Comment 4 for bug 811769

Javier, there is still a gsettings key to configure when the power icon should be shown. And this bug is that indicator-power should follow that setting.

In Ubuntu right now, it is set to hide when fully charged. You are correct that the GNOME default is to always show when there is a battery. As far as I can tell from the changelog, we've been overriding this default for over 5 years.