Electric power supply device, control method, and non-transitory storage medium

A control method executed by a computer of an electric power supply device installed in a vehicle, the control method comprising:

• determining a state of a main switch configured to operate a traveling system of the vehicle;
• switching a relay, disposed between a high-voltage battery and one or more pieces of in-vehicle equipment, on or off based on the state of the main switch;
• when the main switch is turned off while the relay is in an on state, determining whether a particular in-vehicle equipment configured to operate after the main switch is turned off is present among the one or more pieces of in-vehicle equipment;
• and
• when the particular in-vehicle equipment is present, supplying electric power from the high-voltage battery to the particular in-vehicle equipment while maintaining the relay in the on state.

A non-transitory computer-readable storage medium storing instructions that, when executed by one or more processors of a computer of an electric power supply device installed in a vehicle, cause the one or more processors to perform operations comprising:

• determining a state of a main switch configured to operate a traveling system of the vehicle;
• switching a relay, disposed between a high-voltage battery and one or more pieces of in-vehicle equipment, on or off based on the state of the main switch;
• when the main switch is turned off while the relay is in an on state, determining whether a particular in-vehicle equipment configured to operate after the main switch is turned off is present among the one or more pieces of in-vehicle equipment;
• and
• when the particular in-vehicle equipment is present, supplying electric power from the high-voltage battery to the particular in-vehicle equipment while maintaining the relay in the on state.