Yeah...This is the WORST battery issue I have had with an Apple product in recent memory, and I own at least (1) device in every major product category Apple currently offers!
My 45mm Series 9 just turned 1 year old last week and until these latest 11.0 and 11.01 updates I was more than satisfied with the battery life. I have always charged my watch back up to 100% at around 5:30PM every night with about 15% to 25% battery charge remaining when I would place the watch on my charger stand most days.
Now I am getting battery charge alerts hours before the usual charge time with often less than 10% battery remaining as early as 3:30PM! The watch can not currently make it through a full 24 hour period without coming very very close to being at 0% charge remaining! Since I am not usually back at home until after 5PM, there is no simple way to charge my watch back up so much earlier than my usual 5:30PM schedule. Apple really needs to get to the bottom of this ASAP since the current situation has destroyed my Apple Watch's viability as my daily driver!
And before anyone chimes in with the usual finger pointing away from the actual cause of the issue at hand...
I have changed NOTHING on my watch in terms of software and typical use case. The only thing that has changed has been the recent update to 11.0 and then recently to 11.01. This situation is not sustainable for the majority of us out here who rely heavily on this product's ability to run a full 24 hours between charges!!!