Battery power alert level

[Sam Varshavchik]

In gnome2 there was a setting for me to adjust the level where I'd get  
alerted that my battery is running down, as a percentage of battery power or  
minutes left. There was also a similar setting I could adjust for initiating  
a shutdown.

In system settings/power all I see is a single setting to shut down or  
hibernate when I'm "critically low". Where do I get to define what  
"critically low" means, as I could do in gnome2?