Vehicle charging system and vehicle charging method

A vehicle charging method for charging a charging system disposed in a vehicle,

• wherein the charging system includes:
• a drive battery for supplying power to a running motor of the vehicle;
• an auxiliary battery for supplying power to auxiliary equipment of the vehicle;
• and a drive battery charging device for charging the drive battery by receiving power from an external power source,
• wherein the drive battery charging device includes:
• a control section;
• and a power source circuit for supplying power to the control section,
• the vehicle charging method comprising:
• connecting the power source circuit to a plurality of power sources including the external power source;
• detecting an effective power source among the plurality of power sources;
• switching connection between each of the plurality of power sources and the control section so that the detected effective power source has a highest priority;
• supplying power from the effective power source to the control section;
• and
• charging the drive battery by a use of the power from the external power source under control of the control section.