Highlighted
Active Level 3
usual..
Extended usage in cold environments can result in temporarily reduced battery performance. Your battery will recover when it warms up again. 
 Continuous charging over long periods can slightly reduce battery life . If you do not plan to use your phone for a while,we recommend charging to at least 80% ,then turning off the phone and storing it at room temperature. To maintain battery performane, charge your phone at least once every 6 mounths.