Linux Mint does not come with battery watcher. It is a bit annoying when your laptop shuts down, all because you have forgotter to plug it in.

After a bit of research found out this small bash script which does exactly what I wanted.

The script will watch the battery and will notify you once it goes under a specified percentage

#!/bin/bash

# DEBUG:
notify-send " Listening for battery status " -t 8000

# Set the alert tone for battery, or leave it as empty quotes.
# .mp3 or .ogg audio file
alarm="/your/path/battery_notification.ogg"
# Notify when below this percentage
warning_level=70
# How often to check battery status, in minutes
check_interval=2
 
while true; do
  battery_level=$(acpi -b \
    | cut -d, -f2 | cut --characters=2,3,4 \
    | sed 's/%//g')
  charging=$(acpi -b | grep -c "Charging")
 
  # When battery is low, and not already charging
  if [ $battery_level -lt $warning_level ] &&
     [ $charging -eq 0 ]
  then
    play -q -v 0.40 "$alarm" &
    notify-send " Low battery: ${battery_level}% " \
      " Plug into mains power " -t 8000
  fi
 
  sleep ${check_interval}m
done

So how to install it on Linux Mint.

1. Copy the script and paste it in a file called battery_status.sh

2. Open "Startup Applications" from your main menu

3. Using the "Browse" button select your file

4. Give it a delay of say 30 seconds, and save

The next time you restart your Linux Mint, you will get a nice notification once the battery starts to dwindle,