Battery draining faster after macOS Tahoe 26.6 update on MacBook Air

Device: MacBook Air 13-inch, Apple M1 (2020)

Previous macOS: Sequoia

Current macOS: Tahoe 26.6

Issue: Faster battery drain despite Low Power Mode being enabled.

.Consider the age of the MacBook Air

The Apple M1 MacBook Air was first introduced in November 2020. Depending on its purchase date and usage, the battery may have accumulated several years of charge cycles. Lithium-ion batteries gradually lose capacity with age, potentially reducing runtime.

However, battery age alone does not explain why performance deteriorated after upgrading from Sequoia to Tahoe 26.6. Both battery health and software-related causes should be investigated before drawing conclusions.

Allow post-update activity to settle

After a macOS upgrade, background tasks such as Spotlight indexing, Photos analysis, iCloud synchronization, and application optimization may temporarily increase energy consumption.

• If the update was recent, allow 24–48 hours for background activity to settle, or longer if processing continues.
• Connect the Mac to power and Wi-Fi when convenient.
• Restart it once if you have not done so since updating.

If battery life improves, temporary background activity may have contributed to the problem. Otherwise, proceed to the next step.

Identify energy-intensive applications

Open Finder > Applications > Utilities > Activity Monitor >> Energy.

Look for applications with consistently high Energy Impact. Browsers, video-conferencing apps, cloud-sync utilities, and background applications may contribute to excessive consumption.

Next, check the CPU tab for processes that remain unusually busy. Processes such as mds_stores and mdworker_sharedmay indicate Spotlight indexing.

Quit unnecessary applications normally, update problematic apps, and retest battery performance.

Review battery usage history

Open Apple menu > System Settings > Battery and review the Last 24 Hours and Last 10 Days views, if available.

• Rapid drain during active use: Investigate applications, CPU activity, and display brightness.
• Drain while the lid is closed: Investigate sleep behaviour and connected peripherals.
• Drain while idle: Check background processes and software activity.

Conduct a one-hour test under your usual workload, recording the starting and ending battery percentages. Compare results under similar conditions.

Check actual battery health

Open System Settings > Battery > Battery Health.

Record:

• Condition: Normal or Service Recommended.
• Maximum Capacity: The percentage reported by macOS.

The current charge level of 86% is different from maximum capacity. Charge level indicates how much energy is currently available; maximum capacity estimates the battery's capacity relative to when it was new.

Reduced maximum capacity may explain shorter runtime on an older Mac. If battery condition is Normal and capacity remains relatively high, investigate software-related causes before considering battery replacement.

Optimize power settings

Since Low Power Mode is already enabled, verify that it is selected for battery operation under System Settings > Battery.

Also:

• Reduce screen brightness to a comfortable level.
• Close unnecessary applications and browser tabs.
• Review System Settings > General > Login Items & Extensions.
• Disconnect unnecessary USB accessories when testing battery drain during sleep.

Low Power Mode reduces energy consumption but cannot eliminate all background activity or compensate fully for a worn battery.

Check for software updates

Update applications through the App Store or their official developer websites.

Then open System Settings > General > Software Update and check for newer macOS updates offered for your Mac. Install relevant updates, restart, and repeat the battery test under comparable conditions.

Escalate if the problem persists

If battery drain remains excessive:

1. Temporarily quit nonessential third-party applications and retest.
2. Start the Mac in Safe Mode to help isolate software-related causes.
3. Run Apple Diagnostics if hardware problems are suspected.
4. Contact Apple Support if the issue continues, particularly if Battery Health reports Service Recommended.

Avoid erasing the Mac, reinstalling macOS, or downgrading to Sequoia as initial troubleshooting steps. Back up important data before considering major changes.

Conclusion

The M1 MacBook Air's introduction in November 2020 makes battery aging a relevant consideration. However, the timing of the increased drain after upgrading from Sequoia to Tahoe 26.6 also warrants investigating software and background activity.

Recommended approach: Check Activity Monitor, review battery usage history, and record Battery Condition and Maximum Capacity. These findings will help distinguish battery aging from post-update activity or a software issue before considering battery replacement.

Have the computer evaluated by the Professionals who have the Special Hardware Software and Expertise to diagnose the battery issue and offer possible solutions

Make an Appointment at the Apple Genius Bar or call 1 800 MyApple and have them evaluate the computer

Other location Call Centres 

 Contact Apple for support and service

It's been almost 3 months in updating macOS to Tahoe 26.6 before that the battery performance was alright. But i don't feel that battery is performing that well after the update. I consider your words regarding introduction of M1 MacBook Air was in 2020, But it was very good until the update i am feeling something wrong with the update it self. I also have a latest update of Tahoe version which is 26.7.1 as current OS is 26.6. Do i need to update it now?

And regarding the activities that you told me to check, I am jus uploading them here do check and guide me through what can be done if any thing is needed. As i don't have that relevant knowledge about that:)

[Edited by Moderator]