MacBook Air M1 (macOS Sonoma) discharging overnight

Tech Support
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The last couple of weeks my MacBook Air M1 is (almost) completely discharging overnight (from full to empty). The battery is healthy and at 97% of its maximum capacity. I haven’t detected a pattern yet, but I think it might only be happening when the MacBook was connected to an external monitor and a smart power plug which I both switch off at night (and if I only lock my Mac and close the lid; not shutting it down).

What might be causing the battery to drain overnight? What can I do to prevent this?

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Activity monitor will show you what programs have used the most energy in the past 12 hours. That might give you a clue if something needs to be shut down at night.

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Safari “95” and iTerm 2 “44”, but I’m not sure what to do with this info.

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You’re not making the Mac hibernate/sleep, so something you have open in Safari is remaining active and using the battery., as is iTerm 2.

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I used Sleep Aid - View a Mac's sleeping habits, solve issues, improve battery life, stop sniffers to find out why my mac wasn’t sleeping.

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That’s an interesting app!

I have downloaded it and started my 14 day trial to see whether I can find the root cause.

It immediately lists Amphetamine as an application that prevents idle sleep… However, I have enabled “Allow system sleep when display is closed” in Amphetamine’s settings (checkmark set).

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Lost 30% overnight; this is Sleep Aid’s report:

Started	30 Jan '25 at 23:35:39
Ended	31 Jan '25 at 07:17:12
Duration	7 hr, 41 min, 33 sec
Power	Battery Power
Battery	-30,8% (-4,0% per hour).
Insomnia	32 count (4,2 per hour).
	7 min, 8 sec (1,5%)
Woken by	ATC0.USBWakeup smc.70070000 USB-C_plug
Sleep by	Clamshell Sleep

and:

Bluetooth Ache

Started	30 Jan '25 at 23:42:18
Ended	30 Jan '25 at 23:42:25
Duration	7 sec
Woken by	Bluetooth
Sleep by	Maintenance Sleep

7 Minutes of activity should not explain -30%?

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Maybe Sleep Aid’s warning is about when the lid is open?

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It looks like something attached via the USB C is waking the machine.

What happens if you disconnect everything else before shutting it.

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The Mac stayed at 100%! (I checked at 8:00 in the morning and 19:00 in the evening, before using the Mac for the first time today)

Sleep Aid still complains about “Excessive Insomnia” though…

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So either your Dock or something connected to your dock is causing the Mac to work.

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Yes, I think it might be the ethernet network cable in that dock.

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Try disconnecting only the ethernet tonight?

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That’s indeed my next step.

Or disabling Wi-Fi during sleep using Sleep Aid, but I currently am unable to do that due to a bug in that application… (I can’t select it because it overlaps with the Power Adapter / Battery switch)

Sleep Aid@2x
Sleep Aid@2x1348×1252 174 KB

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@aardy Do you still use it? What does normal Mac sleep look like?

Although my Mac does not seem to drain during the night, if I unplug all cables, Sleep Aid still complains about excessive Insomnia (about 9 minutes in 8 hours of sleep).

Most of it is caused by “wifibt”. I found a way to get to the overlapped option (see previous post) by using the keyboard (and also contacted one of the authors on Bluesky, who posted a link to a beta that should solve this UI issue), but get a warning that disabling this during sleep will also disable “Find my”…

Now I’m in doubt what to do (might try it one night).