A method for charging an auxiliary voltage source that provides power for at least one additional component, the additional component being in addition to an electric drive that is powered by a main voltage, is described. The method includes electrically connecting a protection and/or control circuit to the main voltage source via a DC-to-DC converter configured for power supply, and to the auxiliary voltage source via a reverse blocking valve. The method further includes electrically connecting the main voltage source to the auxiliary voltage source via a charging device. The method still further includes charging the auxiliary voltage source via the main voltage source.