This paper presents a smart battery charger based on the cascaded boost-buck converter supplied by a photovoltaic (PV) panel. This topology offers a great advantage since it operates in boost mode when the battery voltage is higher than the PV output voltage and operates in buck mode when the battery voltage is lower than the PV voltage output. Due to the presence of inductances at input and output of the cascaded boost-buck converter, the currents across the PV panel and the battery presented very low ripples. In this work, the control of the two converters is simplified since they are driven simultaneously within a same duty cycle. This reduces the implementation cost and complexity. The proposed battery charger operates intelligently; depending on the sun irradiance level and the battery state of charge, the algorithm automatically switches to maximum power point tracking mode, constant current mode, constant voltage mode, or floating charging mode. To verify the overall operation of the system, numerical simulations are performed for two battery voltage levels and including the different phases of charges. According to the obtained good results, the suggested smart charger can be inserted as battery management device in PV energy system.