I just love how Apple thinks it knows my day better than me. Love putting on my new watch and it be only charged to 80% when I will be away from home and chargers all day.

@shep You can turn off optimized charging on the watch and other devices too. There are a few other options too, explained here: support.apple.com/en-us/HT2...

I've turned it off on all devices but I also tend to micro manage it myself. As I understand it battery health is prolonged if the battery is generally below 80%. The longer a battery sits at 90% or higher the quicker it degrades. So for people that charge over night, night after night, if the battery gets to 100% by midnight and stays there for 6 hours, battery health degrades much more quickly. So Apple, in theory, is trying to learn each user's pattern and adjust to do the final 20% charge at the last minute.