Battery life

[mitchell2345]

Why is the battery life on my Dell 600m alot less when running fedora compared to Windows? I used to get about 3hrs in windows in fedora i get about 2.

What can i do to increase the life? I always have the LCD brightness on lowest.

Thanks,
mitchell

[cnayak]

I face the same problem on my Acer laptop too. Actually, things were a lot better in Suse 10.1, where an applet throttled the CPU frequency depending on the load. I'm not sure if FC 6 does the same by default. Nonetheless, I always set the CPU throttling factor at 25% in KLaptop. That way the laptop runs much cooler and there is no significant performance hit.

I hope some Linux guru here gives some better solution.

[Gallan]

what I can think I have noticed that brightness of monitor makes big hole to battery life. so is it same as in windows? next is how many services do you have running in linux and how about windows. I checked those in my own laptop and I got 20 minutes more battery life gurus can tell more...

[cnayak]

Hi gallan,

LCDs do make a huge difference in battery life. I turn it all the way down when I'm on battery.

[sailor]

My Acer Aspire gets about 1 - 1 1/2 hours ...but it is the same with Win or Linux. I am looking into buying a better battery which are available for many models.

[jmkreege]

my vaio fs-790 completely craps out when i unplug it. the battery life estimate is around 15 minutes and the battery charge percentage drops like crazy. i have the brightness on the lowest setting also. maybe the charge estimates just arent accurate?

[zeroelixis]

If you get about 15 minutes, its probably time to change the battery. As for CPU throttling, make sure the "cpuspeed" service is running:

service cpuspeed start

also: right click your gnome panel > add to panel > CPU scaling monitor

The two biggest drains on the battery are lighting the LCD and CPU frequency (higher frequency = more power drain). Also watching DVD's you can say bye bye to battery charge. If you listen to music try lowering the volume too, as well as removing any unnecessary USB/firewire or other peripherals. And if you have a wireless card and not using it, look for the switch to turn it off, it all adds up!

I have noticed on some laptops the charge being reported incorrectly presumably because of a strange BIOS/ACPI, but normally your laptop should have some way of telling you its going to sleep, i.e - a rapidly flashing LED.

Generally I have not noticed any difference when using FC6 compared to when I had Windows on it, which only adds to my smugness.

[jmkreege]

its not the battery. it last 2 hours when running windows. i have tried enabling the cpu speed monitor in the task bar, and when it pops up it says that throttling is not supported. i checked and i definitely have the i686 kernel. when running windows, no estimate for remaining battery life time is available, it only gives the remaining percentage. the rapid battery drop starts as soon as i unplug it with nothing running and wireless enabled.

[zeroelixis]

Do you get any error messages when starting cpuspeed the way I mentioned above? (as root)

[jmkreege]

no i didnt get any error messages when initializing the cpuspeed service

You will not be able to modify the frequency of your machine. Your machine may be misconfigured or not have hardware support for CPU frequency scaling.

i got that when adding the monitor to the sytem tray

[jmkreege]

if i go into the services manager it still says that cpuspeed is stopped, even if i manually start or restart it

[zeroelixis]

Does a:

modprobe cpufreq_ondemand

Give you any errors?

[jmkreege]

nothing at all

[jmkreege]

using uname -a i get:

Linux localhost.localdomain 2.6.19-1.2895.fc6 #1 SMP Wed Jan 10 18:32:37 EST 2007 i686 i686 i386 GNU/Linux

[mitchell2345]

yea mine says it starts but it doesnt.