The battery charger (C) for electric vehicles comprises a voltage converter (DC/DC CONV), a power factor correction circuit (PFC) connected upstream of the voltage converter (DC/DC CONV), a controller circuit (PFC CNTR) operatively connected to the correction circuit (PFC) and suitable for piloting the correction circuit (PFC) for the correction of the power factor in the battery charger (C), a retroaction line (L) connected to the output of the voltage converter (DC/DC CONV) and to an input of the controller circuit (PFC CNTR), wherein the controller circuit (PFC CNTR) is suitable for varying the output voltage (VPFC) of the correction circuit (PFC) within a predefined voltage interval and according to the output voltage (VDCOUT) of the voltage converter (DC/DC CONV), in order to let the voltage converter (DC/DC CONV) operate as much as possible around the point of maximum efficiency.