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]

Already tried bixby routines. Whatever I do the battery drain cannot be reduced to less than 10% overnight.

[Pugs1957]

Doing this is just to check if it's a signal issue, it's not a solution. Let us know how it goes. BTW do you clear your system cache after any updates?

[mmtech]

You are right. It's signal issue. Overnight battery drain in Airplane mode is 2%. Is this a hardware issue?
This is same sim and network which was there in my previous iPhone but there battery drain was negligible there?

[Fiona26]

Sorry I couldn't be much help. I only lost 2% last night. Using bixby routines. I set a certain time for my phone to go into battery saving mode and flight mode. If you tried all this I really don't know what the high drain is.

[mmtech]

My IPhone used to handle all these hassles automatically and never puts phone to airplane mode.
Why would you turn on Airplane mode and what if someone wants to call you in emergency then you will be unavailable.

[mmtech]

I also tried Bixby routine to switch to power saving mode and the battery drain was still 12% in 8 hours overnight as most of my apps are already deep sleeping so power saving didn't made any difference.

Also do not disturb was on during this time and location i turn off always.

The main difference was Airplane Mode. I turned it on and Battery drain was 2% in 8 hours.

So its kind of switch off phone when not in use. Samsung should learn something from Apple how to optimize battery for basic phone features like Network cell standby.

[Pugs1957]

It may be a hardware issue ie a fault or that the S21 in general requires a stronger signal. If you have WiFi calling, try turning that on overnight.

[5ta1da]

What about good old reboot?

Resolved similar unspecific issues couple times for me.

[mmtech]

Tried already. Seems there is no software issues. Could be Samsung puts cheaper hardware compared to iphones which are not able to handle network cell reception and puts load on battery.

[sarasphotobox]

I get drain too I don't get it but I partial charge phone I never charge up to 100%