Patent ID: 8768554

Claim:
An in-vehicle power supply device for use in a vehicle including an engine and a load, the in-vehicle power supply device comprising: an electric generator configured to be connected electrically with the load; a main power supply connected electrically with the electric generator; a DC/DC converter; a power storage unit connected with the electric generator via the DC/DC converter, the storage unit being configured to be connected with the load via the DC/DC converter; and a controller for controlling the DC/DC converter, wherein the DC/DC converter is operable to: charge the power storage unit with regenerative electric power generated by the electric generator to store the regenerative electric power in the power storage unit; and discharge the stored regenerative electric power from the power storage unit to the main power supply and the load, and wherein the controller is operable to: stop the DC/DC converter when a charging-status value indicating a charging status of the power storage unit is not larger than a predetermined lower limit value; operate the DC/DC converter when the charging-status value is larger than the lower limit value and the vehicle ends deceleration; and operate the DC/DC converter when a speed of the vehicle is not lower than a predetermined speed and an accelerator position of the engine is not larger than a predetermined accelerator position, even if the charging-status value is not larger than the predetermined lower limit value and the vehicle is not in a deceleration state.