mobile

Hi all, I have a problem with the phone i gifted to my GF. Her LG G2 during the night (only the night!) drains a lot of battery, sometimes even 60 or 70%. This happens both with KitKat and Lollipop, with wifi on or off, with airplane mode on or off. I tried even to reset the phone and install just 2 or 3 popular apps. I sent it to LG support and they changed the battery and the radio but the problem is still here. So I tried to root the phone and I installed setcpu to limit the cpu when the screen is off, and with this method the battery consumption is only of 8-10% (not perfect, but at least better).
So, if I ask LG to change the chipset they will do this? Anybody had the same problem? How the hell is possible that this happens only during the night?
Thanks.

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