Laptop battery status notifier inspired by http://www.wired.com/gadgetlab/2013/09/laptop-battery. Images are Ubuntu specific.

battery.py

#!/usr/bin/env python

# Inspired by the article http://www.wired.com/gadgetlab/2013/09/laptop-battery
#
# Info about battery life vary depending on who you ask from. So I'm not sure
# what to believe anymore. Anyhow wrote this because the last time I tried at
# writing a battery status notifier, I failed.
#
# I couldn't live with that memory!

import pynotify
import time

F_BAT_CAPACITY = '/sys/class/power_supply/BAT0/capacity'
F_BAT_STATUS = '/sys/class/power_supply/BAT0/status'
UNPLUG_IMG = '/usr/share/icons/Humanity/status/48/gpm-primary-080-charging.svg'
PLUG_IMG = '/usr/share/icons/Humanity/status/48/gpm-primary-040.svg'
POLL_INTERVAL = 300 #5 minutes


def notify(title, message, image):
    pynotify.init('BATTERY-HEALTH')
    notice = pynotify.Notification(title, message, image)
    notice.show()

    return


def battery_check():
    notified_to_plug = False
    notified_to_unplug = False

    while True:
        with open(F_BAT_CAPACITY, 'r') as fcharge:
            charge = int(fcharge.readline())

        with open(F_BAT_STATUS, 'r') as fstatus:
            if fstatus.readline() == 'Discharging':
                plugged = False
            else:
                plugged = True

        if charge >= 80 and (plugged and not notified_to_unplug):
            notify("Unplug me from power",
                   "battery level is %s" % charge,
                   UNPLUG_IMG)
            notified_to_unplug = True
            notified_to_plug = False
        elif charge <= 40 and (not plugged and not notified_to_plug):
            notify("Plug me back on power",
                   "battery level is %d" % charge,
                   PLUG_IMG)
            notified_to_plug = True
            notified_to_unplug = False
        time.sleep(POLL_INTERVAL)

if __name__ == "__main__":
    battery_check()