I removed the battery icon from the toolbar. How do I add it back?

Here are the links to the screenshots: https://www.dropbox.com/s/m6nhxv403s4717o/Screenshot%202014-12-28%2000.10.45.png?dl=0 https://www.dropbox.com/s/wpmccaacmnzjqv1/Screenshot%202014-12-28%2000.10.24.png?dl=0

As you can see the battery icon is missing because I accidentally removed it by CMD+Click+Dragging it off of the toolbar. Also, the customize toolbar button is not clickable.