Vehicle electrical power system with defect detection

A vehicular apparatus that receives power from a battery mounted on a vehicle, comprising:

• a main power supply circuit, of which a minimum operating voltage that enables power supply is lower than a rated voltage of the battery;
• a main controller configured to receive the power supply from the main power supply circuit;
• a defect detection unit configured to detect a defect;
• a recording unit configured to record defect information that specifies a content of the defect detected by the defect detection unit in response to the defect detection unit detecting the defect;
• a voltage detection circuit configured to detect a voltage from the battery;
• an operation controller configured to control an operation of a target device among a plurality of devices controlled by the main controller, the target device of which an operation is turned off at a voltage drop in response to the voltage from the battery detected by the voltage detection circuit becoming equal to or lower than a predetermined threshold value;
• and
• an auxiliary power supply circuit having a minimum operating voltage higher than a minimum operating voltage which the main power supply circuit has,
• wherein:
• in response to the operation controller turning off the operation of the target device, the operation controller is configured to notify the defect detection unit that the operation of the target device is turned off;
• in response to the defect detection unit being notified by the operation controller that the operation of the target device is turned off, the defect detection unit is configured to cancel a determination of the defect relative to the target device;
• the defect detection unit and the recording unit are electrically connected to the main power supply circuit;
• the target device is electrically connected to the auxiliary power supply circuit;
• the voltage detection circuit and the operation controller are configured to receive the power supply from the battery;
• the operation controller is configured to control a start and a stop of the power supply from the main power supply circuit and to control a start and a stop of the power supply from the auxiliary power supply circuit;
• and
• in response to the voltage from the battery becoming equal to or lower than the threshold value, the operation controller is configured to turn off the operation of the target device by stopping the power supply from the auxiliary power supply circuit.