Here are some good tips on how to help conserve battery life for the Samsung Galaxy SII. http://support.sprint.com/support/tutorial/Conserve_Battery_Life_Samsung_Galaxy_STM_ll_Epic_4G_Touch...
This should help in most cases.
Android OS is just short for Android Operating System, which is used for your phone to function at all, in order for your phone to pull up all its graphics, in order for your phone to pull up its apps and open those files to display apps or your internet web pages, to pull up your messages to pull up the function to make calls all are because of your operating system which is constantly running and will be the one thing take up the most battery, can not be removed...unless you want your phone to crash.
not to mention the more you use your phone and are playing with it, pulling up different things on your phone, looking through settings the android OS will be higher, not to mention your OS still is going when your phone is in sleep mode, unless the phone is OFF the OS is processing and using battery
That's the title given to all background tasks in the operating system. You can try a factory reset to see if that fixes the problem. I know some of the Over-The-Air updates messed up my phone temporarily. The Galaxy S2 also malfunctions in weak signal areas. There's unfortunately no fix for that. Hardware reverse engineering has shown that a defective design causes RF signals to bleed into other circuits, like those of the soft screen button controller, when the 3G transmitter is at high power. Some symptoms are high battery drain, random button presses, dead buttons, and reboots. Get rid of the phone if it's still in the return period.
Apparently, there is a new solution to the problem you are referencing, KMcMurtrie; see this post: http://community.sprint.com/baw/message/530293#530293
You might want to print out the appropriate entires and take them with your phone when trying to get it repaired.
Pagette, your battery issue very well could be related to the problem addressed in the above post. I am assuming you are looking at your Battery Usage statistics and seeing Android OS at the top of the list, using up something like 65% or of your battery; correct?
This the actual software that operates your phone, and under normal cicumstances, the Android OS should be at the top. There are some things you can do to conserve battery:
If you are not using a Bluetooth device with your phone, turn it off.
Same with wifi.
... and GPS.
If you live in an area that is not served by 4G (wimax), then turn off 4G.
All the above can be enabled or disabled by pulling down the top information bar and tapping the appropriate button.
Also, you could go into Settings and bring the brightness of your screen down-- the dimmer the backlighting, the less power you will consume.
Surfing the internet and texting excessively (basically, moving data on and off the phone) will contribute to battery drain as well as spending a lot of time in low-signal areas. If your home is in a low-signal area, then you could try to convince Sprint to give you a signal booster or hotspot for the home, and that would probably help improve your battery life.
I live and work in low-signal areas and have to plug my phone in every night. If I spend any time using the internet on my phone, then I will have to plug in and recharge before I head home at the end of the day-- it's an unfortunate fact of life that our cell phones are much less phones now and more like ultra-portable computers, and the more we use tham as such, the more often we will have to charge them.
If you feel that your battery has a really bed life, then you might consider buying a replacement. I would recommend getting a Samsung-branded replacement, as some of the off-brands are unreliable and would only make matters worse for you.