How do I set battery full alert tone in ubuntu 18.04 to save battery wear out?

Question

My battery has gone faulty for the third time now. Now I want to set an alarm when my battery charge reaches 90%, so that I can disconnect it.

Can someone help me in setting that up?

Answer 1

I don't like to install extra programs and utilities on my laptop, so I am thinking about a solution without acpi. Inspired by @pomsky's response, the below scripts may be a better solution.

Update: It does detect if the battery is already fully charged thanks to @mdebusk and @blaze-fire(krishan singh)

For Gnome:

#!/bin/bash
while true
    do 
        export DISPLAY=:0.0
        battery_level=`cat /sys/class/power_supply/BAT0/capacity`
        battery_status=`cat /sys/class/power_supply/BAT0/status`
        if [ $battery_status = "Charging" ] && [ $battery_level -ge 85 ];
        then
            notify-send -u critical "Battery fully charged"
        fi
        sleep 120
    done

For KDE:

#!/bin/bash
while true
    do 
        export DISPLAY=:0.0
        battery_level=`cat /sys/class/power_supply/BAT0/capacity`
        battery_status=`cat /sys/class/power_supply/BAT0/status`
        if [ $battery_status = "Charging" ] && [ $battery_level -ge 85 ];
        then
            kdialog --msgbox "Battery fully charged" 5
        fi
        sleep 120
    done

as you can see, the only difference is in the notification systems of KDE and Gnome . We use /sys/class/power_supply/BAT0/ facilities instead of acpi. make the script executable: chmod +x SCRIPTNAME.sh, then add it to startup.

hope this help.

Answer 2

Probably not the best way, but you can do something like the following.

1. First you'll need acpi. Install it by running

   sudo apt install acpi
   

2. Next you need to create a bash script. Create an empty text file, say battery-full.sh and add the following lines

   #!/bin/bash
   while true
       do
           export DISPLAY=:0.0
           battery_level=`acpi -b | grep -P -o '[0-9]+(?=%)'`
           if on_ac_power; then                                #check if AC is plugged in
               if [ $battery_level -ge 90 ]; then              #check if the battery level is over 90%
                   notify-send -u critical "Please unplug your AC adapter" "Battery level: ${battery_level}% (charged above 90%)" -i battery-full-charged
                fi
           fi
         sleep 300                                             #wait for 300 seconds before checking again
   
       done
   

3. Make the script executable and run it. You'll get a persistent notification if the battery is charging and the level is over 90%.

You can also get a sound alert by adding a suitable a audio-playing command after the notify-send command in the script above. For example you can you the play command from the sox package (for other options, see this). First install it by running

sudo apt install sox

Then modify the notify-send line in the script as follows

notify-send -u critical "Please unplug your AC adapter" "Battery level: ${battery_level}% (charged above 90%)" -i battery-full-charged; play /path/to/audio-file

(Replace /path/to/audio-file by a valid path to an actual audio file present in your system).

You may also consider adding the script to your startup applications so that it starts automatically every time you boot your laptop.

Answer 3

Another option is to set the battery charge limiter to say 60% to 80% if you aren't planning on taking it on the road. However for my laptop at least I can only change it in Windows as this answer details:

• Re: Plugged in, charging but won't pass 70%

The reason why your battery would stay upto 70% and not charge further could be due to an option called "Desktop Mode" which might be enabled. Desktop mode helps in disabling the battery to charge upto 100% to maximize the life of the battery. This option can also be disabled. To disable this option:

• Right-click the battery icon on the Windows notification area, and then click Dell Extended Battery life Options
• The Battery Meter dialog box is displayed, Click the Desktop Mode tab
• Select the option to disable this feature
• Then, click OK

I dual boot Ubuntu and Windows 10 so it's not a big deal to change the battery charge limiter. I don't know of any apps to do this in Linux. It would be a nifty little C program to write for my inaugural journey into the Linux Kernel coding though.

Answer 4

Building off of @pornsky's answer, the format of the acpi output wasn't working with @pornsky's code, so I modified it a little bit. The following script got the job done for me.

#!/bin/bash
while true
    do
        on_ac=`acpi | grep -o 'Charging'`
        battery_level=`acpi -b| grep -P -o '\d+(?=%)'| sed -n 2p`
        if [[ "$on_ac" == "Charging" ]]; then                                #check if AC is plugged in
            if [ $battery_level -ge 90 ]; then              #check if the battery level is over 90%
                notify-send -u critical "Please unplug your AC adapter" "Battery level: ${battery_level}% (charged above 90%)" -i battery-full-charged
             fi
        fi
      sleep 300                                             #wait for 300 seconds before checking again

    done

Check out his answer for more depth

Answer 5

Building on @Regantos answer for KDE:

• Fixing small syntax errors like missing space in line 9 and removing redundant nested if statements.
• Now make script executable using sudo chmod +x /path-to-script/
• Add script as login script in background services in kubuntu which makes it run automatically after you login

While copying script beware of the intended spaces as they will affect the output.

Note: In order to play audio you will have to install Sox

#!/bin/bash
while true
    do 
        export DISPLAY=:0.0
        battery_level=`cat /sys/class/power_supply/BAT1/capacity`
        battery_status=`cat /sys/class/power_supply/BAT1/status`
        if [ $battery_status = "Charging" ] && [ $battery_level -ge 85 ];
        then
                play /path-to-mp3-file;  // to play alert sound
                kdialog --msgbox "Battery fully charged";
        fi
        sleep 120       // cooldown time
    done