S21 FE Battery drain

[pjtwyman]

I have a S21 FE phone with the Exynos chip, purchased new November 2022. I have only used it regularly since Nov 2024, my primary phone being a Pixel which broke after the Android 15 update. Previous to last November I only used it occasionally, mainly updating apps and security updates. I am now noticing the battery seems to be draining fast. Measures I have taken to resolve this include:

Disabling 5G mobile data
Restricting refresh rate to 60hz
Slow charging most of the time
No Bluetooth and enabling location only when a specific app requires it
Using Dark Mode
Reducing background activity by Sleeping about 30 seldom used apps
AOD is disabled
I always power the phone off at about midnight and turn it on at about 7-9am.
I factory reset the phone and reinstalled everything from Google Drive

And I even had the battery replaced yesterday at an Authorised Repairer who assured me the battery genuine Samsung and new.

Nevertheless it does not seem to have improved. I switched it on at 7.30 this morning at 100% and by 3pm it is 65%. During this time it was powered off for 2 hours during a movie and has been used to browse, read emails and news apps and listen to music (with screen off, wired earphones).

No games, videos etc.

The battery settings are a little confusing. It says Screen on time of 1hr 53 min and battery usage of 25%. This latter figure doesnt make sense as the battery is at 65% down from 100% i.e. 35% usage.

I would appreciate any advice to explain and or resolve the issue.

 

[mustang7757]

Hello
How long ago did u do the factory reset? Because it will take a week to start learning usage patterns.
Do you have a lot of 3rd party apps download?
Check device care under care report and app issues?
Can try safe mode for a couple days but you will only use native apps in that mode as it disables 3rd party and u can't power it off otherwise you exit that mode.

 

[pjtwyman]

I did the reset about 2 weeks ago. The new battery was only put in yesterday. Perhaps it needs more time to sort itself out.

According to Device Care there are no app issues and there are. None issues in the last 30 days.

 

[magenta]

Mobile data uses alot of battery over wifi. Also in low signal it can be troublesome, switching to 2g when using wifi tends to help.

 

[B. Diddy]

I moved this from the S22 forum to the S21 forum.

 

[mustang7757]

I did the reset about 2 weeks ago. The new battery was only put in yesterday. Perhaps it needs more time to sort itself out.

According to Device Care there are no app issues and there are. None issues in the last 30 days.

New battery definitely needs to learn the usage pattern , wasn't it factory reset when they did the repair?

 

[pjtwyman]

No they didn't factory reset it when replacing the battery.

Sorry about late reply.