Reports of fast battery drain emerges on Samsung Galaxy S3 and Note 2 even if the device is not being used. One of the most noticed drainers is the "Android OS" label on the battery monitor consuming power. So, here are some remedies to reduce or fix battery draining problems for your device.

1. Software Update
Your Galaxy S3 and Note 2 is now upgradable to Android 4.3 Jelly Bean which updates several Galaxy S apps and optimises memory management better. It also includes major bug fixes and everything else needed. Please check first if your variant or network carrier released a stable version before updating the device.

2. Factory Reset
First backup all data files, apps and personal settings before performing factory reset. Go to Settings > Personal > Back up and reset > Factory data reset > Reset device > Delete all. It normally fixes any issue caused by apps and the system that drains battery.

3. Reinstalling Apps
After the factory reset, closely monitor each application you are reinstalling. For every reinstallation, check the battery monitor if something changed to know what app really caused the battery drain. Google apps and services can also be culprits on the battery.

4. Uninstalling Updates
There are system apps which you aren't allowed to uninstall without administrative rights provided by root access. If the culprit app is something like this, uninstall all updates to bring it back on factory version.

5. Disabling Bad Apps
If you are not using certain apps which cannot be removed as well; disable them to prevent them from consuming power. Go to the apps section and select 'All' then manually disable them. All disabled apps are located at the bottom of 'All' tab list.

6. Syncing Configuration
Email, social apps and other similar things are invisibly syncing without your knowledge. Launch these apps and go to their settings then manually set syncing time or set to 'never' to prevent constant refresh of data. In addition, disable the auto-syncing mode to save power.

7. Screen Display
Maximise the Super AMOLED display by using static or live wallpapers with darker colours, reduce brightness level and minimise screen time-out.

8. Wireless Connectivity
Turn off Wi-Fi, GPS, NFC and mobile data not in use to save power. Whether connected or not, active wireless connection always consume battery.

9. Prefer 3G over 4G/LTE
Galaxy S3 as a LTE variant which provides faster mobile data connection than 3G but 4G connectivity consumes higher amount of power than 3G. So if the network coverage is good and 3G data connection works just fine, prefer the network type than 4G.

10. Home Screen Management
Widgets are beautiful especially with animations but 3D widgets and animations are killing your battery. Moreover, most widgets with details are syncing over data that severe battery as well. Minimise the number of home screen panes and only use widgets truly worth displaying.

11. Task Manager
After launching apps and doing everything you need to, launch the Task Manager and kill those apps. Closing these apps will lessen memory usage leading to more juice saved on your battery.

12. Power Saving Tool
For dire and emergency situations, use the Power Saving tool located at the notifications shade to let the device handle battery preservation.

13. Airplane Mode
Turn off the network signal if the coverage is low within your area or whenever you are sleeping without any expected calls or SMS.

14. Android System
A file called "gsiff_daemon" could cause severe battery drain displayed as Android System. It is a non-utilised but highly active GPS sensor daemon that is always on for nothing. Download the ES File Explorer from Play Store > Go to Developer options > Show CPU usage > Look for "gsiff_daemon to pop-up > Launch ES File Explorer > Menu > Settings > Root Settings > Root explorer > Up to root > Mount file system > Go to System > bin folder > rename "gsiff_daemon" to "gsiff_daemon.bak" > Reboot the device.

15. Google Play Services
Some reports of battery drains are caused by Google Play Services and unfortunately, Android devices use the Play Store most of the time. Even if you uninstall the updates, the Play Store will automatic drag it again to your system. The only way to avoid this is to use your device as a phone, music and movie player or picture taking.