The macOS Sierra 10.12.2 update removed the ability to see the estimated time remaining, under the menu bar battery icon, on Macs equipped with a battery (various MacBooks). It is no longer possible to restore the functionality.
However, the same information can be obtained in the Activity Monitor app. Launch the Activity Monitor app using one of the following means:
Go to Launchpad → Other folder → Activity Monitor.
In Finder, go to Applications → Utilities → Activity Monitor.
Search for Activity Monitor using Spotlight.
Once the app is launched, go to the Energy tab. The time remaining estimate is shown towards the bottom.