In this paper, we present a high-speed battery charger, powered by a photovoltaic (PV) module array, for a LiFePO4 battery as a solar energy storage device. With a battery charging strategy, the presented battery charger involves a buck converter as the core equipped with a simple maximum-power-point (MPP) tracker. Considering complexity reduction and easy hardware implementation, a constant-voltage MPP tracking approach is adopted such that the maximum amount of output power can be delivered to the load in response to an arbitrary change in the level of solar radiation. A two-stage charging strategy, with temperature monitoring in a constant current mode followed by a constant voltage mode, is employed in such a way that the battery charge process can be markedly accelerated, while the damage caused by overcharging can be prevented. Finally, the performance of the proposed energy storage system using low-cost voltage, current, and temperature sensors for a PV and battery hybrid system is validated experimentally.