Battery lasts less.

[bunkdeath]

Hello everyone.
Similar thread has already been posted, but long time ago.
I could not post the url since my post is less then 15.
Here is the last part of url.
forum/hardware-peripherals/141531-battery-lasts-lesser-time.html

But it is in middle of no where. My problem is the same. In windows, my battery lasts for about 3 to 3.5 hrs (according to running application), but in linux (I am using Fedora 14) my battery lasts less, for about an hour with lowest brightness, wifi off, running some application only (generally I use netbeans). I checked my running process, it shows only 6 to 10% of cpu use (in battery, i usually close unwanted application to minimize cpu usage, if it would help increase battery time).

What can I do to increase my battery time? Is it possible? Generally I see people writing battery time is increased in linux. I wonder if it could be possible in my case too.

I use Acer Aspire 4736z.

[Rubberman]

Depending upon the version of linux you are running, the power management tools vary. Since your are running FC 14, you should be able to manage the battery power by having the system reduce CPU frequency by a significant fraction. Example, my 2.5GHz Dell D630 laptop (running Ubuntu 10.10) reduces CPU speed to 800MHz (1/3 speed), or even 400MHz (1/6 speed) when the cpu is not actively processing stuff. I get a good 3-6 hours per charge that way.

[bunkdeath]

But how can I reduce CPU frequency? Any tips would help me.

[Rubberman]

You should be able to set the CPU power level by modifying the acpi settings for your processor cores. The files you want to change are /proc/acpi/processor/CPUX/limit, where CPUX is the CPU #, such as CPU0, CPU1, etc. Here is some documentation about how to do that:

limit
P-States are processor performance states (see file "performance" below), T-States are throttling states (see file "throttling" below). P0:T0 reflects 100% processor performance available, any increase means lower speed and lower power usage.
Operation        Command     Sample Output
Read             cat limit   active limit:   P0:T0
                             platform limit: P0:T0
                             user limit:     P0:T0
                             thermal limit:  P0:T0
Write            echo -n x:y > limit
with x being replaced by the performance state number and y being replaced by the throttling state number.
Such a user limit causes the system to decrease performance and power usage by setting at least these states. Platform and/or thermal limits might enforce even higher states.

[bunkdeath]

Sorry for the late response. So all my values are P0:T0, what should I write there to minimize the process usage. And also, this file seems refreshing every moment. Does changing this values remains forever? Please provide me, how to minimize these values.

[Roxoff]

There's a couple of little tips on here. It's aimed at the eee pc, but relates to Fedora. Scroll down to the 'Maximize battery life' section towards the end of the page, it's got some tips for using less juice.

I did this (on my Eee PC) and my battery monitor reports over 8 hours life on a full charge. I do have a brand new battery, though.

[bunkdeath]

Roxoff, thanks for the link, this helped me a bit. Now my battery lasts for 1hr 50 minutes with wifi on.

The CPU Frequency Scaling Monitor applet in fedora shows both my CPU not less then 1.2GHz used. And Hardware Sensor Monitor shows my CPU temperature not less than 57°C (after running my laptop for sometime). Sometimes my laptop closes due to high heating. Any method to decrease these.

[Roxoff]

Have you tried opening a terminal window and running the 'top' tool to see what's actually consuming your processor resources? This might show you what's going on - and something could be running continuously if your CPU usage doesn't drop.