In case this is copied, go to the original site which should be
https://ossadmin.wordpress.com/2011/03/05/gingerbread-heavy-battery-use-android-os-high-utilisation

I’ve been running Gingerbread for a week now, and have a few issues. The worst one so far is the higher battery consumption. On 2.2.1 I used to be able to reach 16 hours on average with moderate usage of 3G data, voicecalls, email, SMS, Latitude running in the background, GPS, WiFi, Sync all enabled. I have always had my screen on the lowest brightness setting to conserve battery there. With Gingerbread, its been slashed to around 7 to 8 hours.

Looking at my battery usage, the process Android OS has been suspiciously high – around 30% or more of my battery use – more than Display, which was a dead giveaway something was wrong. I went through the proceess of removing widgets and apps that created running services. I even switched back from ADW Ex to the default Launcher. Still had Android OS registering high.

I cleared the cache from the boot menu, but still Android OS was still registering high battery use.

I did a bit of Googling, and came across this thread on Android google code site:
http://code.google.com/p/android/issues/detail?id=15057&q=Android%20OS%20gingerbread&colspec=ID%20Type%20Status%20Owner%20Summary%20Stars

The prevailing view is that the WiFi  Sleep Policy is the cause of the high battery drain. It has been suggested that having a sleep policy set to Never when plugged in results in the high Android OS utilization. I have tried switching to Never as the thread suggests, and this has worked for me. I managed to get 16hrs on battery, with 28% left by the end of the day. This morning’s graph shows a very gentle slope compared with my previous ones.

Battery UsageBattery Usage - Graph

I would say its conclusive in my case that changing my WiFi policy to “Never” has fixed the issue.

For those of you having this issue you can change your settings as follows:
Hit the menu button and navigate to Settings->Wireless & Networks -> WiFi Settings


Hit the menu button and select Advanced as shown above.
You’ll see the following screen:

Click Wi-Fi sleep policy and a dialog box appears.


You should see Never when plugged in is currently selected.
Change to Never and you’re done.

You will have to fully charge the phone to clear the battery usage info, but monitor your battery usage and see if this helps your battery usage.

Thanks to the people on the android issues page for their suggestions, and the other sites I have visited.

Thanks also to Aatif for his great post on how to take screenshots of phone using the Android SDK. His post can be found here:
http://www.addictivetips.com/mobile/how-to-take-screenshots-of-android-device/