My Garmin Vivoactive 4 which has been running fine until last few days has started to drain the battery in about 6 hours or less. For a day or so it also had no lights on the back and would not show the heart rate but that has suddenly come back on. I have tried turning watch off and resetting and hard reset, checked what I have running but nothing makes a difference. Usually lasts for days without charging - has anyone got any suggestions?