A power supply unit for a utility vehicle, including: an electrical energy store; a generator; an interface to at least one electrical load of the utility vehicle; a power line unit to connect the energy store and the generator to the interface, wherein the power line unit includes a switch for electrically isolating the generator from the interface; and a sensor unit to detect a fault in the electrical energy store and/or in at least one line of the power line unit and/or in the generator and to respond to the detected fault by actuating the switch to isolate the generator from the interface, in particular wherein the electrical energy store remains electrically connected to the interface. Also described are a related method, controller, utility vehicle and computer readable medium.