Abstract: An adapter battery unit for backup powering of a video camera device comprises a battery unit electrically and selectively connectable to an electronic device and is electrically and selectively connectable with a backup battery device. The adapter battery unit can be connected to the backup battery pack during operation of the electronic device without interruption in the power flow to the electronic device. In operation, the adapter battery unit supplies power to the camera device during normal operation of the camera. However, as the main battery in the adapter battery unit becomes discharged, a backup battery may be attached to the adapter battery without interrupting flow of power to the electronic device. In addition, when the adapter battery is connected to an external a/c power source, the adapter battery becomes charged and also acts as a charger to charge up the backup battery.