A portable power charger having an internal rechargeable battery is provided with a power connection port than can act in a power input mode when the charger is connected with an external power source via the power connection port and in a power output mode when at least one electronic device is connected to the charger via the power connection port. The power charger may be connected with both an external power source and an electronic device via the power connection port at the same time, wherein the charge supplied from the external power source recharges the charger and any electronic device connected to the charger. The charger also can automatically turn on if a connector cable is connected to the power connection port with either an external power supply or an electronic device connected at the other end of the cable to supply or draw power through the cable.