Arsenal 2 has its own internal power supply, so it doesn't rely on your camera for power or charging.
Depending on the shooting mode you select, Arsenal 2 may increase your camera's own power consumption (e.g. by constantly focusing the lens in Handheld Mode). However, this only occurs when you're actively using Arsenal 2. Most modes will not significantly impact your camera's battery life.
When Arsenal 2 isn't being used, it automatically disables the USB connection to prevent it from draining any power from your camera.