I'd like to introduce you guys to an app I wrote for saving battery and data.
It essentially turns off connections like WiFi, Data, and/or Bluetooth when the screen is off and they aren't being used. There are other options, like having the connections turn on periodically to allow for notifications to come in, etc, or to set certain times of day where you do or don't want it active.
It's free but some of the options are unlocked by buying the premium upgrade from within the app. If you'd like to check it out, click the link below to get it from Google Play.
Hopefully it's pretty self explanatory from the screenshot: