How do I set the computer to suspend when battery is critically low?

Question

I accidentally clicked on the option "When power is critically low" under System Settings>Power. The original entry was blank, but the only two options after I clicked were Hibernate and Shutdown. I want to set it back to Suspend.

Answer 1

To change this setting back to suspend, use dconf-editor. Install it with

sudo apt install dconf-tools

Then, go to org.gnome.settings-daemon.plugins.power and change critical-battery-action to suspend.

Alternatively, in a terminal session use the command:

gsettings set org.gnome.settings-daemon.plugins.power critical-battery-action 'suspend'

The gsettings command is resident by default while dconf-editor requires installing via the apt command shown above.

Answer 2

I don't have sufficient rep to edit or comment, so if anyone would care to, this is a comment/edit for AtomHeartFather's answer.

You may also change the values for what percent is considered low/critical battery using dconf-tools. In the same power section, modify the following values to the desired percentages.

percentage-action

percentage-critical

percentage-low

Note: Special consideration goes to the percentage-action setting which will trigger the critical-battery-action setting.

Answer 3

There is no option to suspend available.

You cannot suspend when the power is critically low, to suspend you need power to save the session to RAM allowing you to resume quicker, if you loose power you loose the current suspend state.

Hibernate copies the current state to the hard drive, it is slower but you can turn off the power.

Shutdown is obvious - you will lose any data in the active session and have a new session on restart.

Answer 4

On latest version of Ubuntu the batter critical actions aren't available in the UI. However, you can set them up as below.

Edit /etc/UPower/UPower.conf and set

UsePercentageForPolicy=true
PercentageLow=20
PercentageCritical=8
PercentageAction=5
CriticalPowerAction=Hibernate

Now, restart the UPower systemd unit:

systemctl restart upower

Answer 5

I wrote a simple bash script which will do it on any linux... just add this script to startup... every two minutes the script checks for battery status and suspend if battery lower that 11%....

#!/bin/sh
flag=0
while [ 1 ]; do
  var=$(upower -i /org/freedesktop/UPower/devices/battery_BAT0| grep -E "percentage"| grep -o '[0-9]*')
  if [ $var -lt 11 ] && [ $flag -eq 0 ]; then
    systemctl suspend
    flag=1
  elif [ $var -gt 11 ] && [ $flag -eq 1 ]; then
    flag=0
  fi
  sleep 120
done

Answer 6

I had this problem.

I was extremely frustrated whenever my computer would blackout, while i was doing serious work.

I wrote a script to check the A/C Power sate every two minutes and hibernate when the power goes off. Please modify according to your battery's health. My battery could pnly work for two minutes after mains power outage.

#!/bin/bash

if [[ $(cat /sys/class/power_supply/AC0/online) == *0* ]] ; then

    echo 'On battery power'
    #pmi action suspend

    dbus-send --system --print-reply \
    --dest="org.freedesktop.UPower" \
    /org/freedesktop/UPower \
    org.freedesktop.UPower.Suspend

#else
#    echo 'On Ac Power'
fi

I put the script in a file called powerMon.sh and set that up as a cron job that runs every two minutes.

Answer 7

On 12.04 I used sleepd to suspend the machine when battery was low or the machine was idle.

Although sleepd is not packaged for Ubuntu 14.04, and has even been orphaned by its developer, it is possible to compile and install it yourself.

Installation on Ubuntu 12.04:

sudo apt-get install sleepd

Edit the file /etc/default/sleepd and set the following:

# -E       Do not poll events (since they weren't working for me).
# -c 60    Poll every 60 seconds.
# -u 900   Sleep after 15 minutes idle time when on battery,
# -U 3600  or 60 minutes when on AC power,
# -b 3     or when battery power drops below 3%.
# -H       (optional) Use upower instead of ACPI.

PARAMS="-E -c 60 -u 900 -U 3600 -b 3"

Then restart the daemon:

sudo service sleepd restart

It also has options to stay awake if there is network activity, but these stopped working for me.

On my machine, apparently ACPI was not always reporting the temperature correctly, so I needed to add -H to tell sleepd to read temperatures from upower instead of ACPI. I discovered the incorrect readings, after some unexpected syspends, by adding -v and watching the logfile with tail -f /var/log/*log | grep --line-buffered sleepd.

(I had a weird bug on one laptop with 12.04 that the machine would wake up again immediately after suspending, but only if sleepd was suspending due to low battery, not due to idle time. I hope you won't have that experience too! The problem never happened under 14.04.)

Answer 8

There's a way to disable suspension / power off completely.

gsettings set org.gnome.settings-daemon.plugins.power critical-battery-action 'false'

(in case it's showing critically low even at 100%)