There is no way some of us are going to lose our Jailbreak, and waiting for Apple to fix its pathetic code on battery issues is not an option - iOS 5.xx is here, we got it, we like it, so lets move ahead...
I've worked on my own iPhone which was great with iOS 4.xx and upgrading to 5.0.1 brought with it Absinthe JB AND Apple's battery woes.
After weeks of research & testing i've come to improve my battery life from 5 hrs to 1.5 days with normal usage
No hearsay - see the proof & fix your own woes...
A WORD OF CAUTION
Backup everything from your iPhone - I always like to start with a clean slate - no leftovers to come haunt us again.
Make a note of all the Apps you had installed as well as Cydia packages as your going to start fresh
You can use alternatives to install/restore them if you have the know-how
1) Download the iOS 5.0.1 (can be JB untethered as of today) or 5.1 (only tethered JB as of today) ipsw file from Apple servers to your computer
2) Connect to iTunes and do a Restore (Shift+Restore if your using Windows)
3) Once done, make sure to Setup your iPhone as New Phone (we don't want any of the old corrupted stuff coming back to kill our battery)
After installing the new OS be sure to also go to (Settings/Reset/Reset all settings)
Standby drain becomes around 2% per hour max after this is done
Battery calibration - Use the iPhone until your battery completely dies (not even 1%).
Now once it shuts down give it a full recharge.
Setting up your iPhone settings (Non-Jailbroken device)
First of all Make sure you reset all Usage settings and enable iPhone Battery %age so you can keep track of the improvements
1)Go to Settings - General - Restrictions (you may need to enter your passcode here)
Now turn PING off
2) Settings - General Location Services
See what I have kept active, or else simply put the entire Location Services OFF
3) Settings - General - Notifications
Make sure u set it to Manual and only keep what apps you want notified about on
4) Settings - Mail,Contacts,Calender - Fetch New Data - Push (OFF) & Fetch(Manually)
You can still download email Manually as this is a huge battery killer!
5)Settings -iPod -EQ(Off)
6) Set Brightness levels to as low as your comfortable and activate "Auto-Brightness"
7) Wi-Fi, 3G, Data, Bluetooth etc. (Keep off when not in use)
Install an app like SYSTEM (or similar) to keep your iPhone RAM free of apps running in the background
They may not be in use, but they certainly do drain your battery by just hanging around!
STEP 6 (The steps from here on are only for Jailbroken Devices)
Go to CYDIA - PACKAGES and remove packages you don't need or can live without
Most of them like AERO, Winterboard, 3DBoard, FlipBoard, and so forth that affect the SpringBoard just eat your battery, so what you can live without - REMOVE!
Jailbroken device please make sure you have the following Repo's added
In CYDIA - go to MANAGE - SOURCES - ADD
Now search and install the following from the repo's I have written beside it)
1) Battery Fix iOS5 (IHR repo) (whether it works or not, why disregard something that may help)
2) Lang2ez (insanelyi repo) (deletes all languages except English from your iPhone - makes it faster)
3) Daemon Tool iOS5 (xtoyou repo) (we need this to disable iOS Daemons that screw with your battery life)
4) MobileTerminal (xSellize) (this is to activate Daemon Tool to do it's job)
5) SBSettings (BigBoss) (this is absolutely fabulous to disable stuff rather than using iPhone's SETTINGS)
I won't detail much here as the CYDIA packages will do the job for you in Auto mode.
However to disable un-necessary Daemons you need to do a bit of work (this process is a HUGE battery saver!)
Start the app with the black icon named "TERMINAL"
Now just follow my screenshot and type exactly as I have on it (in Terminal)
Now reboot your iPhone and give it a full charge, reset usage and smile at the results of your work :)
1) To keep your iPhone in top gear, make sure to keep refreshing its RAM (using the app names "System"), by doing a Respring, or simply rebooting (slowest)
2) Also make sure to keep closing open apps to keep the memory and battery hog's at bay! (see Screenshot)
3) When you don't need things like Bluetooth, 3G, Data, Wi-Fi, Location Services... switch them off!
Not only will your iPhone boot faster, it will run faster & also last way longer!
You've paid a lot to Apple's bad engineers... instead please support people like us (specially Pod2G for his work on JB 5.0.1 with Absinthe) who really do try to make things better :)
IF YOU APPRECIATE MY EFFORTS AND HAVE BENEFITED BY MY WORK PLEASE DO HELP SUPPORT ME TO CONTINUE HACKING/TWEAKING
IF YOU CAN AFFORD TO THEN PLEASE DONATE TO MY BY PAYPAL (email@example.com)
IF YOU CAN'T THEN PLEASE CLICK A FEW AD'S ON MY BLOG SO GOOGLE DOES :)