The Bebop 2 (Power) controller will typically load your device when it is (USB-) connected to the controller. To find out whether this is still the case for low battery levels of the controller, I measured the input current when it is connected. Even though the android device is 100% charged the controller will still supply the current needed for your device display. Using bigger (android) devices will certainly deplete your controller faster. There also seems to be a Lithium-ion production version of the Skycontroller 2 on the market. I only tested the Lipo version of the controller.
