A connection base is disclosed. The connection base includes a first connection port, a second connection port, a charging unit, a first electric power conversion unit, and a second electric power conversion unit. The first electric power conversion unit is for converting an input voltage to a first output voltage, and for transmitting the first output voltage to the charging unit. The charging unit is for receiving the first output voltage and outputting a charging voltage, in order to charge the electric power bank device which is detachably connected to the first connection port. The second electric power conversion unit is for receiving and converting a second output voltage of the electric power bank device to a supply voltage, and sending the supply voltage to the inverter which is detachably connected to the second connection port.