Right now you can type "pt-status" in a console window, but there is no continuous battery status display while you are on the desktop.
I have therefore created a little program to display the pi-top battery status on the desktop. It displays a small icon on the task bar.
To download, use the browser and navigate to github.com
Then search in github for pi-top-battery-status
Installation instructions are there.
Questions and suggestions for improvement are most welcome.
Rene I reported this issue about 2 weeks ago with a fully charged battery showing an error message until the power cord was disconnected - it appears to be a binary assumption in the code ie its either charging with time left to full or discharging with time left for use with no logical outcome provided for fully charged. I'd love to know of course...
The battery status program (link above) works well with pi-topOS Polaris.
Scroll towards the bottom and look at the link found in the section "What to do if you have problems with your battery".
Suggestions for improvements of this procedure are most welcome.
The new desktop PIXEL has been released for Raspbian Jessie (not for pi-topOS), see raspberrypi.org/blog/introducing-pixel/
Upgrade instructions to PIXEL are in that blog.
The newest version 1.4 of the pi-top-battery-status is fully compatible with PIXEL, but needs to be reinstalled after upgrading to PIXEL. Instructions for upgrading of the pi-top-battery status are at github.com/rricharz/pi-top-battery-status