For people having this issue do this in terminal:
log show | grep 'Wake reason' | grep '2018-12' (or if you want specific date, then grep specific date like 2018-12-10)
You will see why laptop wakes up and will be able to eliminate that reason, in my case I had this issue with laptop not sleeping and I found up that it was constantly woken up by bluetooth interaction, so I went to settings and disabled wake up on bluetooth thing and it solved the issue.
Just had MacBook in Sleep for a good half a day and it has spent 2% battery total.