[Galaxy S II General] PunkOz:
This thread will only contain detailed but simple and easy to understand information and broken english because I'm Mexican and I live in Mexico.

This is my first thread in XDA, this phone is my first smartphone or touchscreen phone I got it a year a go when It came out and this post will have all my knowledge about SGS2 battery saving tips I've got from this year.

Some settings might sound dumb, like why would you disable a core if you paid for two, and why would you want lower brightness if you have a SAMOLED+ screen which is brighter than SAMOLED HD, well those settings are optional and you have to find which ones will help you when you need battery badly for an emergency or something.

First let's make a list of all the apps that you need to use and what they will do, all the apps and tips are optional but if you use all of them you will have some amazing battery life!

*This thread only contains free apps so you don't need to spend $ at all!*

#1 Screen filter: https://play.google.com/store/apps/...ch_result#?t=W251bGwsMSwxLDEsImNvbS5oYXhvciJd

This app is really useful because it allows you to go on lower brightness than what your phone allows you to! and if you have sensitive eyes it'll help at night, when I really NEED BATTERY I lower the brightness as much as I can (Don't go too low because you won't be able to see s**t.

while in use, screen filter make the install button in the package installer unusable; if you want to install an app, disable screen filter first

#2 Rescan Media ROOT: https://play.google.com/store/apps/...SwxLDEsImNvbS5hZGR6Lm1lZGlhc2Nhbm5lcnJvb3QiXQ..

This app will allow you to enable and disable media scanner whenever you want. Media scanner drains ur battery a lot specialy if you're using a JB ROM! I don't know if it'll be useful with GB/ICS because I only tested it on a JB ROM, by disabling media scanner you won't be able to see pictures or videos from your gallery but you're able to play music, use this when you really need to save battery and you're not gonna use gallery.

#3 https://play.google.com/store/apps/...sMSwxLDEsImNvbS5yb290dW5pbnN0YWxsZXIuZnJlZSJd

BE CAREFUL WITH THIS APP! IF YOU'RE NOT SURE OF WHAT YOU'RE DOING ASK AN EXPERIENCED USER OR JUST LEAVE IT!

Titanium backup has an option to uninstall system apps but this one is free, just use it to freeze apps that you don't use and are always running, the apps I disabled are:

*Maps (I enable em when I need them)

*TvOut

*AccuWeather

*Movie Studio

*TalkBack

*Apollo (I use PowerAMP)

*Sound Search

*Voice dialer (Useless IMO..)

*SIM Toolkit (I don't know if this is safe to remove for all users but I had no problem)

*Trebuchet (I use Nova Prime)

*News & Weather

And you can disable other apps that you don't use, those are the ones I disabled.

#4 Startup manager: https://play.google.com/store/apps/...wsMSwxLDEsImltb2JsaWZlLnN0YXJ0dXBtYW5hZ2VyIl0.

This is my favorite, I don't know how useful it is but I hate to have apps I don't use running or on the background.

With this app you can disable the user and systemapps that auto start when you turn on your phone, they will start without any problem when you need them!

This app will give you more free ram! I don't know if the RAM on phones consume as much energy as PC RAM but I used it anyway..

The system apps I disabled are the following:

*Youtube

*Clock

*Email

*Download manager

*Media Storage (I guess you don't need this is you disabled media scanner already with the previous app)

*Gallery

Those are only the system apps, remember to disable YOUR apps that are always running on boot and you don't need them to be running (I only kept facebook, facebook messenger, nova launcher and whatsapp) I don't suggest you to disable many google apps, I think it gives problems when trying to connect to google servers (NOT SURE) disable them if you want and if it give you any problem just enable them again.

#5 FastDormancy Toggle: https://play.google.com/store/apps/...W5tb3JhbC5mYXN0ZG9ybWFuY3l0b2dnbGUuaTkzMDAiXQ..

First do a google search and check if your carrier supports FD, my carrier doesn't support it so I disabled it and you can uninstall this app after disabling it if you want.

#6 AdFree: https://play.google.com/store/apps/...DEsImNvbS5iaWd0aW5jYW4uYW5kcm9pZC5hZGZyZWUiXQ..

This app gets rid of the annoying ads, they consume battery because they use 3G to load and they're annoying anyway, just install it and after it downloads the host files and installs them you can uninstall this app if you want, if you start to get Ads again just install it again and update the host files and uninstall or you just can keep it and let it download the new host files.

#7 GetRIL: https://play.google.com/store/apps/...t=W251bGwsMSwxLDEsImNvbS5zaWJib3IuZ2V0cmlsIl0.

Some users have better batterylife after matching their RIL with the current modem, you can uninstall this app after installing the right RIL but I think the RIL will keep changing everytime you flash a new ROM. This app is supposed to keep you away from RIL crashes, try it. and uninstall after using it.

Ok that's it now let's move to the tips, some of them might have you tired already but I'll put them for the new users.

#1 If you're not gonna browse, use facebook or any app that requieres 3G just disable it, I have 2G most of the time because I only use whatsapp and gtalk the most.

#2 Disable WiFi, GPS, Bluetooth and Sync if you're not using it.

#3 Disable google now (It improves battery a lot according to some users)

#4 If you're lazy to control your brightness just set it automatic, I use the notification bar slide brightness from CM10 and I always have it really low.

#5 Try not to have too many root apps running on start up because SU makes the phone laggy when it tries to enable too many root apps.

#6 If you have a weather app set "refresh manualy"

#7 If for some reason after using all the apps from above you still have unwanted apps running just stop them manualy, I check running apps really often and stop them.

#8 Some people have better battery life with different modems, I always use stock modems so try different modems and check which one suits you better :)

#10 Don't let your phone charging overnight

#11 If you're REALLY need battery and you're on a trip only listening music with the screen off, set your CPU to 200 Mhz or 500 Mhz if you want, Music player is a light app but some music players keep going from 100-200 mhz to 800-1000 ..

#12 Try to enable the skip track with volume key from CM10/AOKP, this will save battery as you won't turn the screen on everytime you want to skip track and If you use the 200 Mhz max frequency you won't have to go through the lag to skip a track (If your galaxy lags a lot at 200 Mhz, some phones don't lag that much at that frequency)

#13 Disable BLN

#14 If you're not using the internet at all put flight mode

#15 Use dark or black wallpapers and themes, our SAMOLED+ Screen saves energy if you use black/dark themes/wallpapers

#16 If you have facebook and you need more battery try to log off your facebook and facebook messenger, it'll save you some battery ;) (credits to Obagleyfreer for this tip)

Now let's get into the ROMs and Kernel subject.

I'm using Dorimanx 7.3 and I'm using JellyBam ROM at the moment but I change ROMs really often, I think JellyBam has vsync enabled so I guess a ROM without vsync and Dorimanx 7.3 will have better batterylife.

ExTweaks settings:

Easy.. Just go to recovery and go into specific kernel options and put Battery profile.. If you have ExTweaks plus you'll be able to change the profiles from the app and you'll see the Extreme_battery profile, enable it if you have ExTweaks plus.

After you set battery profile go to the CPU tab and put second core always off if you're just chatting and listening music you don't need both cores enabled.

Oh yeah and undervolt your CPU/GPU in ExTweaks, I have CPU UV -75.

If you did a charge cycle and your phone is at 100%, unplug it and go to the MISC tab on ExTweaks and Reset Fuel Chip and charge it again to 100%, I usualy reset it like 10 times after flashing a ROM, I unplug and reset and plug and like that a few times.. I'm not sure if it helps at all but I do it anyway.

**I think some users reported that slower charge gives better battery, in ExTweaks MISC tab theres an option for charging voltages, set the lowest AC/MISC:550mA USD:450mA (I haven't tested it but I will do it soon**

I'm adding more info to this thread and giving credits in a few minutes I have to eat dinner.

As I explained I'm from Mexico and this is my first help/guide thread in XDA, If you liked how I shared all my knowledge and want to help me with a donation feel free to do it, I'm from Mexico as some of you know this country is really poor and even 30 cents or 1 USD will help me, 1 USD is like 13 mexican pesos.. feel free to donate if you want, any amount will do fine.

Ok after trying to discharge my phone using Max brightness, both cores enabled, screen on all time, PowerAMP on speakers all the time with max volume, 1.5Ghz, Extreme_Perfomance profile I got 3 hours 30 mins screen time.. I couldn't take a screenshot cause I took too long to take it and I had media disabled :( Now I'm going to try with my settings and post the results! Please if you tried my guide and got amazing battery life post a screenshot of your battery graph and screen on time or tell us the results!