All Drift batteries are charged via USB while inside the camera. But if you have a second battery, you can't charge it while you're busy shooting with the camera.

With this kit you can...

The charging module accepts both the standard battery and the long-life battery. Just plug it into the AC wall charger or the 12V in-car adapter and the standard battery will be fully charged in 2 hours.

The in-car charger will also power the camera if required.

So with two or more batteries, one is always charging and you can keep shooting all day.