Why my battery drains after update?

You know, after every ROM update, the first thing users complain about is the battery drain. For the first few days after update release, forums are filled with this issue and after a while this topic begins to be spoken less. Let’s explain the reason of it…

ROM updates are all about system changes (files are deleted, removed, renamed, relocated or updated) and it means that your device needs to adapt to all those changes, relearn the new paths, identify new processes and more important, get rid of the old cache files that are pointing to obsolete files.

All of these take time and more important, makes your device run slower, less efficient and consumes more battery… In due time, it will get to normal.

Is there something we can do to speed up that “learning process”?

Yes, there is;

1- Just run the cleaner tool to get rid of the obsolete cache files and terminate all the obsolete processes.
2- Update all your apps. (If updates are available)
3- You can also force close all your installed apps and clean their caches individually.
4- And finally, turn off the device and leave it for a couple of minutes. After this you can run the cleaner tool once again.

All of these will clean completely your device from “bad habits” and give it a new start.

Also, updates as big as MIUI 10 may mess with the battery sensors/readers, so I recommend you do a battery calibration:

1- Turn off your device and put it to charge until it reaches 100%.
2- Turn it on and if not showing 100%, leave it charging until it reaches 100%.
3- Use device as usual until it turns off completely.
4- Repeat the first two steps.

Hope this can help you to understand how updates work and more important, how to “get your device back”!

According to Google the Android operating system is a “Living Organism”, in a way that it learns with the users habits, optimizing itself along the way… The problem is, this learning curve takes about 2 to 3 weeks to achieve it’s fully optimized state.

As a summary for battery draining issues after Pie update:

Unless your device comes with native Android 9 the cache files are kept on memory (even the obsolete ones) for apps to use them. Discharging the device will make it discard all the processes that run on the background… And when you turn it on, the device will start from a near-to-clean state… Charging it while off, will achieve two things:

  1. Gives the device enough time to clear the memory.
  2. Will make a kind of battery calibration, removing any eventual misreading from the sensors.

Special thanks to @ollylopes for this valuable information.

See Battery Draining post for tips.