In this thesis, the design and implementation of a stand-alone photovoltaic interleaved SEPIC (Single-Ended Primary Inductance Converter) charger is studied. The system architecture includes a photovoltaic module, an interleaved SEPIC converter, a microcontroller, and a lead-acid battery. The SEPIC is a non-isolating DC-DC converter, and works as a major part of this stand-alone photovoltaic charger. The SEPIC has both step-down and step-up functions. Two SEPIC are interleaved operation, they are used in photovoltaic module to charge a lead-acid battery under constant voltage. The charger is controlled by a microcontroller. Furthermore, all the auxiliary powers needed to control circuit is provided by photovoltaic module itself.