Why your MacBook battery drains overnight

A sleeping Mac uses much less power than an awake one, so a big overnight drop usually means it wasn’t asleep, or kept waking. The next morning, run pmset -g log | grep -E "Entering Sleep|Wake from|DarkWake from" in Terminal: each line shows when the Mac slept or woke, why, and the battery level. No “Entering Sleep” line means something held it awake; many “DarkWake” lines mean it kept waking for maintenance or the network. Wake for network access is in System Settings › Battery › Options.

Updated 11 November 2026 · commands checked on macOS 27.2

Read last night in the power log

macOS keeps a log of every sleep and wake. Reading it needs no administrator password.

Before you restart, open Terminal from Applications › Utilities.
Run pmset -g log | grep -E "Entering Sleep|Wake from|DarkWake from".
Find last night’s first “Entering Sleep” line and this morning’s “Wake from” line, and compare the Charge values.
Every “DarkWake from” line in between is a wake with the screen off. The number at the end of the line is how long it lasted.
If the evening has no “Entering Sleep” line at all, the Mac stayed awake. Find out what held it with the steps in Why won’t my Mac sleep?

pmset -g log | grep -E "Entering Sleep|Wake from|DarkWake from"

On our MacBook Pro, closed and on battery for an afternoon (shortened, the middle left out):

2026-11-11 13:55:57 +0200 Sleep                Entering Sleep state due to 'Clamshell Sleep':TCPKeepAlive=active Using Batt (Charge:100%) 162 secs
2026-11-11 13:58:39 +0200 DarkWake             DarkWake from Deep Idle [CDNP] : due to NUB.SPMI0Sw3IRQ nub-spmi0.0x02 rtc/Maintenance Using BATT (Charge:100%) 5 secs
2026-11-11 13:58:44 +0200 Sleep                Entering Sleep state due to 'Maintenance Sleep':TCPKeepAlive=active Using Batt (Charge:100%) 429 secs
…
2026-11-11 16:46:02 +0200 DarkWake             DarkWake from Deep Idle [CDNP] : due to NUB.SPMI0Sw3IRQ nub-spmi0.0x02 rtc/SleepService Using BATT (Charge:100%) 2 secs
2026-11-11 16:46:04 +0200 Sleep                Entering Sleep state due to 'Sleep Service Back to Sleep':TCPKeepAlive=active Using Batt (Charge:100%) 41 secs
2026-11-11 16:46:45 +0200 Wake                 Wake from Deep Idle [CDNVA] : due to smc.sysState.Wake(0x70070000) lid SMC.OutboxNotEmpty RTP.multi-touch/HID Activity Using BATT (Charge:100%)

Part of the line	What it means
`Sleep, DarkWake, Wake`	What happened. A DarkWake is a wake with the display off; a Wake is a full wake (on our Mac, “Display is turned on” was logged the same second).
`due to …`	The reason. ‘Clamshell Sleep’ means the lid was closed; ‘Maintenance Sleep’ and ‘Sleep Service Back to Sleep’ mean it went back to sleep after a dark wake.
`Using Batt (Charge:100%)`	Running on battery, and the battery level at that moment.
`162 secs`	How long that state lasted. 13:55:57 plus 162 seconds is 13:58:39, the time of the next wake.

For totals since the last startup:

pmset -g stats

Sleep Count:13
Dark Wake Count:12
User Wake Count:1

Here the Mac slept from 13:55 to 16:46, woke 12 times in the dark for a few seconds each, and the charge didn’t move. That’s a healthy night. A bad one looks different: hours with no “Entering Sleep” line, or dark wakes every few minutes that last a long time, with the charge dropping between them.

It never fell asleep

Apple’s energy tips put it plainly: even an app you aren’t using may be working in the background. Search the log for when the display turned off and when the Mac actually slept:

pmset -g log | grep -E "Display is turned|Entering Sleep"

2026-11-11 12:15:37 +0200 Notification         Display is turned off
2026-11-11 12:52:50 +0200 Notification         Display is turned on
2026-11-11 13:10:59 +0200 Notification         Display is turned off
2026-11-11 13:14:38 +0200 Notification         Display is turned on
2026-11-11 13:55:52 +0200 Notification         Display is turned off
2026-11-11 13:55:57 +0200 Sleep                Entering Sleep state due to 'Clamshell Sleep':TCPKeepAlive=active Using Batt (Charge:100%) 162 secs

At 12:15 the display went off, but there is no “Entering Sleep” until 13:55, when the lid was closed. For 37 minutes, from 12:15 to 12:52, the Mac sat awake with the screen dark: an Electron app was holding it. How to find the app.

Common culprits: a browser tab playing audio or video, a call app, an app that syncs, an Electron app that never lets go. Every process is explained in What keeps a Mac awake.

It kept waking up

Dark wakes are normal; macOS uses them for maintenance. Two settings add more:

Wake for network access lets other devices wake your Mac to use its shared resources, such as shared printers or Music playlists, and the Mac also wakes at regular intervals to tell the network those resources are available. On a Mac laptop it’s in System Settings › Battery › Options; choose Never if you don’t share anything. On a desktop, turn it off in Energy.

Power Nap keeps a sleeping Mac up to date. Apple says that on battery it checks Mail and updates Calendar and other iCloud events; on a power adapter it can also download software updates and make Time Machine backups. Apple’s macOS Tahoe guide puts it in System Settings › Battery › Options › Enable Power Nap; you may not see that option on every Mac.

To see how both are set, in Terminal:

pmset -g custom

On our Mac (shortened). The pmset man page says womp is the same as Wake for network access:

Battery Power:
 powernap             1
 womp                 0
AC Power:
 powernap             1
 womp                 1

Apple also suggests turning off sharing services you don’t need in System Settings › General › Sharing. Why each wake happened is in the log too: Why your Mac wakes up by itself.

The “Last night” report in SleepPilot

SleepPilot (Mac App Store) has a Last night report built from what it recorded while it was running: how long the Mac was asleep, how long it was awake while nobody was using it, which apps kept it awake, the wakes it saw, and how much the battery changed. It answers the same questions as the power log, by app name and without Terminal. It can also warn you when an app holds the Mac awake for longer than you set while nobody is using it.

Questions

How much charge should a MacBook lose overnight?

It depends on the Mac, the battery and what wakes it, so compare against your own good nights. As one example, our MacBook Pro slept almost three hours with the lid closed, woke 12 times in the dark for 2 to 30 seconds each, and the log showed 100% at both ends.

What is a DarkWake?

A wake with the display off, for maintenance, scheduled tasks or the network. The reason is at the end of the line. How to read wake reasons.

The log starts this morning. Where is last night?

On our Mac the power log began at the last restart. If you restarted, last night is gone; check the next morning before restarting.

Does the log say which app kept the Mac awake?

Not in the Sleep and Wake lines. The Assertions lines in the same log do: search it for the app name, or follow Why won’t my Mac sleep?

Is it worth disconnecting accessories at night?

Apple’s energy tips suggest disconnecting accessories and external drives you aren’t using, and its sleep troubleshooting mentions faulty USB or Thunderbolt devices as a cause of unexpected wakes.

Sources

Save energy on your Mac — Apple Support
If your Mac sleeps or wakes unexpectedly — Apple Support
Share your Mac resources when it’s in sleep — Apple Support
Turn Power Nap on or off on Mac (macOS Tahoe 26) — Apple Support
Change Battery settings on a Mac laptop — Apple Support
pmset(1) man page