[AlanHo]

I have a Samsung Galaxy A3 phone loaded with the latest Android update.

I hardly ever use it with data switched on and only rarely is it used on WiFi. It's only purpose is as a phone which again is used very infrequently

For the past year I have recharged it overnight every 2 or 3 days but suddenly the battery is losing power from 100% to 10% in just 12 hours. This without data switched on or any WiFi use.

Today I used the phone for checking my Emails - for about 5 minutes and it has been unused ever since - yet after just 8 hours from unplugging it from the charger the battery is now reading 12%. I have checked all the settings, data, WiFi and Bluetooth are all switched off and there are no Apps loaded.

The same thing happened to my wife's identical phone a few weeks ago but the problem went away after a few days for no known reason.

Ant ideas anyone?

[CraigB]

If no new apps have been installed which may be trying to call home or activated other features like GPS and there is nothing running in the background then the battery could be on it's way out

I guess you've tried a restart...other than that I've got NFI

[asathorny]

If no new apps have been installed which may be trying to call home or activated other features like GPS and there is nothing running in the background then the battery could be on it's way out

I guess you've tried a restart...other than that I've got NFI

Craig took the very words outa my mouth....  I haven't had an Android phone for ages but it's my recolection that the batteries are easy to change.  Do be aware of the so called NEW BATTERY scams.   

[AlanHo]

On most phones the batteries are easy to change - not so with the Galaxy A3. It is glued together with a heat seal membrane and has to be opened with a heat gun, then re-sealed.

I have my doubts that the battery is the problem - only because my wife's phone had a similar problem but it went away mysteriously.  I can only hope mine does the same - if not I will replace the phone with another model.

The problem with that is finding a small smartphone with the features I need. Phones are getting bigger - my pocket is not.

[Shambles]

If you're using Oreo (which I think you hinted at) you can look at the task list and inhibit background processor/data usage on a per-app basis.

[xiziz]

Its not the battery, youre experiencing a classic wakelock, some app is prevention the phone from entering deep sleep/hybernation.

Solution is to either remove the culprit app, or reign it in. Check the battery usage stats what has been draining power. Or Use betterbatterystat to find what is causing the wakelock. Usually Google Play store is the culprit, which we need installed.
Greenify will help your phone hibernate apps when the screen goes out. Thi k this might rewuire root though.

Localisation settings could also be keeping the phone woken.

[The Gonz]

Have you tried watching its drainage while in Airplane mode?

[eye30]

Where is the phone kept?

Is it possible that it has got moisture in it?

Sent from my ATU-L11 using Tapatalk

[AlanHo]

I have solved my battery life problem. Last evening while having a fiddle with the phone I found buried in the bowels of the settings, a battery save option that had become turned off.

Here are the steps

Settings
Device maintenemce
Optimise - let it run to completion
Battery - which gives a choice of battery save OFF or MID or MAX
Mine was OFF - Pressed MID then APPLY
It then carried out the necessary operations.

Today it was 100% when I unplugged it from the charger and is now at 71% 10 hours later.

I have made 2 phone calls today and used the WiFi for about 30 minutes to browse the internet. I also used Bluetooth for about 40 minutes trying to copy my address book to Libby's phone.