By default the notification for low battery is at 10%
The critically low notification is at about 3% and the imminent shutdown notification comes immediately after. I find these levels to be too low.
Can they be changed somehow?
According to this answer:
Low and critical battery percentage is now handled by UPower and not by
gsettings (more here). Instead of using gsettings, you should now edit the file
gedit text editor:
sudo gedit /etc/UPower/UPower.conf
Edit the following lines:
UsePercentageForPolicy=true PercentageLow=15 PercentageCritical=10 PercentageAction=8
And the rest changed accordingly.
Only the setting for the action after critical level (line
CriticalPowerAction=HybridSleep) didn't work until I have created a swap space.