[Galaxy Grand 2 General] coolvij:
This is the best written tips on battery saving I've ever found.﻿☺😊😄😉

Battery Saving Tips

1. Keeping mobile data (i.e., 4G or 3G) or wifi on all of the time uses battery. Ask yourself if you really need to be notified in real time about every new email, Facebook post, or tweet. If it isn't that important, then keep mobile data and wifi off until you really need it. Although most devices make it easy to toggle wifi off and on, it's a little more inconvenient to toggle mobile data with the stock controls. I like Power Toggles, which is very customizable and easy to use; another popular choice is Widgetsoid.

2. The biggest power drain is usually from the screen. The longer it's on and the brighter it is, the faster your battery drains. Adjust your screen timeout so that it turns off after 30-60 seconds of idle. Turn the brightness down to 50% or less, which is usually more than enough for indoor lighting. Automatic brightness may or may not help save battery--some think that constant sensing and screen adjustment may actually contribute to battery use.

3. Many apps (e.g., Facebook) by default will try to refresh their data on the web at certain intervals. In order to do so, they have to partially wake the device up from sleep, then try to access the web, and then refresh data, all of which uses battery. If you don't need realtime updates, you can typically change to manual refresh in the app's Settings, which prevents the app from waking up the device. For Facebook, all you need to do when you open the app is just swipe down, and your newsfeed will manually refresh to what's current.

4. Google Currents is notorious for being a memory and battery hog. Many people have reported that battery life improved significantly after changing its refresh setting to manual and/or disabling Google Currents completely. (Update 7/2014: Google Currents has since been replaced by Google Play Newsstand, which manages memory much more efficiently, without the same battery drain.)

5. Along the same lines, consider turning off the device's Background Sync. You can find the switch to turn it on or off under Settings/Accounts/Google, but it's easier to use the stock Power Control toggle or the better Power Toggles or Widgetsoid apps. Turning off Background Sync means the device is spending less time and energy syncing your Google account. If Background Sync is off, you can always manually refresh any of the Google apps within their respective menus.

6. Some apps partially wake a device up from sleep (called a "wake lock") numerous times a day to do things like trying to check the web for data updates as well as reporting location data. Install an app to detect wake locks like Wake Lock Detector. Let it run for the better part of a day, then open it and find out what apps are responsible for the most wake locks. (Update 7/2014: KitKat no longer allows apps like this to report wakelocks unless your rooted.)

7. #6 is how I discovered that Google Maps was burning up a fair amount of battery due to its Location Reporting (previously for Latitude, now used for Google+). If Location Reporting is turned on, then Maps causes very frequent wake locks to check location and report it. I don't think Latitude was that popular--I certainly didn't use it, because I don't really want other people to know exactly where I am, so I turn off Location Reporting by opening Maps, tapping Settings/Google Location Settings, and turning off Location Reporting. Note that this does not affect the ability of your apps to use your location to refine searches, for example.

8. Widgets are definitely a cool feature that makes Android unique, but some of them also contribute to battery drain--specifically the ones that need to access the web to update their information (think weather widgets). Review your widget use and remove the ones you really don't use.