Trying to get 4+ hours of battery life with linux

As it stands, I can only get 2 hours worth of battery life on power saver mode*. Though windows vista serves me well for my gaming purposes, I would like to consider trying to dual boot with a linux distro so I can use my laptop as a long life word processor.

This distro** would have to boot into a mode that should use 25% of my cpu at maximum***, and at most, 512 MB RAM. Under these settings, it should smoothly be able to use abi word, and browse the internet via firefox at the same time.

Now the my two questions, how would I go about doing that, and would it achieve 4 hours of battery life , plus the above criteria?
Please Help.

My laptop:
Gateway M-6827.

My Specs:
Gateway Official Site: Products - M-6827 Pacific Blue, Notebooks, Product Details
2.00 GHz Intel Core 2 Duo
3 GB DDR 2 RAM
Intel X3100 with 348 VRAM
15.4 in screen
1920x 1280 resolution (in vista)

*50% CPU, 6x Multiplier.
** I'm thinking **** Small Linux or something fast like that.
***does that make a difference? my multipliers only go down to 6x
stukpixel is offline Reply With Quote

 

I think you ask for the impossible, and even worse, you want to go about it the wrong way. Limiting the amount of RAM you use is a very, VERY bad way to save power. You want EVERYTHING to be in RAM, and keep the hard drive shut down. Your screen backlight also eats up a ton of power, so you have to keep that at it's dimmest. Not to mention your graphics card, which you can't adjust much, except for running in simple VGA mode, so you probably want to completely disable X, and then there are the rest of the chips on your computer. The wireless chip uses quite a lot of power, so you'll want that off as well. Same with bluetooth. The frontside bus will always be using a non-trivial amount of juice.

After doing all that, you might be able to squeeze out 3 hours of battery life, as compared to your powersaver mode. Just get another battery, or a larger battery.

 

I'm not entirely sure about the accuracy over your statement about ram, but I do know that it is my processor that is eating most of my power.

Quick Test:
Normal Mode: 1hr 17 mins
Power Saving Mode: 2hr 10 min

Knowing that power saving mode underclocks my processor automatically to 50% at 6x multiplier, I would say that it is indeed a large part of my power consumption.

Also, I am aware of the basics of power saving, so there is no need to inform me of the power of screen brightness. But then again, I failed to mention that vista automatically lowers the brightness of my laptop on battery to the bare minimum.

 

I couldn't even find the estimated battery life for your model from Gateway's website. It isn't clear whether that much battery life is even possible, unless you've had around 4 hours in Windows (presumably Vista).

 

**** Small Linux will give you severely limited power saving options, if any at all. It would be best to go with a highly customizable (and highly technical) distro like Debian, Gentoo, or Arch.

In any case, getting 4 hours out of a 2-hour battery might be impossible. The only way to achieve it (if it is at all possible) would be to not only shut off OS services, but to completely turn down power usage at the hardware level, as has already been stated.

 

does that mean **** small linux can't underclock the cpu/ take advantage of intel speedstep technology?

is gentoo capable of doing so and operating smoothly under very limited settings?
(i.e., 1 core 2 duo core at 500 mhz)

 

Gentoo could do it, but getting advanced power management set up in a distro like Gentoo requires some knowledge and skill. I think a general-purpose distro would be more suitable for you; you could still modify it to your tastes.

 

I don't think so. **** Small Linux is minimalist to the extreme, as demonstrated by its ridiculously small size. Also, you will need much more than SpeedStepping to achieve your 4-hour goal. You will definitely want to look into ACPI, HAL, and perhaps PHC (voltage control).

How Gentoo will act will depend entirely on what kind of GUI apps you put on it. At 500MHz, you should forget about GNOME or KDE and use a basic window manager like Openbox, and be very picky about what apps to install. (I use Openbox and Xfce/LXDE apps on an underclocked system and it's very smooth.)

Also, you should know that of the three distros I labeled above as highly technical, Gentoo is the most.

 

I was planning on doing some undervolting for my laptop, but I created this thread is so I can figure out what distro I should use.

I'm going to try out gentoo to see if it meets my basic criteria as a word processor/web surfer, and then start my modifcations from there.

 

from the way you say this i think its safe to assume you dont know much about gentoo correct? just so you know, gentoo come with almost literally *nothing*- no gui, no software, just an OS (that is fully customizable and my favorite ) when youre done installing all you have is a command line (and the tools to build your OS)

the whole point of gentoo is to offer you as much choice as possible. so you choose whether you want to install X, and from there what desktop environment (gnome, kde, but since youre going for power save probably something like openbox or fluxbox) and then what sort of word processor and browser you want. so youre probably looking at installing X, a desktop environment, firefox or opera (or something else im not a browser expert), and a lightweight word processor like abiword.

i personally will be using gentoo as a power saving OS on my laptop when i get it, but bear in mind that it will take a LOOONG time to set up, *especially* if youve never worked with it before.

 

I wouldn't recommend a beginner to start with Gentoo. I have 1.5 years of experience with Ubuntu, and still find Archlinux a bit steep.

 

^ Yeah, especially considering that undervolting requires that you compile a new kernel to patch it.

 

oh i definitely wouldnt recommend gentoo to a beginner either.

thanks bog for the heads up on the undervolting, i had never looked into it with gentoo before but i will be soon