I have bought new battery for my laptop. It is running Ubuntu MATE 16.04.5 LTS.

This new battery have normal capacity, charging and provides long life :)

But I have small problem: when battery level goes under some level - the laptop shutdowns immediately. I remember, that it normally went to the suspend with old battery.

With new battery I can suspend manually and all suspend-related tests (such as pm-is-supported --suspend, pm-is-supported --hibernate, pm-is-supported --suspend-hybrid) returns 0, so these actions are supported.

For more predictive results I have reseted all settings with

gsettings reset-recursively org.mate.power-manager

So my GSettings reports the following:

$ gsettings list-recursively | egrep "critical|action|low|time" | grep -i power | sort -u

org.mate.power-manager action-critical-battery 'hibernate'

org.mate.power-manager action-critical-ups 'shutdown'

org.mate.power-manager action-low-ups 'hibernate'

org.mate.power-manager action-sleep-type-ac 'suspend'

org.mate.power-manager action-sleep-type-battery 'hibernate'

org.mate.power-manager idle-dim-time 10

org.mate.power-manager info-history-time 21600

org.mate.power-manager notify-low-capacity true

org.mate.power-manager notify-low-power true

org.mate.power-manager percentage-action 2

org.mate.power-manager percentage-critical 3

org.mate.power-manager percentage-low 10

org.mate.power-manager show-actions true

org.mate.power-manager time-action 120

org.mate.power-manager time-critical 300

org.mate.power-manager time-low 1200

org.mate.power-manager use-time-for-policy true

In /etc/UPower/UPower.conf I have default values:

$ cat /etc/UPower/UPower.conf | grep -v ^# | egrep "Critical|Low|Action|Time"

PercentageLow=10

PercentageCritical=3

PercentageAction=2

TimeLow=1200

TimeCritical=300

TimeAction=120

CriticalPowerAction=HybridSleep

The MATE Power Management Preferences (mate-power-preferences) does not have GUI element to set critical battery level:

Where should I set critical battery level for hibernate or suspend from MATE GUI?

Will changing value via GSettings or Dconf change value in UPower.conf?

Where else should I set the action on critical battery level?

Updates:

1. Laptop model is Asustek UX32A.

Output of cat /sys/class/power_supply/BAT0/uevent:

POWER_SUPPLY_NAME=BAT0

POWER_SUPPLY_STATUS=Discharging

POWER_SUPPLY_PRESENT=1

POWER_SUPPLY_TECHNOLOGY=Li-ion

POWER_SUPPLY_CYCLE_COUNT=481

POWER_SUPPLY_VOLTAGE_MIN_DESIGN=7400000

POWER_SUPPLY_VOLTAGE_NOW=7400000

POWER_SUPPLY_POWER_NOW=11151000

POWER_SUPPLY_ENERGY_FULL_DESIGN=48248000

POWER_SUPPLY_ENERGY_FULL=50038000

POWER_SUPPLY_ENERGY_NOW=46346000

POWER_SUPPLY_CAPACITY=92

POWER_SUPPLY_CAPACITY_LEVEL=Normal

POWER_SUPPLY_MODEL_NAME=UX32-65

POWER_SUPPLY_MANUFACTURER=ASUSTeK

POWER_SUPPLY_SERIAL_NUMBER= 

and output of upower --dump:

Device: /org/freedesktop/UPower/devices/line_power_AC0

  native-path:          AC0

  power supply:         yes

  updated:              Sun Nov  4 12:43:52 2018 (233 seconds ago)

  has history:          no

  has statistics:       no

  line-power

    warning-level:       none

    online:              no

    icon-name:          'ac-adapter-symbolic'



Device: /org/freedesktop/UPower/devices/battery_BAT0

  native-path:          BAT0

  vendor:               ASUSTeK

  model:                UX32-65

  power supply:         yes

  updated:              Sun Nov  4 12:45:52 2018 (113 seconds ago)

  has history:          yes

  has statistics:       yes

  battery

    present:             yes

    rechargeable:        yes

    state:               discharging

    warning-level:       none

    energy:              46.509 Wh

    energy-empty:        0 Wh

    energy-full:         46.916 Wh

    energy-full-design:  48.248 Wh

    energy-rate:         11.514 W

    voltage:             7.4 V

    time to empty:       4.0 hours

    percentage:          92%

    capacity:            81.4562%

    technology:          lithium-ion

    icon-name:          'battery-full-symbolic'

  History (charge):

    1541324752  92.000  discharging

  History (rate):

    1541324752  11.514  discharging



Device: /org/freedesktop/UPower/devices/DisplayDevice

  power supply:         yes

  updated:              Sun Nov  4 12:45:52 2018 (113 seconds ago)

  has history:          no

  has statistics:       no

  battery

    present:             yes

    state:               discharging

    warning-level:       none

    energy:              46.509 Wh

    energy-full:         46.916 Wh

    energy-rate:         11.514 W

    time to empty:       4.0 hours

    percentage:          92%

    icon-name:          'battery-full-symbolic'



Daemon:

  daemon-version:  0.99.4

  on-battery:      yes

  lid-is-closed:   no

  lid-is-present:  yes

  critical-action: HybridSleep

2. TLP is not installed on my system.

3. I have reseted all settings with no luck. Todat I asked question on Ubuntu-MATE.community.

GUI method

From: Change Critical Battery Level and Action in Linux Mint 18 Cinnamon
you can install dconf-editor using:

$ sudo apt-get install dconf-editor

Then go to org -> cinnamon -> settings-daemon -> plugins -> power

• Default settings are (in %):


• Critical battery action: hibernate


• Critical: 2


• Action: 2


• Low: 10

Exercise caution and tweak to your heart’s content 🙂

Original Answer and edits below

Review your current settings with:

$ gsettings list-recursively | grep critical

org.gnome.settings-daemon.plugins.power critical-battery-action 'shutdown'

org.gnome.settings-daemon.plugins.power percentage-critical 3

org.gnome.settings-daemon.plugins.power time-critical 300

Change your critical-battery-action

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

Linux Mate differences

When using Linux Mate you need to substitute org.gnome with org.mate and possibly change your keys. From ArchWiki:

Battery discharge

To disable the notification on battery discharge, run:

$ gsettings set org.mate.power-manager.notify-discharging false

However in Ubuntu there is no equivalent.

Find all Mate power settings

To find all Mate power settings use:

$ gsettings list-recursively | grep power-manager

In Ubuntu you would use:

$ gsettings list-recursively | grep plugins.power

I still can't find GUI solution for my problem. So I switched to semi-GUI solution.

I fixed this issue by using other battery level indicator - it is named fdpowermon:

Description-en: simple battery power monitor for laptops with ACPI

fdpowermon is a simple perl script that installs an icon in a system tray compatible with the freedesktop.org specification.

Every three seconds, fdpowermon calls acpi to find out what the current
battery level is. It will set the output of the acpi command as a
tooltip text, and will update the used icon as appropriate.

In addition, fdpowermon can optionally call perl subroutines when the
power reaches a given level. No such subroutines are provided or
enabled by default, however.

So I have installed it

sudo apt-get install fdpowermon

and created configuration folder for this application with:

mkdir -p ~/.config/fdpowermon/

and placed here two files:

1. file with my modified theme (in discharging array note the 3rd element 20:battery-low.png, it will be used to suspend in Perl script):

cat << EOF > ~/.config/fdpowermon/theme.cfg 

[mytheme]

steps = 8

dir = /usr/share/icons/oxygen/22x22/status

# The below line makes fdpowermon not show an icon when the power is

# connected and the battery is completely full. This is by design,

# because that's how the author likes to use the software, and he is of

# the opinion that it's easier to ship software configured just the way

# he likes it rather than to have to reconfigure things.

#

# Requests are often made to change this default. This will not happen,

# but it's an easy change: just change the last entry in this "charging"

# configuration so that it says "100:battery-charging.png" rather than

# "99:battery-charging.png", and you're done!

charging = 0:battery-charging-low.png, 10:battery-charging-low.png, 20:battery-charging-caution.png, 30:battery-charging-caution.png, 50:battery-charging-040.png, 70:battery-charging-060.png, 90:battery-charging-080.png,100:battery-charging.png

discharging = 2:battery-missing.png:battery-low.png,10:battery-low.png, 20:battery-low.png,30:battery-caution.png,50:battery-040.png,70:battery-060.png,90:battery-080.png,100:battery-100.png

EOF

2. Perl script file with dbus suspend action:

cat << EOF > ~/.config/fdpowermon/theme.pl

# Copy this file to ~/.config/fdpowermon/theme.pl.

#

# If you don't like the 'default' theme, define a new one by copying

# /etc/fdpowermon/theme.cfg to ~/.config/fdpowermon/theme.cfg and

# renaming/adjusting the 'default' theme there to something new.

# Don't forget to replace "default" below with your new theme name.

#

# See the manpage fdpowermon(1) for full details on what you can do

# here.



# define a suspend action

sub suspend {

    system("dbus-send --print-reply --system --dest=org.freedesktop.login1 /org/freedesktop/login1 org.freedesktop.login1.Manager.Suspend boolean:true");

}



# initialize our theme, from /etc/fdpowermon/theme.cfg or

# ~/.config/fdpowermon/theme.cfg

my $theme = fdpowermon::theme::get_theme("mytheme");



# on the discharge event for the lowest element in the list of steps (0 = first

# in the index, "d" for discharge), call the "suspend" sub defined above

$theme->set_event( 2, &suspend, 'd' );

EOF

(the DBus suspend command came from this great answer).

And finally I have disabled MATE Power Manager battery indicator with

gsettings set org.mate.power-manager icon-policy 'never'

and created auto-start desktop file to have fdpowermon shown in the tray instead:

mkdir -p ~/.config/autostart



cat << EOF > ~/.config/autostart/fdpowermon.desktop 

[Desktop Entry]

Type=Application

Exec=fdpowermon

Hidden=false

X-MATE-Autostart-enabled=true

Name[en_US]=fdpowermon

Name=fdpowermon

Comment[en_US]=

Comment=

EOF

As the result I have nice-looking battery icon in the tray from to and and system automatically suspends on 20% battery level (the level is configurable, but my new battery seems to report low values wrongly).