Finding the cause of a battery drain
If you experiencing battery drain issue when the lid is closed. We can see the logs by executing this command:
pmset -g log|grep -e " Sleep " -e " Wake "
One of the possible cause for recent OSX is: “Find My Mac” operates even when the lid is closed. It will try to connect to known wi-fi and then send its position accordingly. It can be disable by executing this command:
sudo pmset -b tcpkeepalive 0
References: