US Patent 10173614 Power supply device for auxiliary device battery

A vehicle mounted charger converts external power into drive power, and supplies the power to a drive battery. A first converter supplies the power to an auxiliary device battery by converting the external power into the power for an auxiliary device. A second converter supplies the power to the auxiliary device battery by converting the drive power which is stored in the drive battery into the power for the auxiliary device. In a normal charging mode, the auxiliary device battery is charged by the first converter. Moreover, in a travelling mode or a rapid charging mode, the auxiliary device battery is charged by the second converter.