Abstract: A power supply assembly for a vehicle includes a generator connected to an engine of the vehicle; a high-voltage bus to which the output voltage of the generator is supplied and to which a high-voltage load is connected; a low-voltage bus connected to the high-voltage bus via a voltage step-down element and to which a starter motor and a low-voltage load are connected; a high-voltage storage cell which a positive terminal thereof is connected to the high-voltage bus and a negative terminal thereof is grounded via a switch element; a low-voltage storage cell which a positive terminal thereof is connected to the low-voltage bus via a key switch and a negative terminal thereof is grounded; and a controller for controlling the opening and closing of the switch element, wherein the controller is constructed so as to monitor the starting and stopping of the engine based on start and stop signals form the engine, and open the switch element when the stopping of the engine is detected.

Abstract: A car power supply system which can improve the installation freedom of an engine and safety against crash and obtain high output for a large-capacity electric load. The car power supply system comprising: first and second generators which are smaller in size than a generator which is large in size and obtains high output for a large-capacity electric load by itself; and a controller which causes the first generator to generate power by the start of an engine and causes the second generator to generate power when it detects that a vehicle is braked, wherein high output is obtained for the large-capacity electric load with the first and second generators.