The GNOME default of 'hibernate' or suspend-to-disk on very low battery power isn't optimal for many laptops -- hibernate is known to be broken on several hardware setups, it frequently results in file system corruption, and just causes pain. That, combined with the weird behaviour of the GNOME power manager to put the system in hibernate, even when the battery isn't low, annoyed me enough to go hunting for a way to change the default.
The GUI doesn't expose a 'sleep' setting; it just offers hibernate and shutdown, so here's a tip to just put the system to sleep state (suspend to RAM), which is a much well-behaved default for me.
Install dconf-editor, and go to
and modify the
For the curious, the weird behaviour of the GNOME power manager I mentioned above is noted in these bug reports:
Bug 673220 - 'Critical capacity' warning on laptop with multiple batteries broken
Bug 673221 - Shutdown action on battery low doesn't save session
Bug 673222 - More prominent warning, at least 5-10% before battery goes critically low
Bug 673223 - System enters shutdown/hibernate even when power connected but battery low