Do you have Power Nap enabled? That feature lets the Mac turn back on every so often to check for updates and other stuff, and can be a pretty big drain on your

Do you have Power Nap enabled? That feature lets the Mac turn back on every so often to check for updates and other stuff, and can be a pretty big drain on your battery. Otherwise, this is basically the difference between "sleep" and "hibernate". Hibernate shuts down and takes no power, sleep does require the computer stay powered on. When you close the lid of a Macbook, it sleeps, not hibernates.