[Galaxy S II General] asti009asti:
Hi Guys,

I have read this thread and a couple of other threads on XDA and other forums dedicated to Android OS process.

I have summarized all the tips given and applied to my phone. The battery life has improved significantly:

1. I am on XWKDD, rooted, did a factory data reset.

2. Installed Titanium back up (free version).

3. I have done a back up of the following apps and uninstalled them (as I don't use them). The mandatory ones for removal are marked in bold as many people were saying there is a proven problem with those which causes battery drain. The rest are optional but I have noticed some of them are running services in the background and therefore have removed them as well. You are free to leave them installed:

-BBC iPlayer

-News & Weather

-Came Hub

-Samsung Account

-Music Hub

-Suggests

-Wifi Sharing manager

-Wifi sharing

-Mini diary

-Readers Hub

-Samsung Apps

-Social Hub

-Ap Mobile

-Buddies now

-Days

-Digital clock

-Email

-Yahoo! Finance

-Social Hub

-Software update

2. I opened Settings and switched to Accounts and Sync and left background data checkbox checked while I have unnchecked auto-sync. For me there is no reason for an application to sync in the background if I don't open it. Once opened you can easily force the sync manually and it will work perfectly well. Unchecking this option helps you to avoid syncronization in the background when in sleep or awake mode which eats your battery.

3. I have set a wifi sleep policy to Never in Settings >> Wireless and network >> Wifi settings >> Advanced >> Wifi.

4. I have enabled power saving mode (settings >> Power saving mode) to turn off wifi, bluetooth, GPS and Sync when I don't use them. Just set all 4 checkboxes and you are safe.

5. You then need to calibrate your battery. Here's a step by step guide on how to do this:

Battery Calibration (not needed if you flashed with 100% battery and let it deplete/recharge fully 2 or 3 times)

Sometimes the battery isn't being used to its full extent, or it shows wrong values. This is due to some wrong data stored in a file called batterystats.bin stored in /data/system. The steps below will show you how to stretch the battery use and delete the file inCWM (ClockWorkMod) in order to start with a full battery and fresh stats.

- Charge your battery full, bump charge to get the highest level possible (not a big deal if it shows 97% when you unplug after bump-charging),

- Drain your battery to 0% until it shuts down by itself (without plugging the charger or connecting the phone to a pc),

- Wait 2 minutes and reboot the phone to ensure the battery is completely flat (it might reboot fully, half way, not at all, don't worry) until it dies again,

- Remove the battery and wait 2 minutes,

- Replace the battery and plug the phone to the charger without switching it on until it shows 100%,

- When phone shows 100%, boot in recovery (volume up + home + power) and go to > Advanced > Wipe Battery Stats > Confirm (move up/down using the volume keys),

- Reboot the phone and unplug the charger when the "battery full notification" comes,

- Now use your phone until the battery is flat again and charge full (no need to have it turned off). Repeat 2 or 3 times and your battery will be calibrated,

- Only wipe battery stats once, run a few cycles of full charge / discharge and after that just use your phone as normal (i.e. no need to deplete / charge fully anymore).

6. There will be another battery drain problem fix from samsung related to dual core CPU support and wifi in 2.3.4. The later is at the rumours level.

that's it. Use your phone as normal, no need to switch off everything - just enjoy your device. You will be impressed how seriously your battery life is improved.

Hope this helps.