Depending on what you have installed and how much of your OneDrive you've chose to sync, it can take Windows 48-72 hours to finish indexing and optimizing which will impact battery life. I was getting 4-6 the first two days, yesterday I was on battery for 8.5 hours running from meeting to meeting.
Also, if you install Chrome it will reduce battery life by 25-50%.
Just if you have Chrome installed - or if you have it running?