So the Gear VR doesn't have a battery to charge. The Note 4's USB port plugs into the Gear VR so the touchpad, back button and volume up and down can be operated from the right side of the Gear VR. To run Google Cardboard apps just flip the USB plug out of the way and pair a BT controller or mouse or keyboard and you are set, that doubles your VR apps. Depending on the game, the Note 4 battery could die after an hour or two so the alternative I have come up with is using the ZeroLemon 10,000mAh battery taped to the Note 4. I haven't had to use it yet but can if I need.
I really like the Gear VR for a bunch of reasons the least of which is the total immersion. It is awesome.
Here is a good review of Dreadhalls
http://youtu.be/IEvEOl6VLPg