Battery Savers with the Android 4.0 Possible Duplicate:
  What can I do to increase battery life on my Android device?  




How do I save on my battery on my new 4.0 (Ice Cream Sandwich) device? All I have seen so far is a bad battery and no task manager.
Saving battery on devices is very much related to the usage given by the owner. Disabling network connectivity like 3G, closing APPs that aren't being used, adjusting the screen brightness and the screen time out are some of the ways to go.

Personally I do feel that depending on the situation a user will need to have everything available, at a couple of taps distance. So, one APP to control them all is my recommendation.

There are a few APPs at Google Play that help you safe battery life, being my personal favourite:


Easy Battery Saver by 2Easy Team


  Easy Battery Saver is a powerful yet easy to use power manager app specifically designed to extend battery life and optimize using habit.
  
  Easy Battery Saver saves your battery by intelligently dealing with phone’s network connectivity, screen time out and screen brightness. What’s more, the considerable sleep schedule setting will save your battery when you are sleeping.





With this APP you can define usage profiles or use preset ones, and switch between them easily, allowing you to keep your battery consumption at the lowest possible levels for each situation.



Additionally and as already mentioned on the comments, read the community wiki entitled What can I do to increase battery life on my Android device? for a large overview of what can be done on this subject.