A merchandise display security device for a portable electronic device having an internal power source is provided. The merchandise display security device includes a sensor configured to be secured to the portable electronic device and to be in electrical communication with an external power source. The sensor is further configured to determine whether to transfer power to the internal power source. The merchandise display security device also includes a flexible circuit in electrical communication with the internal power source and the sensor. The flexible circuit is configured to transfer power provided to the sensor to the internal power source.