A method for producing energy supply devices for providing electrical energy for a motor vehicle, wherein each of the energy supply devices has an energy supply unit arranged in a housing, wherein the energy supply unit is electrically connected to an energy source and to a transmission device designed to establish a safety extra-low voltage connection, wherein the energy supply unit can be controlled by a control unit for supplying the energy to the motor vehicle, wherein for a portion of the energy supply devices, a further energy supply unit is arranged in the housing and is electrically connected to the energy source and can be electrically connected to the motor vehicle, wherein the control unit is designed for controlling the further energy supply unit.