I'm going to have a couple articles on the subject in the future but this article is going to address one of the biggest causes of poor battery performance.

Everything you do causes your battery to drain. Yes, even pressing the spacebar takes power. I know, it sucks.

I have a beautiful setup with Gnome. I don't think I could ask for anything else. A nice mac theme, a pretty desktop, compiz working fully with a nice pretty cube, my girlfriend on the top of the cube, an appealing set of screenlets that i can see by pressing F9.

I also have a fairly minimal setup with Fluxbox. No it's not that pretty and no I really don't care.

Which do you think takes less battery power? I haven't put the tests to it, but I can safely assume fluxbox is better on battery than gnome.

To do this, we first need to install fluxbox. While we're at it, let's install a few things that are a little less intensive than our gnome counterparts.

sudo aptitude install fluxbox irssi links2

It's not much, but switching firefox with links2 and switching xchat and pidgin for irssi will be a big benefit.

Don't bother going into it right away. You're going to want to get a nice pretty menu because the default pretty much sucks. Go to http://menumaker.sourceforge.net/ and download the latest copy. The instructions for installing are pretty straight forward. To use it, you will execute mmaker -fv Fluxbox.

To log into Fluxbox, log out of whatever you're in. When you're logging back in, change your session to Fluxbox.

Documentation:
https://help.ubuntu.com/community/Fluxbox
http://irssi.org/documentation
http://links.sourceforge.net/#man

Anyway... To the reason I started typing this. You're going to get irritated with having to choose every time you log into your computer and then have to say whether you want to make that default of just for the session. I did after about one day.

The solution is actually VERY easy.

1. Download the script I attached.
2. Move it to /usr/local/sbin/batcheck
3. Make sure it's executable with
chmod +x /usr/local/sbin/batcheck
4. Open the script that runs right before the login screen shows up
vim /etc/rc.local
5. Call the script - tack this into the script right before "exit 0"
/usr/local/sbin/batcheck
exit 0
6. Close the file

Now... for every user that you want this script to be active for, create a .batcheck file in their home directory.
For example, you would execute touch ~/.batcheck

That's it. When your computer turns on, it will set the display manager for every user that has .batcheck in their home directory.