Abstract: A non-contact charging method, in which a battery-powered device is set down on a charging platform, a power receiving coil in the battery-powered device is electromagnetically coupled to a power transmission coil in the charging platform, power is transmitted from the power transmission coil to the power receiving coil by electromagnetic induction, and a battery (52) in the battery-powered device is charged. The charging current of the battery is detected on the battery-powered device side, the transmission efficiency is detected from the detected charging current, the detected transmission efficiency is compared to an efficiency threshold value, it is determined that a foreign object is on the charging platform when the detected charging efficiency is less than the efficiency threshold value and it is determined that a foreign object is not on the charging platform when the detected charging efficiency is greater than the efficiency threshold value.

Abstract: An output connector 20 includes a power supply terminal portion 20A? and a data terminal portion 20A?. The power supply terminal portion 20A? can supply a current required for a battery-driven device connected to the output connector 20. The data terminal portion 20A? can switch the terminal voltage of this data terminal portion 20A? between different voltages based on a current which is drawn by the battery-driven device through the power supply terminal portion 20A?. A power supply control circuit can detect the current value of current which is drawn by battery-driven devices so that the battery pack can switch the data terminal portion based on the detected data between the different voltages. Therefore, even single battery pack can supply electric power to a plurality of types of battery-driven devices.

Abstract: A device housing a battery 50 has charging terminals 72 for connection of a charging adapter 80 and a contactless charging section 60. A charging apparatus 10 performs contactless charging of the device housing a battery 50 placed on the charging apparatus 10. The device housing a battery 50 is provided with a charging apparatus detection section 61 that detects placement on the charging apparatus 10, an adapter detection section 62 that detects charging adapter 80 connection or charging, and a charging selection section 63 that selects internal battery 52 charging by either the charging apparatus 10 or the charging adapter 80. When the device housing a battery 50 is placed on the charging apparatus 10 and the charging adapter 80 is connected, the charging selection section 63 controls either the charging apparatus 10 or the charging adapter 80 to charge the internal battery 52.