Battery charged notification

Load-shedding is driving us nuts! My solution is to move all my works to laptop and buy a spare battery. I think this is more cost effective and energy saving than buying expensive inverters. I've got an extra 8-cell battery for my laptop and altogether I have 6+ hours of backup.

But the problem is I keep forgetting to charge the batteries. The one in laptop starts charging when light is back but when it's done charging I forget to switch battery.

The solution lies at /proc/acpi/battery/BAT1/state

$ cat /proc/acpi/battery/BAT1/state
present:                 yes
capacity state:          ok
charging state:          discharging
present rate:            1342 mA
remaining capacity:      2201 mAh
present voltage:         11432 mV

Our line of concern is 'charging state:' which can have one of three values - charging, discharging or charged. So here's a simple bash script to monitor this file for charged state and pop a message to switch the battery.

#!/bin/sh

charged=0
while : ; do
   if grep -iq 'charged' /proc/acpi/battery/BAT1/state
   then
      # nofify if previous state is uncharged
      if [ $charged = 0 ] ; then
         zenity --info --text "Battery charged. You might wanna charge another."
      fi
      charged=1
   else
      charged=0
   fi
   sleep 5m # wait for 5 minutes
done

Now put this program to System > Preferences > Sessions > Startup Programs.