MacBook battery drain issue after shutdown — is this normal?

The battery is utilized to keep the internal clock running and to keep track of certain settings. Even the power on button needs a small amount of energy to work properly, when you go to power on. Losing ~ 4% over 24 hours is not unusual in my experience. If it seems to be worsening over time significantly, that could be a sign that the battery is aging or even failing, despite the other indicators that it is healthy.

Your Mac is 5 years old, so a battery that old may be losing some of its reserves. Still, it looks like you have at least several more years use you can expect to get so your best bet is to connect it to power whenever you can, that way the battery will be used less. Batteries are consumables, in other words they have only so many discharge and charge cycles in their lifetime so the less you "use" the battery the longer it will last.

kungmo wrote:

My M1 MacBook Air has battery drain problem after updating MacOS 26 Tahoe, too. Battery drains 3~4 percent per day. This problem must be fixed.

The same thing happens on MacOS 15 and not specific to Tahoe. Your Mac is never truly off, just like your cable box is never shut off. Even TV's now remain on to perform updates when shut off. When near power and not needed for mobility, plug that Mac in.

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.

My M1 MacBook Air has battery drain problem after updating MacOS 26 Tahoe, too. Battery drains 3~4 percent per day. This problem must be fixed.