What can cause "Android OS" process to use high percentage of battery? I've read a bunch of forum posts about the Android OS battery drain bug. This is where the 'Android OS' process is showing large percentages in the battery statistics.

For me, I'm running 2.3 Gingerbread. I don't use bluetooth or GPS. I'm on 2G most of the time. Some days I get 40 hours out of a battery. On these days in the battery usage settings, the 'Android OS' process uses about 3% of battery. However other days I get about 8 hours with similar use. On these days the 'Android OS' process uses about 35% of the battery. I really want to find out what causes this.

The fixes suggested so far are:


Reboot (Temporary).
Turn off and remove battery for a couple of minutes.
Reset battery stats.
Change WIFI sleep policy.
Use a task manager
Flash stuff to the phone.
Revert to older versions of the OS (not really a fix).


Does anyone know the definitive cause of this problem and the correct fix? Or is it possible there are multiple issues that cause this so different things will work for different people?

Here are some of the threads:


FIX and INVESTIGATION: Android OS (battery drain) problem on Gingerbread
Fix- Battery drain 2.3.3 - high android OS
S2 Battery Drain Problem - solved for now
Issue 16721:     Android OS 2.3.3 Battery Drain
I believe, there is at least one bug related to "Android OS" and battery drain. I'll outline how to reproduce the issue: (Tested with Motorola Flipout, Blur_Version.0.28.9_MB511.Retail.en.DE (stock ROM the phone was sold with), Android 2.1.)


Start with a fully charged phone.
Download the Audiobooks (free) app and launch it.
Choose a book from the free library and listen.
Send Audiobooks to the background, e.g. by clicking home button.
Go back to the Audiobooks app by the same operation you used to start it, e.g. click the icon in the app drawer. (This is the only way I am aware of to get the app in the foreground again.)
Do whatever it takes to stop the audiobook playback. (There is a "shutdown player" button, but I never get to use it, because the player just stops/disappears before I can navigate to the player screen.)
Leave the phone idle. After 8 hours the battery will be almost flat (&lt;15%). Android's battery usage monitor attributes 33% of the batter consumption to "Android OS". The remainder is split between "cell standby", "phone idle".
Shut down the phone. Switch it on. Recharge.
Leave phone idle.
After 8 hours, check the battery status (>50%). "Android OS" does not show up as draining battery.


Whether this is a bug in the Audiobooks player or Android or both is not clear. However, this does not appear to be normal behaviour.