battery draining issue after installaiton of windows 11

I am also having the same issue.  In fact I have found the battery drained 40% when the laptop was off.  I unplugged it at 12pm today, left it with it's lid shut, it's not been turned on for a few days.  When I came to turn it on battery was just 60%.  I looked at usage and it said fully charged at midday and then 'system' has used 37%.  How?  It was off and closed.  Now after just 30 minutes of web browsing, battery is down to 39% with a single tab open in Firefox.  I am running a 2 year old Dell XPS 15 9570 and battery life was ok before the upgrade to W11 build 22463.100, I was on W10 21H1 before.