FarmCam Mobility comes with a rechargeable battery that has a capacity of 7800 mAh/3.6V. In standby mode, a fully charged battery can last for about 2 months. When you have the camera in use the battery time will be shorter since watching live feed, playback or configuations of the camera consumes more power. If you contiuously watch live feed or recodnings from the camera the battery will last 500 min. 

Also, if PIR and recordning is activated (activated by default) then motion events triggers the camera to wake up and record the event. An advice to save battery time is to set a schedule for PIR so it's only active during times of the day you are interested in. If the camera is used for monitoring animals and recording isn't necessary it's good to inactivate PIR to save power:

An example: if the camera is triggered by motion 5 times per day, 5 times per night and records 15 seconds per event and live feeds 6 times per day for 20 seconds each time, then a fully charged battery will on average last 4 weeks. 

You can follow the battery level by selecting settings --> Battery

There you can find the battery level during the last 30 days.