Ubuntu 8.10: Crappy battery life

[Smeed]

I consistently get 4:35 minutes batter life at 100% but under XP its always 5:30+. Im not running compiz, bluetooth is turned off and Ive disable wired networking. What gives?

[Freddy]

This is the reason I didn’t go for Ubuntu on my NC10. XP is much better when it comes to battery life. But if you only get 5:30 in XP then something is also very wrong. You should be able to get 7+ hours (yes, with normal settings, 3-bar brightness, Wifi on etc.).

[Alfihar]

Have you tried installing/running powertop and see what it suggests?

I’ve heard that the power usage of the wireless card may be higher with the current ath5k module compared with Windows drivers.

[Smeed]

Ive tried powertop. It was always at 4:35. I realized I should have timed the battery life IRL and not trusted what the icon said. I vaguely remember having much more battery life in Ubuntu so I wiped my drive (except for the restore parition) and Ive started fresh. Ill see what I get for life with just the basics.

I never had 7+ hours in XP even with XP set to performance…. 🙁

[balkanhax]

[quote1229925432=Smeed]
I never had 7+ hours in XP even with XP set to performance…. 🙁
[/quote1229925432]

Performance = Less battery life

I’ve been able to get almost 8 hours on my machine (missed by about 10-15 minutes) by turning wi-fi/LAN off. My processes were OpenOffice and a SMART board software that I use for school.

[Alfihar]

I’ve just been running powertop, the power usage (estimate) is currently stable at around 6.8W, which estimates at 8.3 hours battery life, with around 24 wakeups-from-idle per second. This is with WiFi/LAN off.

With WiFi on and connected I get 8.3W which estimates at 6.9 hours, with around 43 wakeups-from-idle per second.

Both of these were with Compiz turned off. With WiFi and Compiz I get 8.5W which estimates at 6.5 hours, with 50 wakeups-from-idle per second.

For all the tests the screen was on around 25% brightness and fully usable, Bluetooth was disabled. Of course I don’t actually expect to get this length of time out of the battery as the tests were done when the machine was idle.

I am running Fedora 10, with various tweaks which are documented on the LessWatts.org site.

[pauq]

Which tweaks are you using? which ones are applicable

[Alfihar]

I am currently using:-

Increase the time for cached writes.

Code:

echo 1500 > /proc/sys/vm/dirty_writebac_centisecs

Switch on laptop mode, so it submits pending IO when the hard drive is woken up by the kernel.

Code:

echo 5 > /proc/sys/vm/laptop_mode

Enables power saving mode for the soundcard

Code:

echo 10 > /sys/module/snd_hda_intel/parameters/power_save

Code:

echo 1 > /dev/dsp

Disables the writing of timestamps to files when they are accessed.

Code:

mount -o remount,noatime /

Puts the hard drive into an aggressive power saving mode, though this may shorten the life of the hard drive. Not sure if I’m going to continue using this one as it is.

Code:

hdparm -B 1 -S 12 /dev/sda

I also modified this line in the /etc/rsyslog.conf file:-

Code:

*.info;mail.none;authpriv.none;cron.none /var/log/messages

changed to:-

Code:

*.info;mail.none;authpriv.none;cron.none -/var/log/messages

[Author]

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