Tips to extend battery life for laptops and notebooks

Use powertop to see which programs are doing unneeded background processing such as beagle/tracker, weather notifications, gnome-do, and (if you don't need the internet) network-manager, mail-notifications.

Run sudo powertop --auto-tune to set all tunable options to their GOOD settings.

Install the package laptop-mode-tools.

This package is not necessary on newer versions of Ubuntu:

• Is "laptop-mode-tools" still relevant for 12.04 and the 3.x kernels?

I've been able to more than double the battery life of my netbook by turning off a bunch of services I don't need, and unloading their kernel drivers.

Use service --status-all to see what's running on your system, and service <service-name> stop to shut it down.

Use lsmod to see what kernel modules are loaded, and rmmod <module> to unload it.

If/when you want to bring things back, easiest way is to simply reboot.

Sometimes you also need to kill daemons or programs that are using the service or driver before they can be turned off. Look at output from ps aux to see what's running, and kill -9 <pid> to terminate them.

Services I usually turn off include: Ubuntu One, ssh, apache, databases, avahi, pulseaudio, cups, apparmor, acpi-daemon, bluetooth. Modules I unload: The whole audio stack, usb_storage, webcam drivers, wireless, bluetooth. (Some services like audio don't die easily.)

I've even gone as far as shutting down x (service gdm stop) and working entirely just from consoles, which let me stretch my netbook battery life to nearly 8 hours.

Here are a few ideas:

• Turn off WiFi and Bluetooth
• Reduce screen brightness
• Reduce desktop effects (System->Preferences->Appearance->Visual Effects->None)
• Use Hibernate rather than suspend power features (System->Preferences->Power Management->On Battery Power)

Improve Power Usage / Battery Life In Linux With TLP

I will Update my answer on Is there a power saving application similar to Jupiter?, please have a look

Apart from using Jupiter, I was using TLP and it helped a little. Plus, it is my advice to not use Wubi as it sometimes drains battery faster than the standard install.

Also, keeping your drivers updates and installing most stable proprietary drivers helps.

Anyway, to install TLP use this:

sudo add-apt-repository ppa:linrunner/tlp
sudo apt-get update
sudo apt-get install tlp tlp-rdw
sudo tlp start

As I tell with all my clients with laptops - if you have a laptop make sure you are properly discharging and recharging your battery. This greatly extends the life of your battery.

Ubuntu has some great power saving options (System > Preferences > Power Management) Which will allow you to setup functions to help save your batteries life while away from A/C

Other things to take into consideration - if you're not using Bluetooth or Networking turn off those services (some Vendors even include hardware buttons for this) Dimming your Laptop Display is also a good way to conserve battery power. Lastly straying away (when possible) from CPU/GPU intensive operations will help to conserve battery power.

EDIT:

Usually it is said that Lithium ion battery has no memory effect. I read that a lot of times in several different places and chose to believe in it and charge my notebook battery randomly. Don't know if that is the reason, but in two years I ended up with a lousy battery (doesn't last more then 10/20 minutes). On the other side, for my smartphone I almost only recharge when the battery is around 5%, and after two years I almost can't notice any difference in the battery state. I would say it is good luck with the phone, but then I stumble across this article. It is a Nature publication and though I haven't read it all, it says that lithium ion battery do present a memory effect. So be aware that it is relevant to spare your battery of unnecessary charge cicles.

In addition to dimming the display, turning off bluetooth, etc. I sometimes use the CPU Frequency Scaling Monitor to limit the power my processor cores use. You can add it to a panel by right-clicking on a panel, selecting Add to Panel, and finding it in the list.

You can use the terminal app called powertop to find out what is making the cpu "wake up". simply install by doing sudo apt-get install powertop and then run by doing sudo powertop

Ubuntu provides simple power management under System -> Preferences -> Power Management. From there, you can configure what happens when running on battery versus on AC power, including screen brightness and sleep/hibernate modes. Tweaking these settings can give you improved battery life without having to install or configure any extra packages.

Kubuntu has similar options in System Settings -> Advanced -> Power Management.