I have set UPower.conf to
and through dconf editor sometime ago and it is still there. Notify-osd usually notified at 26%, then at 24%. There’s actually no setting option to change the critical battery level in u-c-c, which is terrible. This is available in XFCE, shown below, (available in my Openbox system)
It would be nice to have something like this in Unity (and in the default Ubuntu, if the guys are looking). Some laptops don’t even have removable batteries these days.
If suspend works when battery is low, (or should it be when the battery is critical,) it’d be nice.
EDIT: the suspend didn’t work at battery low state. It went further down and the laptop went off at 20%.