Apple’s OS X Mountain Lion removed the ability for laptop users to see the exact amount of time left on the battery charge in the menubar – which annoys some users to no end. But you can not only get that info back, but add even more with this free app for OS X.
Battery Time Remaining (BTR) is a small app that places a battery indicator in your menubar just like the built-in battery monitor, except it displays the time remaining instead of just a percentage. In addition, you can set BTR to show detailed battery information such as battery cycle count, temperature and power being used. You do so by turning on Advanced Mode in the preferences of the menubar item.
If you like, you can also set BTR to add a system notification to Mac OS X’s Notification Center at specified times in the Notification menu of BTR. I like that you can choose more than one percentage for your notifications, rather than only offering one or two pre-defined settings.
Battery Time Remaining is a free app which can be downloaded from the GitHub page.