US Patent 9490654 Non-contact charging method

In a non-contact charging method, a battery-equipped device is set on a charging stand, and a power reception coil of the battery-equipped device is electromagnetically coupled to a power transmission coil of the charging stand, and power is transmitted from the power transmission coil to the power reception coil by an electromagnetic induction action, and a battery of the battery-equipped device is charged by power induced to the power reception coil. Furthermore, in the non-contact charging method, charging current of the battery is detected at the battery-equipped device side, the detected charging current is compared with a current change determination threshold, and it is determined that a foreign object is set on the charging stand when the charging current is less than the current change determination threshold, and it is determined that the foreign object is not set in the charging stand when the charging current is greater than the current change determination threshold.