[Xperia Z5 General] millicent:
If you're looking here you might be struggling with terrible battery life after the mm update. The first couple of days and few complete cycles after my update, I was getting less than 3 hours sot, in less than 12 hours, whereas lollipop treated me much better, approximately 5-6 hours sot in 24 hours. Let me clear some things from the very start: I am not attempting to create perfect battery life by sacrificing radio speed, disabling wifi when asleep etc. I'd rather have lte whenever possible and I only stop the radios at night between 11pm and 6am, using the tasker-like app included with z5.

I will continue by explaining a little bit more thorough how I did my update and in next post will give the exact steps to follow so if you're in a hurry or only here to find tips on improving battery life, head there right away. Also, if anyone has other ideas on how to improve on battery life, don't be shy and chip in.

So, since this is my first unrooted android phone ever, I had to adjust a little bit. Where previously I was using a combination of apps such as tasker, secure settings, greeenify, logcat and BBS to diagnose wakelocks and the like, I found that when I first tried to improve on lollipop battery life with these tools, actually I worseend the battery situation. For instance greenify would stop apps so they would take more cpu cycles to start again, etc. The z5, as it is, it has awesome right from the shelf standby capabilities so I feel root for those reasons only is not that sought for, after all.

Marshmallow update

I installed the nordic combined fw with clean wipe of all options present in flashtool. Afterwards I started the phone and let it restore the apps via google backup. At this step you might want to get rid of unnecessary apps (I had quite a few of them). I let all the updates happen, then I headed back to the pc and sony pcc to restore my backup (I know some people recommend starting fresh with the apps but I am the kind of lazy person, and really spoiled by titanium backup, but well, since i cannot have the latter..). I specifically chose to restore the apps data.

After restore it might take a while for the phone and whatever apps you have to sync with their respective cloud and data. I would only mention that although I kept google photos for now (with no auto sync yet) I am rather using the sony memories cloud, it seems to me faster and more standby and mediaserver friendly. So I had some problems with photos but will try it again, maybe it works better in mm.

I haven't disabled a lot of the bloatware, actually I advise you to go slowly and carefully about that since in lollipop disabling some of the preinstalled apps result in random reboots.

What I did though, after the first (horrible) battery cycle was to clear all app cache: settings/storage/internal storage/cached data

I also disabled location scanning under settings/location menu

I also performed a battery re-calibration which you should do anyways once a month or so by letting the device deplete completely (1-2% really) shutdown, charge in the wall charger up to 100%, start it plugged in charger and verify that battery percentage reads 100%, then unplug.

I didn't take a screenshot of the 3 hours sot I got a few days ago, but here are some screenshots of the much improved battery life, second day of 6+ hours. Let me tell you I didn't go easy on the battery either: few hours of listening to flac from ext sdcard in poweramp or google play over apt-x bt, couple minutes of hangouts, few sms, lots of tapatalk/reddit, a bit of camera, in other words, kept radio lte almost the whole day (while at work), all with adaptive brightness at halfway mark