S21 Overnight Battery Drain

[mmtech]

I have seen battery drain overnight in S21 even if you have restricted everything still 10-15% battery drains in 8 hours. When checked in Battery & Device care it shows

Google Play Store : 0.7%

Gmail: 0.2%

one UI: 0.2%

This total is around 1% then where remaining battery goes ?

This is really weird, is there a way to find out what else is draining battery taking 14% battery overnight?

Also i kept phone in Safe Mode overnight just to be sure no hidden third party app drains battery but result is still the same 12% battery drain.

I have been pixel and iphone user in past but never seen more than 5% battery drain overnight. Is battery used is cheap quality or poor wiring.

Any one else facing it ?

[mmtech]

I tried all options disable all background services, location, Bluetooth and whatever possible. Just my phone is connected to cell tower that's it. No Internet. Still overnight battery drain is 10%

It's just that my phone has dual physical sim and that was the reason buying Samsung instead of Apple. But seems Samsung hardware is still not capable to handle cell reception which apple and old feature phones are able to handle very well. I thought returning back to Samsung after 10 years would have changed something but I was wrong. Samsung still the same. Battery sucking machine.

[mmtech]

I tried all options disable all background services, location, Bluetooth and whatever possible. Just my phone is connected to cell tower that's it. No Internet. Still overnight battery drain is 10% in 8 hours. It's just that my phone has dual physical sim and that was the reason buying Samsung instead of Apple. But seems Samsung hardware is still not capable to handle cell reception which apple and old feature phones are able to handle very well. I thought returning back to Samsung after 10 years would have changed something but I was wrong. Samsung still the same. Battery sucking machine.

[jkalltheway]

To cut a MULTI YEAR LONG story short, I could/can never get ANY of my (expensive!!) Samsung Galaxy flagship devices (S8, S9, S10+, S20U, S21U, Note 8/9/10+, Note 20U, etc) to drain less than 3-4% per hour, and overnight, I lose 14-18% in 7 hours despite ALL the tricks in the book.  And yes, I HAVE seen all the videos over the years, all the Reddit post, blogs, etc, nothing works.  In terms of SOT, I average just about 3h SOT in a 13-15 hr day with my S21U, and about 2.5-3 in my previous N20U.

May be I'm just incredibly stupid for coming back to Samsung flagships year after year band expecting better results in this department each time.  I've all but given up, the stress is just too much; may be it's just my bad karma !  If the battery was 6000mah (like in the F62), may be that'd work.  If not, I really really doubt I'd be going again for their next flagship.

My other phones like the Asus Zenfone 8, Pixel 4XL and iPhone 11 don't drain more than 1% an hour and I'm completely ok with that. 3-4% is just too much.  Yes, I have 500 or so apps, but they are the same apps in the other phones as well and I use all of them the same way, and they all deal with it just fine.  Also, and very importantly, I do NOT need to waste my precious spare time doing a million tweaks each time I get a Samsung phone to get, in the end, a below average battery life !

[mmtech]

Seeing your comments I get bit of relief. Mine drains 10% battery overnight but I have less than 100 apps. Why Samsung unable to fix long running battery drain and overheating issues?
They are good in hardware but unable to create optimized software even after so many years.
This is my last mistake to buy Samsung flagship phone. Next time only Google or Apple. Will say Bye Bye to Samsung forever next year.

[-7-]

Read the whole thread. So did you find a fix for that battery drain issue. I have the same problem. 

I have also watched multiple battery saving tip videos but I am seeing 10-15% drop every night. Made bixby turn off mobile data, wifi, Bluetooth and location, and turn on power saving mode and close all apps at 00:10 to 06:50.  Same result. 

I am thinking of resetting all settings to factory setting. 

I have a widget that shows instantaneous battery drain. On my LG phone I used to get around 120mA during normal usage in battery saving mode. The s21 drains over 200mA normally. 

How is your phone now.  Did u fix the issue?

[-7-]

Ah I didn't see the discussion on airplane mode so weak signal is the issue. Will try switching to 2G overnight with bixby routines.  And I can also use another sim. Will post here my findings.

[mmtech]

I tried factory reset as well as all tips given online. Still the same. The main culprit is network reception which is poor in S21. I did side by side comparison with my other phones including Samsung A50 as well. All were better with stable network reception. S21 being unstable network reception draining battery badly on standby.

[-7-]

Hey I have been experimenting with this phone. 

1) I tried going with Airplane mode ON for one night with all apps closed - Zero drop all night

2) Last night 1 hour after Bixby routine activation to turn on power saving mode, airplane mode and closing all apps. I found that the battery was still draining. I checked it was in power saving mode and in airplane mode. But all the apps I was using was not closed and they were using battery..Even in power saving mode and with sleeping apps turned on. I closed all apps and for the next 7 hours no drain whatsoever. 

[mmtech]

That's obvious. As I mentioned in previous comment that the main culprit of battery drain is poor network reception in s21. So airplane mode will not drain more that 3% battery overnight

[mmtech · Accepted solution]

I was able to solve the issue by changing my network from o2 to Vodafone and guess what, battery drain is reduced by 50%.
Previously it was 12% in 8 hours night standby and now 6% which is expected.