I have an iPhone SE and Series 3 Watch. My battery life seems terrible on the SE, i have done various things like hard reboot etc. Can't see any apps in particular causing an issue. I am assuming iOS11 is the issue (plus my battery health is 88% so i guess i should expect 12% less usage). I wanted to try to wipe the phone and start from scratch (rather then restoring). I should get my health data back from iCloud, but how does the watch bit work - it is backed up to the phone right? How do i keep all the activity stuff - or is that all packaged up in the iCloud health sync? I assume i have to re-pair the watch when the phone is wiped - does this mean the watch loses all data?