[Nexus 6P General] Paquinho:
Hi people, nexus 6P owner since 2 years now. I remember when I received the phone I could reach without worries 5 to 6 hours of Screen but then, after nougat and now Oreo, I've never achieved again that numbers.

After rooting my phone, flashing carbon rom and installing elemental X kernel, I played with governor profiles and improved my SOT a little over this year but it was getting worser and worser by every day (2 to 3 hours of screen on time and heavy idle drain). Finally, the real problem came the other day when for the first time my phone shutdown at 29% suddenly after opening the camera.

So I read internet and found in the nexus 6 (not 6P) forums that someone suggested a solution concerning a problem with how the phone meter the battery remaining, suggesting doing a series of steps of charge discharge that I will list here. This, and changing to ABC rom may have done the trick, as now I'm getting much more normal battery life (considering the degradation of 2 years, 2700mah left approximately) of 4, 4 and a half hours (yours will be better) SoT and an idle drain of less than 0,5% per hour, and apparently it didn't shutdown early anymore.

So, give this steps a try if you tried everything like I did and you still having problems with battery drain.

STEPS THAT MAY SOLVE EARLY SHUTDOWN PROBLEM:

- Charge your phone to 100% and use it until it shutdowns (look at what percentage).

- Boot to recovery by pressing power and vol - button, and once in there let it drain the battery until it shutdowns by itself (may take a lot of time so increase brightness to maximum in the recovery menu under settings to consume it faster).

- Now it has really reached 0% and if you try to power it on it won't let you by blinking red in the notification led.

- Plug the charger and leave the phone off until the battery indicator show it's full.

- Unplug it and turn it on, it should show you the battery at less than 100%, like 95%, 90% or even less depending on how bad it was calibrated (mine showed 95%).

- Plug it to the charger without turning it off until reaching 100% and only then unplug it first and then turn it off quickly.

- Plug it one more time (off) until the icon shows it is full and then unplug it and turn it on, now it should say a number closer than before, like 98% or 99% (mine was 99) or it may be 100%. If it shows 100% then you're good to go with the calibration, but if it shows less, repeat the process by letting charge until 100 and then doing the same steps as before until you turn it on without charging and finally it shows 100% battery.

Please report back if this steps worked for you, because for me I think it made the trick.

Now for the battery drain what I did was this steps,

STEPS THAT MAY STOP THE POST-NOUGAT HEAVY BATTERY DRAIN (android OS drain, etc):

-Unlock and Root the phone

- Install ABC rom (check the post here in XDA)

- Flash ElementalX kernel (also here)

- Install the app "ex kernel manager" from the play store

- Enter settings and disable printers (you still can enable them if you have to print something)

- Install Greenify from the play store and select all the apps that don't use notifications.

- Uninstall unnecessary apps that you don't use anymore.

- In the Ex Kernel manager app go to CPU -> governor options and select "load". Choose one of the following recommended profiles: Excalibur V2, Dragon Fly v1, Butterfly or DeadPool. (Or check the guide in XDA about governor profiles).

- Finally activate the run on boot option and reboot to recovery, wipe dalvik and cache and then boot into system.

If you have luck like me, your phone will run very smooth and battery life will be normal to it's current degradation. My phone now last me all day like before and I don't have to charge it twice or three times like I did and best of all, when I don't use it, it almost don't lose battery (2 to 3% overnight).

Also I've never seen again that android system process consuming the same amount as the screen!

I hope this serve someone and maybe save some phones too :), I never resigned my 6p because it's a great phone with one of the best cameras out there even today and with great speakers too.

Please let me know if it worked for you! Of course I don't promise it will, but you have nothing to lose anyway! Good luck.

Pd. Sorry for my English , I'm from Argentina :)

UPDATE: Today my nexus shutdown at 10% but only because I opened on purpose the camera to check if that is the problem, and aparently it is. I've read that when then phone has low power, an app that consumes a lot of battery like the camera may cause shutdown to prevent the phone damaging internal components. So no fix for that at the moment, just don't use the camera with low percentage.