MacBook battery drain issue after shutdown — is this normal?

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MacBook battery drain issue after shutdown — is this normal?

Hi everyone,

I’ve been experiencing something strange with my MacBook’s battery. My device is MacBook Pro 2020 M1. Battery health is %89 and Cycle Count is 136. After I properly shut it down, I still notice battery drain when I leave it unplugged and keep storing in backpack. For example:

Overnight, I see around 4% drop even though the device is completely shut down.
The most extreme case I observed: after leaving it off for 6 days, the battery went down to 18%.

There isn't even a hairline scratch on the laptop; it hasn't been damaged or dented.

I think the problem is software-related. Apple Diagnostics didn't find any issues. I installed macOS 26 today, and I hope that solves the problem. Do you know of any other settings I should adjust?

Is this behavior expected for MacBooks, or should I be worried about a possible hardware/software issue?

Thanks in advance for your insights!

MacBook Pro 13″, macOS 26.0

Posted on Sep 16, 2025 07:07 AM

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Answer 1

Sep 16, 2025 08:24 AM in response to demolon

On an Intel system, the System Management Controller (SMC) runs stuff like fan speeds, clock rates, sleeping, waking, and charging. if it gets confused, an SMC reset is supposed to set it straight.

on M-series Macs, one of the processors must remain sleepy but awake to maintain these same items. that will use a small amount of power. There is no true OFF.

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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. Activate Battery Health Management and do not spend another moment of your time thinking about charging.

When you set it down in one place or for the night, plug it in. Then you won't CARE whether it would drain the battery when nominally asleep.

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