"iBattery" is a simplest easiest and yet the most powerful battery charge saving App!
This App saves your battery by disconnecting an Internet connection while in sleep mode.

"iBattery" got more positive reviews in Japan than "JuiceDefender" because it doesn't just disconnect from the Internet but also ends all the running Apps.
Furthermore at a chosen battery level phone can be automatically switched to Flight Mode making you chances of running out of battery even lower. (This feature is available on Android 4.1 and earlier.)

＊Power-saving experiments were conducted on Galaxy S3.

If you phone's coverage is unstable you'll be able to save even more battery power!

â—ŽCautions and other info
・"iBattery" disconnects your phone from the Internet while in sleep mode.

・You can turn it ON-OFF in the Notifications.

・Re-connection speed depends on your device.

・On some devices it is impossible to re-establish Internet connection after screen turns on.

・There are no ads.

â—ŽiBattery introductions by media in Japan.
http://news.livedoor.com/article/detail/8310485/
http://octoba.net/archives/20130906-android-app-ibattery-216139.html
https://androider.jp/official/app/4f0d063537dd7cc6/
http://www.tabroid.jp/app/tools/2013/05/jp.awalker.co.iBattery.html
http://xperia-tm.hatenablog.com/entry/2013/07/07/iBattery-%E3%83%90%E3%83%83%E3%83%86%E3%83%AA%E3%83%BC%E3%81%8C%E4%B8%80%E7%95%AA%E9%95%B7%E6%8C%81%E3%81%A1%E3%81%99%E3%82%8B%E7%AF%80%E9%9B%BB%E3%82%A2%E3%83%97%E3%83%AA
http://ap-land.com/archives/3628
http://weekly.ascii.jp/elem/000/000/162/162275/
http://andronavi.com/2013/04/259313
http://sp.oshiete.goo.ne.jp/app/review/252266
http://androck.jp/app/system/battery_management/ibattery/
http://app-place.net/detail.php?id=jp.awalker.co.iBattery
http://www.gizmodo.jp/2013/05/ibattery.html
http://xenonews.blog50.fc2.com/blog-entry-5487.html
http://s-max.jp/archives/1559152.html
http://www.excite.co.jp/News/android/20130508/Tabroid_app_tools_2013_05_jp_awalker_co_iBattery.html
http://www.excite.co.jp/News/android/20130906/Octoba_216139.html
http://www.lifehacker.jp/2013/05/130514tabroid-republished.html
http://halpost.com/technology/android_application/7208/
http://market.yahoo.co.jp/app/android/details/jp.awalker.co.iBattery/a
http://www.appszoom.com/android_applications/tools/ibattery_gfdzi.html
http://app.dcm-gate.com/app_review/001dmjk/
http://ch.nicovideo.jp/tabroid/blomaga/ar222459
http://appsomm.jp/recommend/2013/10/28/75158/
http://appnavi.sonymobile.co.jp/pc/ag/index.php?page=cate&cid=8&id=2851
http://android.giveapp.jp/RecentReview/index1.html?app_id=jp.awalker.co.iBattery
http://www.ascii.ne.jp/2013/08/16/%E3%83%90%E3%83%83%E3%83%86%E3%83%AA%E3%83%BC%E6%8C%81%E3%81%A1%E3%82%92%E9%A3%9B%E8%BA%8D%E7%9A%84%E3%81%AB%E5%BB%B6%E3%81%B0%E3%81%99android%E3%82%A2%E3%83%97%E3%83%AA%E3%80%81ibattery/
http://zenback.itmedia.co.jp/contents/ap-land.com/archives/3628
http://androijo.jp/%E6%9C%80%E5%A4%A7%EF%BC%96%E5%80%8D%E5%85%85%E9%9B%BB%E9%95%B7%E6%8C%81%E3%81%A1%E3%80%80ibattery-%E3%82%A2%E3%82%A4%E3%83%90%E3%83%83%E3%83%86%E3%83%AA%E3%83%BC/
http://www.meetroid.com/?p=185480
http://news.ameba.jp/20130607-445/
http://androwire.jp/apps/jp.awalker.co.iBattery/%E6%9C%80%E5%A4%A7%EF%BC%96%E5%80%8D%E5%85%85%E9%9B%BB%E9%95%B7%E6%8C%81%E3%81%A1%E3%80%80iBattery%20(%E3%82%A2%E3%82%A4%E3%83%90%E3%83%83%E3%83%86%E3%83%AA%E3%83%BC)/
and many others …