Retina MBP - "time remaining" not available on menu-bar battery icon?
Battery Time Remaining is a github-hosted, open source project that aims to solve this problem. From the project page:


  Battery Time Remaining
  
  Show the estimated battery time remaining on top of your screen in Mac OS X 10.8 Mountain Lion.
  
  Why does this project exist?
  
  Apple removed the option to show the battery time remaining in the statusbar since the Mountain Lion release. This App will do exactly that, show the battery time remaining on top of your screen.
  
  How do I install it?
  
  Two options:
  
  
  Download latest version, unzip and run the App
  Download the source here from Github and compile it with XCode