MacBook Pro M1 Max overnight battery drain in Sleep Mode

A 50% battery loss overnight while a MacBook Pro with an M1 Max is asleep is not normal. 

Even with 93% battery health, a 16-inch MacBook Pro should typically lose only 1% to 5% over 8 to 12 hours in Sleep Mode. 

A loss of 50% almost always indicates that the Mac is either not remaining asleep or that a background process is preventing deep sleep.

The fact that this only began during the past few weeks makes it reasonable to consider a change introduced by a recent macOS update, although the update itself is not necessarily the direct cause. 

Though the latest version of macOS is 26.5.2. Learn how to update the software on your Mac and how to allow important background updates.

More commonly, an update changes the behaviour of a driver, an application, Spotlight indexing, iCloud synchronization, or power management.

Leaving a 950-page Pages document open should not cause this problem. 

Pages is designed to remain suspended during sleep, and a text-only document, even one approaching 1,000 pages, uses very little power once the Mac is asleep.

The most likely causes, in roughly the order I would investigate them, are:

1. The Mac is repeatedly waking from sleep because of a background task.
2. A process is preventing the system from entering deep sleep.
3. Network activity, iCloud syncing, or Power Nap-like functions are waking the computer.
4. An external device or Bluetooth accessory is waking the Mac.
5. A software bug introduced by a recent macOS update. Though there is nothing specifically mentioned by Apple regarding Tahoe 26.5.2

The first thing I would examine is the battery usage history.

Open System Settings > Battery and look at the battery graph.

If the graph shows periods labeled Screen On or Screen Idle during the night when the Mac should have been asleep, then the computer is waking repeatedly instead of remaining asleep.

Next, determine what actually happened while the Mac was asleep.

Open Terminal and enter:

pmset -g log | grep -i "Wake"

The command often reveal exactly what caused each wake event, such as:

1. Bluetooth
2. Power Management
3. Network
4. USB device
5. lid open
6. maintenance wake
7. DarkWake

If you see dozens or hundreds of wake events overnight, that would explain the battery drain.

Another useful command is:

pmset -g assertions

If anything is preventing normal sleep, this command will often identify the responsible process.

Common examples include cloud synchronization services, media applications, backup software, or virtualization software.

If the problem began immediately after updating to macOS 26.5, Spotlight may also still be indexing. You can check this by using watching CPU activity in Activity Monitor.

I would also temporarily disable the following settings for one night as a test:

1. Wake for network access
2. Bluetooth devices allowed to wake the computer (disconnect any Bluetooth mouse or keyboard if practical)
3. Any USB hubs or external drives
4. Any SD cards or external accessories

Then put the Mac to sleep and compare the overnight battery loss.

One additional possibility is that the notebook is not actually entering sleep because a background process is holding a power assertion. 

This has occasionally occurred after macOS updates, where a system process or third-party application inadvertently prevents deep sleep. 

Download the Application Etrecheck  ( External Link ) directly from the Developer.

This is a Diagnostic Tool that makes no changes to the computer.

It makes a coherent and readable inventory of both the Hardware and Software used on the computer 

The application is free or paid for added features. 

The Report will Not Reveal Any Personal Information. 

Post back the Full Report - Share Report >> Copy , then  paste  >>>> using the Additional Text Icon  <<<<

Based on your description, my leading suspicion is that the Mac is experiencing repeated DarkWake events or another process preventing deep sleep, rather than a failing battery. 

A battery at 93% health would not suddenly begin losing half its charge overnight solely because of normal aging. The sleep logs and pmset output should identify the underlying cause.

I apologize for my previous post.

I was focused primarily on the battery issue and did not consider the Mac as a whole.

Aside from the fact that "The book is currently around 950 pages in length, but it doesn't have any images, video, or graphics, so it's just text." is being left open while the Mac is in Sleep mode, there are many other factors that can affect battery usage.

The important question is: what else is installed, configured, and running on this 16-inch MacBook Pro (M1 Max) with macOS 26.5?

I'd like to thank @sberman for reminding me about EtreCheck, a diagnostic application developed and maintained by fellow contributor @etresoft.

Rather than trying to diagnose the issue through a long series of questions, I recommend downloading EtreCheck directly from the developer.

EtreCheck is a diagnostic tool that does not make any changes to your Mac.

It produces a clear, well-organized inventory of both the hardware and software on the system, making it much easier to identify potential causes of unexpected behaviour.

The application is available as a free download, with optional paid features for those who need them.

The generated report does not contain personal information.

Please post the complete report by selecting Share Report >> Copy, then paste the contents into your reply using the Additional Text (<> ) icon.

Having the full report will help avoid unnecessary back-and-forth and provide a much better foundation for troubleshooting.

See especially “Additional Options” - the third, fourth and fifth options here.

Change Battery settings on a Mac laptop - Apple Support

Norse Son wrote:

• I am Mac savvy, having been so since my first MacSE, but I am not a techno-nerd, so I tried the easier choices first. I don't know how helpful they have been, though, because of the different changes I experimented with

I turned off Network Access while asleep.

• I disabled Automatic Software Updates.

• I couldn't find the Power Nap feature under battery in Tahoe 26.5.2.

• I quit Pages before putting my laptop to sleep or shutting it down.

• And I've been shutting down overnight instead of putting it to sleep.

•

I have noticed that that 950 page document in Pages does act slowly as I type in changes, sometimes taking several seconds to show the change.

• But then I saw the same refresh delay during a Google AI session today, where the longer it continued it took several seconds to post answers to the new question I asked. But that could just be Google AI.

• So with all that going on I'm wondering if it's a quirk (or bug) that got baked into the latest update to Pages.

Pretty easy to overlook: Have you tried restarting the Mac? How long has it been since it was last restarted? To find out open Terminal and type: uptime

Sluggishness can also be a case of the virtual memory manager thrashing. Open the Activity Monitor, click on Memory. What color is the memory gauge? If it isn’t green thrashing is a likely cause. And with a document that long thrashing is a good possibility. And click on the Memory column heading to see which apps are using the most RAM.

Another divergent work-around bears mentioning as part of this discussion.

That computer is a battery-CAPABLE device, It is not optimized as a battery-operated device (it is not an iPhone.)

Your computer performs best when connected to AC power, such as the power adapter. It can use the full output of the Power Adapter AND when doing especially challenging work could also freely "borrow" power from the battery. In some cases, even with the power adapter connected, the charged state may decline during very stressful work.

When used only on battery, your computer has no extra cushion of power, and may perform more slowly. However, for ordinary non-stressful tasks this may not be objectionable (possibly not even noticeable.)

In general, you should ALWAYS connect a power source when it is possible to do so, and only run on batteries (which could be somewhat slower) when no power sources are at hand. Modern Macs maintain optimum battery charge levels under program control, and will NEVER over-charge. Connected to Power is NOT necessarily charging.

When you set it down in one place, or set it down for the night, Plug it in. Then you won’t CARE whether it would drain the battery.

Owl-53 wrote:

Picking Up the Void, left my a certain un-name 👻'ed individual

Let’s see - who might that individual be? Me, perhaps? What are the odds? 100%?

You did provide a really nice analysis. But putting my response down was inappropriate and offensive. Not all people who post questions here are computer professionals. Not all will choose to use Terminal or Etrecheck. Many will seek simpler solutions, especially as first steps. They will try things out of Apple’s playbook before plowing through thirty paragraphs of admittedly helpful, useful material.

Your original post was fine. The part that is far from fine is the last paragraph in your response to Lawrence Finch.

sberman wrote:

Owl-53 wrote:

Picking Up the Void, left my a certain un-name 👻'ed individual

Let’s see - who might that individual be? Me, perhaps? What are the odds? 100%?

I’m sure it is not you; I’m pretty sure I know who it is.

sberman wrote:

Owl-53 wrote:

Let’s see - who might that individual be? Me, perhaps? What are the odds? 100%?

Hum

There is nothing in your posting that remotely resembles the Ghosted individual

As a Matter Off Fact, the Ghosted Individuals posting was Moderated OUT

As for my Original Post, that too was moderated out

So there is no need to be defensive

As for putting down the link you provided

There was no direct or indirect reference to any person or link at all

I do hope we can co-exist on this question

If not Say the word and I am out of here

sberman wrote:

OK, thanks for the clarification.

Yes, co-existence works.

Apparently I missed seeing the ghosted individual’s posting.

No issues, whatsoever 👍

As I am generally not on the ASC post 12 Noon

Would you be willing to handle the latest post from the Author

Just so they can make some realistic head way on their issue

Owl-53 wrote:

No issues, whatsoever 👍

Good, same here.

Would you be willing to handle the latest post from the Author Just so they can make some realistic head way on their issue

Well, the original post appeared four days ago, so it appears speedy responses are not an especially important criterion. All reasonable responses are undoubtedly welcome. I’ll consider what, if anything to suggest next.

Several thoughts:

Norse Son wrote:

• I couldn't find the Power Nap feature under battery in Tahoe 26.5.2.

Did you scroll down once you got to System Settings > Battery?

You then commented about slow performance in both Pages and Google AI. See especially the first two bullets here. Perhaps disk space or free memory are issues.

If your Mac runs slowly - Apple Support

Sometimes and this maybe one of those times, where the most obviously gets overlooked \

Or, as one of my old bosses used to say " Keep it simple stupid " KISS method for solving problems

Good work there, as usual 👍

🦉-53

Really nice analysis.

Lawrence Finch wrote:

Really nice analysis.

Thank you 👍

Picking Up the Void, left my a certain un-name 👻'ed individual