[X 2014 General] -Luigi.:
Well guys, thanks to your feedback.

I got to a conclusion:

This is most likely a cronic battery problem, since no methods seems to work permanently. I've seem at least 5 ways of calibrating the battery and fixing this problem of turning off early, and none was a confirmed solution. Some of them may work in the beginning, but the problem returns after a few charging cicles.

I replaced the battery with a new one, and this problem got fixed. So it doesn't have anything to do with the software, its actually a problem with the battery itself.

So, only way to fix this is buying a new battery. :(

Original post:

Well, before anything I would like to say I'm aware there are other posts about this, such as THIS, but the method I'm gonna be describing here is a bit different and didn't find any topic/thread about it, so I wanted to share it.

I have my Moto X 2014 for about 1 year now, and I started facing some problems with the battery. On the last months it started powering off when It reaches between 10 and 20%, without any "Powering off" warning/popup. I didn't try those "Battery Calibration" apps cause from past experiences I know it doesn't quite work.

So I had this method in mind, and until now it worked just fine, the phone is turning off as it should, when it reaches 0%. Also seems to be lasting a bit more. Actually at the 1% it took an eternity to die.

What you will need:

1. Some free time (you need to discharge your phone and then wait it to fully charge powered off)

2. TWRP recovery (or any with a file manager function)

3. Faith

Steps:

1. Discharge your phone until it dies (you can either play some game, or use an app called "Battery Waster". Put the brightness to max and turn on everything (3G/4G, Bluetooth, GPS) to speed it up.

2. Now check if the battery is really empty (mostly probably not) by entering on your TWRP recovery. The battery percentage shows up in the top.

3. The goal now is to uncharge the phone until it dies completely and won't even turn on anymore, no sign of life. You can do that in some ways:

- At the recovery, go to the settings and disable the screen timeout. Then just leave it there until it dies.

- Enter in recovery, reboot to system (normal power up). It should turn on normally... use it until it dies again. Repeat this cicle until you can't turn it on anymore (even to bootloader/recovery).

4. Now its the time to charge it. You need to charge it up to 100% with the phone powered off all the time. You may like to give it some extra minutes after it reaches 100% (just to be sure hahah).

5. After completely charged, plug it off, wait some seconds and enter into recovery mode. You need to go into the File Manager (Advanced > File Manager), navigate into data/system and search for batterystats.bin (there may be also some files related, another .bin and a .xml. I deleted them and got no problem). Select the file and delete it.

6. Turn it on and use it normally as you would. I recommend you let it discharge completely without any midwhile charging. This way you get a full cicle of charging/discharging.

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Worked nice for me, let me know if it works for you too!

I hope it helps someone :)