How to Fix Battery Drain Issue in macOS Big Sur?
Like any other operating system available on the market, macOS Big Sur was also beta-tested for the most common issues & bugs, before finally releasing it for public use. While the OS was thoroughly tested to avoid any inconvenience to users, still it has some bugs & issues that manage to creep through. Battery draining fast in macOS Big Sur is one such issue that many users have encountered after upgrading to this latest operating system for Mac by Apple. You may also notice that MacBook getting very hot and fans working hard to keep them cool.
Why does battery drain faster after an update?
Some CPU intensive tasks such as re-indexing the Spotlight database and other file databases, including Photos’ library is one major issue why battery drain faster in macOS Big Sur. During these tasks, processor drives hard and consumes more energy, draining the battery faster.
Another reason behind battery draining fast is related to process called “kernelmanagerd”. Here, this process is consuming a lot of CPU cycles consuming more energy.
What is “kernelmanagerd”?
Kernelmanagerd is a process designed to manage kernel extensions, or kexts, in third-party applications. It is possible that certain third-party apps are facing issue with kernel extensions. It makes Kernelmanagerd to work hard to resolve them. Thus, it consumes a lot of CPU cycles.
How to identify if the kernelmanagerd process is causing trouble?
- Select Applications > Utilities and launch Activity Monitor.
- To order processes by the CPY cycles the are using click the CPU column.
- Check kernelmanagerd process.
- If it is consuming over or close to 70% of CPU cycles, then this is the reason behind battery drain.

How to fix battery draining fast issue in macOS Big Sur?
Spotlight indexing the disk could lead to fast battery draining. New indexing could last up to two days consuming a lot of energy. You need to check if Spotlight is still indexing by following these steps:
- Click on the Spotlight.
- Type a couple of characters into the search bar.
- If it displays “indexing…” in the progress bar, then Spotlight is still indexing, consuming igher number of CPU cycles.
Now all that you can do is to wait to complete indexing by Spotlight. Once it is done, your battery will be back to normal.
If you found kernelmanagerd process is consuming more CPU cycles, then you should consider uninstalling all unnecessary programs from your Mac. It will help you free up valuable device resources and release pressure from them as many third-party software run in the background unnecessarily.
To uninstall unwanted programs, you can use the best app uninstaller software for Mac.
Reduce the load on the CPU
To reduce to load on the CPU, you should consider managing login items. Login items are programs & processes that run in the background when you boot your Mac. Many of these processes run unnecessarily, thus it is always a good idea to reduce login items. To do this, open System Preferences > Users & Groups. Now select and disable all unnecessary apps that run at startup.

Another thing you should try is to reduce the browser tabs. If you open a lot of browser tabs unnecessarily while working, then remember they are consuming more RAM and CPU cycles. Simply close all unnecessary browser tabs to save CPU cycles and draining battery life. This especially important to close unnecessary tabs, if you’re using Google Chrome.

Conclusion
So these were few quick solutions to fix battery draining fast in macOS Big Sur. Do try these steps and share your experience in the comments below.
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