Patent ID: 8643212

Claim:
A power supply apparatus for a vehicle, comprising: a main power supply that includes a power generator driven by an engine to generate electric power, and a battery, wherein the power generator and the battery are connected in parallel to each other; a subsidiary power supply that is connected in parallel to a circuit that connects the main power supply to a specific electric load, wherein the subsidiary power supply is charged with the electric power output from the main power supply, and the subsidiary power supply assists supply of the electric power to the specific electric load using the electric power with which the subsidiary power supply is charged; a charge current limiting portion that limits a charge current that flows to the subsidiary power supply to a value equal to or smaller than an upper limit value; a decelerating-state detection portion that detects a decelerating state of a vehicle; and an upper limit current setting portion that sets the upper limit value based on the decelerating state of the vehicle detected by the decelerating-state detection portion so that when the vehicle is decelerating, the upper limit value is larger than the upper limit value when the vehicle is not decelerating.