The main objective of this paper is to present to design of an on-board charger with the aim of charging a plug-in vehicle battery. This charger is able to control the values of the load voltage and current and then, maintain them at a desirable value. A first converter is used to convert the grid 50 Hz electrical quantities into dc quantities. A second converter adjusts the levels to the values required by the battery and moreover, provides a galvanic isolation. The control of the first converter is realized by using a power factor corrector. The control of the second converter allows supplying the battery with correct voltage and current values. This method is one of the most efficient to design an electronic supply with a low current harmonic impact to the grid. The choice of the structure and the choice of the components are explained. Determination of the efficiency of the on-board charger, loading cost and loading time needed is investigated in this paper.