The expected duration is 2 to 2.5 hours of battery life for the cameras with the removable battery on a full charge.
We recommend carrying fully charged spare batteries if you expect to have extended filming sessions.
You can provide continuous power to the camera if you need to record for longer than that by using a Contour brand wall charger or the Contour brand car charger. Both are designed specifically to supply continuous power to the camera while also charging the internal battery.
There are available from your local Contour retailer. If you are in the USA, the chargers can be found at our online store here: http://store.contour.com/power-c2.aspx