Ubuntu – The battery indicator in Unity panel not showing up

Here are no problem it seems.
Soon, power consumption counted by Windows do not point actual state, because Windows is hungry and forced "to be a bit wrong" to user. It's my very subjective opinion.

Hovewer, it is very relativistic question due to very relative nature of an ACTUAL STATE term.

A very many ways exist to explain why for Windows 60% is actual but EQUAL for actuals Ubuntu 82%'s. Most simple is about differences between Windows and Ubuntu paradigms.

update 1

Try to test your environment with fwts :

sudo add-apt-repository ppa:firmware-testing-team/ppa-fwts-stable
sudo apt-get update
sudo apt-get install fwts

Read: wiki.ubuntu.com/Kernel/Reference/fwts

update 2

Thus battery.log shows that power ACPI interface disabled.
It means you have first solution for your problem by enabling power interface in BIOS.
Or if this behavior initiated by boot-parameter you need to find correct value.

update 3

Obviously booting parametrization have weight here.
New readings based on updates: UEFIBooting

Most actual parameters (WARNING! Use only correct parameters referred to your config) :

 acpi
 noefi
 acpi_osi
 apm  

Kernel boot parameters Documentation

update 4

Also you can try to test output parameters with acpi program:

sudo apt-get install acpi
acpi -V

Finally all my web surf point to: ThinkPad ACPI Extras Driver

And: Lenovo Diagnostics (Linux Bootable CD).

Note: Try steps 4/5 first, it may be fixed with 1st hit.

Below the extended instruction to debug the problem with the indicator.

1. Check if indicator-power-service is running:

   ps ax | grep indicator-power
   

2. If it's running, try reset its settings then restart it:

   dconf reset -f /com/canonical/indicator/power/
   pkill -f indicator-power-service
   

   No success, locate it then try it from terminal (looking for any errors in output):

   sudo updatedb; locate -r indicator-power-service$
   

   My system is 64bit, So:

   /usr/lib/x86_64-linux-gnu/indicator-power/indicator-power-service
   

   If it works with command, then some thing wrong with its autostart.

3. As it was checked, it isn't running on start up. Verify the existence of:

   /usr/share/upstart/sessions/indicator-power.conf

   description "Indicator Power Backend"
   
   # Want to move to indicator-services-[start|end], but that's not all
   # there yet.  Use the signals that exist today for now.
   
   start on indicators-loaded or indicator-services-start
   stop on desktop-end or indicator-services-end
   
   respawn
   
   exec /usr/lib/x86_64-linux-gnu/indicator-power/indicator-power-service
   

   /etc/xdg/autostart/indicator-power.desktop

   [Desktop Entry]
   Type=Application
   Name=Indicator Power
   Exec=/usr/lib/x86_64-linux-gnu/indicator-power/indicator-power-service
   NotShowIn=Unity;
   NoDisplay=true
   StartupNotify=false
   Terminal=false
   

4. This works for me with a fresh Ubuntu 14.04, Modifing indicator-power.desktop for autostart conditions similar to the other indicators. (Submitted bug report lp#1330302)

   sudo nano /etc/xdg/autostart/indicator-power.desktop

   Remove:

   NotShowIn=Unity;
   

   Replace it with:

   OnlyShowIn=Unity;XFCE;GNOME;
   AutostartCondition=GNOME3 unless-session gnome
   

5. Logout/Login

Well if it didn't work:

1. Try purge it then reinstall it:

   sudo apt-get remove --purge indicator-power
   sudo apt-get install indicator-power
   

   Reboot, Check again

2. No success, as workaround you can run it this way (you may close terminal after this):

   /usr/lib/x86_64-linux-gnu/indicator-power/indicator-power-service & disown $!
   

   & run it in background
   disown $! command to detach a process for current terminal, $! variable that hold PID of last process run in background

   Or better if add it to user startup applications, see How do I start applications automatically on login?