Also some people encounter battery drain problems since the upgrade to A13 (like myself, see FP4 battery life got worse after Android 13 update - #209 by Lars_Hennig ). Can you check the root cause for your battery drain?
Feeling you have been cheated is something nobody will be able to change, but together we could try to find out if the battery drain issues on the FP4 all have something in common or not.
No this battery drain started with the 5th of septemre, the security update.
I’m not willing to root this device again to troubleshoot. (or do some adb magic I do not understand)
Why do you think you have to root the phone? If you use the battery usage from settings you might see the mobile network in the top ranks of apps using up the power. That would at least give a hint leading to the same problem I described in my post.
Good morning,
A few days ago I posted a criticism of Fairphone, specifically about the battery management of the Model 4 and the lack of an Android update.
Last night I received the announcement of the Android 15 update and I installed it immediately.
I haven’t had any problems so far, and the battery drain has clearly returned to normal.
Just as I criticized Fairphone, now it’s only right that I congratulate them on this update, which solved two problems in one fell swoop.
Thank you.
Moin,
Yesterday, I updated to Android 15. The first attempt ended up with a permanent reboot of the phone, but “switching back” to A13 was surprisingly easy and quickly done. Before the next attempt, I changed from Nova-launcher to Quickstep and the update succeeded smoothly. Changing back to Nova then was as easy and everything seems to be working perfectly 
Besides… there’s no change about the energy consumption: it’s still 3-4 % per hour at standby, as it’s been after the last update in September. What a disappointment! 
Cheers,
Thomas
In my case of a Fairphone 4 which used to have an intolerantly fast battery drain even when idle, the latest update to Android 15 seem to have fixed the drain.
So I can now sell a replacement phone I had to get due to this issue…
…and here is what the problem was:
for some strange reason, an additional SIM was added and activated. Before, I only had an O2-eSIM installed. After the update, there appeared another O2-de SIM. This -physically not existing- SIM permanently made the phone trying to find a network, unsuccessfully, which obviously caused 3 to 4 times more energy consumption than usual, draining the battery.
After simply deactivating this additional SIM in the settings, the energy consumption was reduced to normal.
I still face the issue. There is no eSim card installed, I just have a physical one. 80% battery consumption is mobile network, even though I’m at home using WiFi and disabled mobile data (4G/5G). Have to load from 20% to 80% in less than 24 hours.
I already tested various settings, e.g., disabled 5G. Also for some strange reason, the flight mode is stopped after a while without me using the phone at all.
I’m located in the center of a very large city, i.e., a good network availability. Signal strengh is about -103 dBm 37 asu.
I have exactly the described behavior since the upgrade to A13. Nothing really helped solving the issue generically, not a new battery, not a factory reset and not a complete phone replacement.
All these thongs improved the situation slightly but not satisfactory.
I mentioned this long time ago to the support, that IMHO the root cause is a kernel configuration issue. They did not acknowledge that so far
I had this problem a while back and managed to resolve, but just recently it has come back with a vengeance: All of a sudden, I’m needing to charge my FP4 at least 3x per day! Overheating too. This is with minimal use, 5G off, bluetooth off, no apps apparently active in the background, no wifi scanning, not even any mobile data use. Just one physical SIM, no esim. Running Android 15. The only thing I have on is NFC as I use it to scan my blood glucose sensor. AccuBattery app doesn’t show anything unexpected in terms of app drain. I’m stumped!
I would advise using adb to check which process is running wild.
Let us know if you need help with that, or check whether there’s a Fairphone angel nearby who might be able to help. angelsmap
Thanks, if you could point me in the direction to find out how to do an adb check, that would be much appreciated
Read here in the forum:
Official documentation (for reference and additional help):
If using Windows, you may need to install or update drivers (see the guide above).
Linux should work out of the box.
Once you get a reply to
adb devices
use the TOP command, which provides real-time info on current processes:
adb shell top