Battery Drops to 81%, Only 3% Usage Detected

[AC Question]

Hi everyone,

I performed a Factory Reset on my Samsung Galaxy S7 Edge as all of a sudden I was experiencing poor battery performance. Since the Factory Reset, I now only have the device's default apps installed, with the exception of me installing WhatsApp!

The features turn on are: WiFi, Location, Bluetooth, Mobile Data, Sync, NFC and Always On Display (Night Clock). This has always been the case since day one and I don't really want to start having to disable features as that becomes a nuisance.

Just before going to sleep, I charged my device to 100% and then unplugged it. On checking it this morning, the phone had been on battery for 7 hours 53 minutes (totally unused during this time) and it reports the following: Cell Standby at 2% (53 mAh) and Device Idle at 1% (41 mAh) and that's it.

For the first year, the phone would only drop by say... 3-5% for the whole night (with all my fancy apps installed!)

Why would the performance drop so significantly? How can I fix this? Could the Android OS be doing something in the background that it actually isn't aware of and is eating up my battery?

Any comments and tips would be greatly appreciated.

Kind regards,
X22

 

[belodion]

First, if you charge to 100% and then immediately start using the phone, does it discharge abnormally quickly with normal daytime use? If so, it may simply be that the battery is faulty, so we need to establish that first.

 

[X22MAC]

Hi @belodion, I have not noticed any abnormal discharge of the battery after it has been 100% charged. It just generally tends to go down a lot quicker than in the past. Have there been occurrences of any Android OS that have contain a bug and therefore put a unknown/unexpected drain on the battery?
The current build I have is: Android Version 7.0, Baseband Version: G935FXXU1DQD7, Android Security Patch Level: 1 July 2017.
Much appreciate your assistance,
X22

 

[belodion]

I'm not aware of any current bugs, and if there were anything causing the overnight battery drain, it ought certainly to show in your battery usage stats. If Android OS, for example, topped the list of overnight users, one of the packages included in that would be the cause, and you'd have to work out which one. In your case however, only Cell Standby and Device Idle are showing, and have not consumed excessive amounts. I can only conclude therefore that your battery is probably beginning to fail.
I'll move the thread to the S7e forum for comments from other users.

Also, welcome as a new member.

 

[X22MAC]

@belodion, thanks for your advice.

I have had the phone for less than a year (brand new), would this warrant a full replacement or are batteries generally classed as just consumables that I would have to pay to get replaced?

I have attached some screenshots this time!

Cheers
X22

 

[belodion]

I believe that batteries are warrantied for six months. It might not be that, but I can't see what else it's likely to be.
For what it's worth, I have a Lumia whose battery loses charge, even if removed from the phone. The battery is therefore presumably faulty. As I understand it, the S7e battery is not easily removed, but you could test whether it loses charge when the phone is fully powered off.

 

[Rukbat]

That 2% cell standby isn't 2% of the battery capacity, it's 2% of the 81% of capacity used. IOW, the battery is 3600mAh. 81% of that is 2916mAh. so 684mAh has been used. Of that, 2%, or 13,68mAh was used by the cell radios in standby.

Other things are running, though - Android System, Android OS, Device Idle, and other things used by the system (that are evidently hidden in the new updates). Using 19% of the battery in 8 hours means (according to the advertising numbers, which you should never do - recharge at 40%-50%, not at 0%, as the advertising numbers assume) about 5 days of normal standby (most people turn their phones on when going to work and turn them off when they get home).

The better they make the system, the more software they add to it, and that shortens the battery life. (And we all remember what happened with the larger battery in the Note 7, so they keep it small.) You can't get increased performance and increased battery life, using the same capacity battery in a small (and especially airtight) case.

BTW, if you unplug the charger the moment it gets to 100%, the battery is only charged to about 95%-98% (depending on the battery). Leave the charger plugged in for at least 15 minutes after it reaches "100%".

 

[Golfdriver97]

Welcome to the forums. How long ago did you do the reset?

 

[X22MAC]

Thank you all for your responses so far.

@belodion - I haven't noticed any drop in battery when the phone is turned off.

@Rukbat - Quite in-depth information on how Android calculates battery usage. Have you experienced these issues from an OTA Android Update? If so, have you reverted back to an older installation? If so... how?!

@@Golfdriver97 - I performed a Factory Reset two days ago and the phone has been restarted a couple of times since.

So......
Another night and another test with WiFi, Location, Bluetooth, Sync and NFC all turned off.
In addition to this I also wiped the Cache Partition in Android Recover Mode, as there were some suggestions that this would fix the issue.

Attached are screenshots of the results and it's safe to say that there has been no noticeable difference, compared to the first night. Gutted!

So, I have been offered a repair, yet it could take up to 28 DAYS! I am not even convinced that they will see the issue first time around and the phone will be sent back and forth for repair. Are companies under an obligation to provide a temporary replacement? I.e. I didn't purchase a phone and not expect to have it in my pocket. If I bought a car and there was a fault, I would expect a courtesy car whilst mine is being repaired....

Cheers,
X22

 

[Golfdriver97]

Sometimes a reset is like turning the phone on for the first time. The OS and the kernel do a lot of background processes that look like a battery drain. I would wait a couple more days...it might settle down.