Need help optimizing battery life.

I tend to get about half the battery life in Xubuntu that I do in Windows XP. This was a deal breaker on my other laptop (going from ~8 hours to ~4), but it's not as big of an issue on this laptop (going from ~4 hours to ~2). I would however be much happier if I could get myself up to maybe 3/4 the battery life of XP, not half. I've downloaded powertop, but have had little luck with it because I do not know how to get the settings to stick. I found a pretty good guide on the Ubuntu forums: http://ubuntuforums.org/showthread.php?t=729644

The problems I have are:
This guide is for Gutsy/Hardy, and I am using Intrepid. I didn't realize how dramatically different things can be in different versions until I started playing around with some guides designed for other versions than Intrepid.
This guide is for new laptops (specifically states with SATA drives), I have a Compaq Evo N610c. So fairly old, and PATA interface.
I'm a pretty big linux newbie, so anyone want to lend me a hand?

Thanks much,
Hep!

 

this is one of the reasons why i stopped using ubuntu.

if battery management is worse than in windows then i dont know why people praise ubuntu so much. its supposed to use less resources so shouldnt that equate to better battery life as well?

 

resources != battery life

The drivers available for Linux just usually don't have much power management features (I believe this was one of the things they were really striving to change in the next release).

 

I'd guess that the Evo N610c will never be much of a power saver using Linux. Why, you might ask? I'd say it's because of the legacy drivers for the Radeon 7500 video chip, they don't support downclocking on battery. There is the proprietary fglrx driver with power management support, but it does not and probably never did work with that old chip anyway.

Oh, and BTW, a way to use the Powertop suggestions is also shown in the thread you mentioned. Just replace the lines the OP suggests with the lines Powertop gives you. Might be a bit harder to figure out how to put the defaults back on AC, though, as Powertop never suggests the other way around

 

Yeah that was part of my issue - I don't know what the default settings are and I don't know how to determine them.
I also don't know how to apply those scripts in Intrepid.

 

In that case, Intrepid shouldn't be different to Hardy. The difference of your 5 years old laptop to a recent one does matter a bit, but I'm sure half a year of Linux development doesn't.

 

Tweaking power consumption under Linux distros is limited because most of the work has been done for you. Further tweaking could involve editing HDparm.conf, using Powertop to find ways of cutting power consumption and then copying the commands into an executable script that runs on battery.

It is an unfortunate truth for most Linux distros, however in some cases choosing the right hardware can minimise this apparent weakness, or in some cases it can even give you better power consumption under Linux. For example, my IBM T42 consumes about 12W when mobile (less than Lenovo's new T400), and so it can achieve up to 6 hours of battery life (compared to 4 under XP).

 

My power consumption isn't too drastically different, but I still tend to boot Windows for long trips. I've heard one good recommendation is the CPU-applet.