Increase Battery Life on Ubuntu 8.10

7 02 2009

As I hang out between classes this semester, I find it very hard to find someplace both comfortable and with power near my class rooms. For that reason I’ve been looking into ways to increase my battery life on Ubuntu other than turning the screen brightness down to the point I can’t see anything. Most are these are obvious, some maybe not so much.

#1. Turn down the screen brighness. This really does make a huge difference.

#2. Unplug all USB devices. As nice as USB drives, USB mice, and USB humping rabbits are, they can draw up to 0.5 Amps each. With 4-8 USB ports on a standard laptop, you can easily kill your battery with a plethora of useless gadgets. Did you know you can even buy USB plasma balls?

rabbits#3. Make use of CPU scaling if your CPU has it. Ubuntu 8.10 did a fine job of configuring all this for me automatically, so all I had to do was right click my top panel, click add to panel, and choose the CPU Frequency Scaling application. With my Dell Vostro 1400 I can run my CPU at 800mhz, 1.2ghz, or 1.4ghz. There’s also options to idle at 800mhz and then bump up the clock speed when you’re doing anything intensive. Running it at 800mhz not only saves on battery life, but makes it run 5F-10F cooler. Note that the “ondemand” governor is actually better at saving power than the “powersaver” one. Also note that these settings aren’t saved, you’ll have to go research if you want them set to something other than ondemand by default when you boot.

#4. Disable polling on your optical drives. You won’t automount the CD anymore, but you’ll save a lot of power.

sudo hal-disable-polling --enable-polling --device /dev/cdrom
To start polling again
hal-disable-polling --enable-polling --device /dev/cdrom

#5. If you’re not using your Ethernet card, turn it off.

sudo apt-get install ethtool

sudo ethtool -s eth0 wol d

#6. If you are using the Ethernet card, disable the wifi. Almost all laptops now have a physical switch to disable the device and save on power.

#7. Run only the software you need. Even chat clients are constantly pinging servers and checking statuses, waking up your idle CPU and using power.

There are other ways to save on power, but the above options work for me. Like security, power saving is a balance between battery life and usability. Some can get by with greater sacrifices of usability than others, and even prefer it that way.



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