I am curious....if wifi is only used for activity upload for the most part, does it turn on only after you save an activity to upload and then shut off on its own? If not, how much of an effect does it have on battery life?
It just turns on when its needed. For example if you do manual upload over WiFi or set auto upload after activity finished. When the transmission ends it switches of WiFi. Otherwise, that would kill the watch in less then one day.