[Xperia Z Q&A, Help & Troubleshooting] schaggo:
Top and foremost: search the forums for Better Battery Stats, there's a free xda version in the forums. Install it, let it runf gor a couple days and then post any findings you can get from it. Whining without Better Battery Stats means fingers will be pointed at you and you will be laughed at.

some basic website browsing - What is basic website browsing? Whatever you meant by it, I'm fairly sure it involves lot's of scrolling and lot's of data to fetch, process and display, fast changing display contents, putting a nice steady load on the CPU and communication circuits.

watching half an hour video - no. 2 battery eater, topped only by 3D gaming. Probably even topping 3D gaming when high bitrate FullHD content.

what the hell is mediaserver - gets inherited when producing audio (and video?) output; be it music but also keyboard press feedback sounds, touch feedback sounds, dialer tones and weirdly also touch feedback vibrations. Disable all this, reduce mediaserver %.

brightness heavily impacts the battery - a forum user made measurements, screen brightness had a major impact on mA consumed. This is fully correct.

videos (...) bit-rate and format will have an impact on the battery - again 100% correct. Major impact possible.

I've read that a corrupt file can send mediaserver into an infinite loop - you're confusing mediascanner and mediaserver. So no.

Media server will show up when your watching videos/listening to music - Yes.

when i insert an sd card of some other mobile the xperia z doesnt update its files - as those cards are probably full of junk from the other phone, the mediascanner has to go through all that **** and probably stalls at some point.

need to sort out this media server problem - as per above, disable keyboard vibration and sounds, disable touch vibration and sounds, disable dialer sounds.

how to soft reset the z - http://bit.ly/10CHCw4

turn off all apps,wifi,network data,and location off - this is ridiculous.

i haven't white-listed a single app in stamina mode - can imagine this not helping the cause: you turn on the display, the/a data connection comes back up, all sort's of services go crazy trying to reconnect and re-sync, resulting in a massive power usage spike. Don't know, only think so, does makes sense in my head. Also would mean prolonged periods of wakeloks after display off since all processes are locking the device in awake state till the syncs are complete.

Just to chime in, you need to understand what's going on in your Android system and you can hit the mark on battery life. - Thank you sir, hero post of the day.

Android system is taking up 18% - Batter Battery Stats is the answer to decypher this figure.

i primarily use my phone to watch videos and browse the internet - see above, energy suckers.

the scanning of new folders containing media only happens when you re boot the phone - wrong.

Anyone else use LightFlow and had problems like mine - yes, ever googled for "LightFlow wakelock"? Predestined app to cause wakelocks and standby issues, as the phone needs to wake up to enable the app to control the LED. LightFlow cannot work while the phone sleeps, it's a third party, add-on app.

how to stop facebook push notifications - FB > settings > notifications; FB > Settings > Polling intervall (?): never.

media server *snip* constantly running *snip* manual sync app *snip* scan and then stop - no, confusion of mediascanner and mediaserver. Read further up.

android system is using more battery than it should - Again. Better Battery Stats for a couple days.

media server, this is used for indexing and playing media - No, scanner != server.

Android OS is the UI layer/OS interactions and system is more low level stuff - Android System is the actual system and it's processes and wakelocks including kernel wakelocks. Have a guess... yes, you nailed it: Better Battery Stats.

Maybe I should invest in betterbatterystats - Free forum version available. Search is your friend.

??????? - ???!!! @@@###++++ ????!!!

Im having problems with stamina mode - **** the time estimate display. Useless, graphical gimmick to either make you happy or annoy you and make you pose questions like that.

I've turned off BE - *snip* extra battery sucking - not really, see the aforementioned thread where a user made measurements with/without BE.

using a task killer - a Google Android engineer reading this, will shoot you between the eye. Since ICS (Android 4.0) task managers/task killers HURT the system and battery life much to very much. Do your research.

Next time I'll try getting a screencap - is worthless, get Better Battery Stats.

Howgh.