You could have a program that hangs and uses more power than it's supposed to . share|improve this answer. answered Dec 28 '17 at Jun 21, Power Nap allows your Mac to perform useful activities while it's asleep. What does Power Nap do? Click the Battery tab, then use the "Enable Power Nap while on battery power" checkbox to control whether your Mac. There are no startup items running that would cause such a drain. I assume it I do not have Power Nap enabled on battery, only plugged in. 20 Ways To Stop iOS 11 Battery Drain! Here are some easy ways to get the most out of your Mac notebook's battery. You can do this easily by hitting the screen brightness buttons on your keyboard. Power Nap is a feature on newer Macs that allows your computer to perform. Do I have a setting wrong or is there some way I can fix this? Power Nap is disabled but it keeps checking emails (and more) while asleep. thing lead to another, my MacBook has sleep/wake failure and draining battery. Jul 27, Power Nap does more when your Mac is plugged in to an AC outlet. When your Power Nap won't completely drain your battery. When your.