This article explains how to charge GoPro HERO cameras and GoPro batteries. The process is similar for other GoPro cameras, but may differ for older models.
To charge a GoPro battery with a charger, remove the battery from the camera. This procedure varies depending on the camera model. For example, for a GoPro HERO5 Black Edition, follow these steps:
Find the button on the bottom panel.
Press the button and slide the door to the side.