Loses large amt power while closed/asleep/.

If it's a setting, then you are likely the person making the setting, so check all your settings. However, the usual cause of this problem is a running process that has crashed, or runs throughout the time due to Energy Saver preferences. Check them out. Check for bad processes using Activity Monitor.

Using Activity Monitor

     Use Activity Monitor on your Mac

     Runaway applications can shorten battery runtime, affect performance, and increase heat and fan activity.

Using Activity Monitor Part 1- CPU and Memory

Using Activity Monitor Part 2- Energy, Disk, and Network

Hello!

Start Activity Monitor (/Applications/Utilities/Activity Monitor.app), select Energy tab and you will see application list. Sort this list by Energy Impact (second column) and perhaps you will get an answer.