Really I love this phone. It is fast, beautiful, the camera is awesome and MIUI is wonderful. But I don't know why the battery drain is so strange. It is sometimes really good and takes ages until it is empty. My girlfriend has the same Mi2, but uses it always with Power Save Mode. Anyway, the same stuff happens sometimes on her phone. She had it now 16 Hours at home, because don't has a Sim Card right now. It was only connected to WLAN and checked some times Email with Gmail or Facebook. Screen wasn't on, nothing, only lying around. In 16 Hours from 100% to 65%. This isn't bad, but good is something different. Where is the heavy battery drain that uses so much power. I installed Power Panel, CPU Stats, but the phone is often in Deep Sleep, no real App that popups to be a heavy battery consumer. And also my phone. I have to say I had installed 3.1.19, 3.1.25 and 3.2.1, but it doesn't depend on the Rom Version. So I charged my phone and set my clock, 3 different times, activated FLIGHT MODE, and the battery drained from 100% to 75% in 6 hours. Is this normal, NO. And after I activated it the battery drain runs nearly flat. I also noticed this years ago on my S1, on my LG or Defy, with different Miui Versions over year. Don't know if it is the system or the phone, but this happens some times. Does somebody have also noticed that ????