Each battery has a 5Wh, 1300mAh capacity and 3.85V output which allows you to record 135 minutes of 1080p30 video and 63 minutes of 4K60 video with the Osmo Action. It takes approximately 90 minutes to charge the battery from empty to full, and it takes approximately 130 minutes to simultaneously charge three batteries in the hub. The hub is powered by a separately available USB Type-C cable. Each battery case features a handy microSD card storage slot inside.