid. To make the simulation meaningful, the EV itself was modelled as a battery with a state of charge rather than as a simple load. This allowed realistic charge and discharge cycles to be tested under varying solar conditions. The system brings together a PV array using Kyocera Solar KC200GT modules, an MPPT controller to extract maximum available power, a boost converter, and DC-DC converters that handle the interconnection between the storage battery and the EV battery. The entire system was built and simulated in MATLAB. The results showed that the storage battery and EV battery both behaved as expected through charge and discharge cycles, and the system managed energy flow between them without significant losses. While this is a simulation study and further hardware validation would be needed, the findings suggest that off-grid solar charging is technically feasible and worth serious consideration as South Africa looks for practical ways to scale its EV infrastructure without waiting on grid improvements.