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This happens to me more than I'd like to admit, but sometimes I don't notice the power getting low since it only shows up in my status bar, then the computer just quits. I'd like a big alert that warns me before this happens. Is there any way for it to alert me? Ubuntu has a nice popup that tells you it's getting low.

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Configure the power-manager from your desktop environment to do "something" - this can usually range from "nothing", over "run a command", to "hibernate"/"power off". –  peterph Jan 9 '13 at 19:33
Which desktop environment? –  Renan Jan 10 '13 at 0:17
@peterph I only have the "Power off" and "Hibernate" options. –  Travis R Jan 10 '13 at 2:22
@Renan running Cinnamon. –  Travis R Jan 10 '13 at 2:23
@TravisR sorry, I meant to say configure the behaviour when critical battery level is reached –  peterph Jan 10 '13 at 8:33

6 Answers 6

write a script!

battery_level=`acpi -b | grep -P -o '[0-9]+(?=%)'`
if [ $battery_level -le 10 ]
    notify-send "Battery low" "Battery level is ${battery_level}%!"

then cron it to run every few minutes or so. But yeah, if you can do it through the GUI, that's probably a much better way of doing it.

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I had that same problem and I figured out a workaround. I installed from Linux Mint repositories an app called GKrellM. It monitors lots of stuff on your machine and there is battery. Setup with alarms, it works for me like a charm.

more info at:


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As I don't have Gnome Shell or Cinnamon installed, I cannot be of direct help as accessing the source could would be much practical since it's rather easy adding such a rudimentary extension with JavaScript.

You should open :


and search for percentageText - subsequently, you ought to be able to add a pop-up message or alert.

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Interesting, didn't know this stuff is in javascript. But no /status directory and no power.js I can find anywhere in the /cinnamon/js directories. –  Travis R Jan 12 '13 at 18:09
Have you tried to search for it from root using : find / -type f -name power.js –  nesyphlopanuri Jan 13 '13 at 14:32
Ran that, nothing found. –  Travis R Jan 14 '13 at 22:46

The issue is related at KDE environment. I have the same problem with MintMAYA KDE_version. When I worked with Mint9_Gnome a very useful pop-up appeared when a certain level of low-power was reached (auto-configured out_of_the_box on fresh installs). Very very annoying being shutted down without advice and no help founded even googling a lot :(

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(This would be a comment, but I do not have enough reputation)

re: hdgarrood 's answer, setting cron to run notify-send actually turned out to be painfully finicky. (I think crontab -e does persist across reboots by default, fortunately). I followed several guides, I'm not sure what exactly fixed it in the end, but here is my full setup for running the checker every 5 minutes:

$ crontab -e

*/5 * * * * sh /home/nrw/.notify-send_setup
*/5 * * * * sh /home/nrw/.battnotif

$ cat .notify-send_setup

touch $HOME/.dbus/Xdbus
chmod 600 $HOME/.dbus/Xdbus
env | grep DBUS_SESSION_BUS_ADDRESS > $HOME/.dbus/Xdbus
echo 'export DBUS_SESSION_BUS_ADDRESS' >> $HOME/.dbus/Xdbus

exit 0

$ cat .battnotif

export DISPLAY=:0

if [ -r "$HOME/.dbus/Xdbus" ]; then
    . "$HOME/.dbus/Xdbus"

battery_level=`acpi -b | grep -P -o '[0-9]+(?=%)'`

# I tried to only notify when not charging, but could not get it to work
# STATUS=$(cat /sys/class/power_supply/ADP1/online)
# if [ $battery_level -le 15 ] && [ $STATUS == "0" ]

if [ $battery_level -le 15 ]
    /usr/bin/notify-send -u critical "Battery low" "Battery level is ${battery_level}%!"
    echo 'batt low' >> /home/nrw/cron.log

echo 'ran batt' >> /home/nrw/cron.log

Make sure to chmod +x the bash scripts.

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(This would be a comment to orangenarwhals answer, but I do not have enough reputation either..)

I do now run the following:

$ crontab -e
*/5 * * * * /home/<my username>/bin/checkLowBattery

$ cat /home/<my username>/bin/checkLowBattery

POWERSUPPLY="/sys/class/power_supply/ACAD/online" # could be different on your system!
TOO_LOW=20 # how low is too low?
ICON="/usr/share/icons/ubuntu-mono-dark/status/24/battery-low.svg" # eye candy

export DISPLAY=:0

BATTERY_LEVEL=$(acpi -b | grep -P -o '[0-9]+(?=%)')

    /usr/bin/notify-send -u critical -i "$ICON" -t 3000 "Battery low" "Battery level is ${BATTERY_LEVEL}%!"

exit 0

As you can see this is just orangenarwhals code with some changes:

  • no dbus trickery, somehow I didn't need it
  • put some "constants" into variables at the beginning of code
  • implemented warnings only when battery is not charging (take a look at man test, it explains how to do ANDs, among other things.)
  • added icon (find some candidates on your system with something like: $ find /usr/share/icons/ -iname "*batt*low*")
  • expiry-time in milliseconds

don't forget to chmod +x your scripts, you can then run them directly from cron(tab), no need for sh.

(This works on Ubuntu using Xmonad.)

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