Method for Controlling an On-Board Power Supply System for a Motor Vehicle, On-Board Power Supply System and Motor Vehicle

An on-board power supply system for a motor vehicle includes a high-voltage network with a high-voltage energy storage device, a main converter for converting the high-voltage into a predetermined low-voltage in the low-voltage voltage system for supplying voltage to low-voltage consumers, a battery management system, and a bypass converter assembly. The bypass converter assembly transfers a specific maximum permissible amount of energy from the high-voltage network to the low-voltage network during a parking phase of the motor vehicle.