be thankful

This will help you optimize the battery life of your laptop so that it might actually reach the advertised specifications and maybe even a bit more. I’m assuming that you have a modern laptop with a SpeedStep (P3/P3-M/P4/P4-M/PM) or PowerNow(Athlon/XP/64)-capable CPU, but many of the suggestions will work even on older laptops.

First, let’s get the obvious out of the way:

1) Set your screen brightness as low as it can go before it becomes uncomfortable.

2) In your BIOS, set your power options to battery optimized/max battery/etc. (that is, if you have such an option).

3) Set your power options to battery optimized in Windows. Depending on the CPU that you have and the drivers that your manufacturer supplied with your laptop, there are different ways of doing this. You might have a Fn key that lets you change the power settings or an icon next to your clock that is something either specific to your laptop or a flag icon for Intel’s SpeedStep. In Windows XP, setting your power options to max battery in the control panel’s power management applet should also set the SpeedStep/PowerNow to its battery-optimized setting automatically. For older versions of Windows and AMD CPUs you can enabled battery-optimized mode by going to the AMD PowerNow tab in the control panel’s power options.

And now for the less obvious:

4) If you have discreet graphics (ATI Mobility Radeon, nVidia Geforce Go), underclocking the graphics chip will imrpove battery life. For ATI graphics, you can use ATITool and for nVidia graphics you can use RivaTuner, although you can of course choose any other tool (Omega drivers, PowerStrip, etc.) if you prefer.

5) Underclock and undervolt your CPU. Most laptops don’t have overclocking options so you need to use something like CPUMSR to do it in Windows. It’ll let you change the multiplier on any CPU but it won’t let you set it higher than the default (only lower). It also lets you change the core voltage, but you should be carefull as not to set it too low and thereby causing your system to crash. A note for people with Pentium Ms: CPUMSR seems to have a bug that detects Pentium Ms as Pentium 3s so you need to go to configuration and disable user protection. After this you can manually select Pentium M and change the multiplier/voltage there.

6) Disable all network connections that you aren’t using. This will usually disable the actual hardware and give you a few more minutes of battery life. Also disable your modem in the device manager (control panel > system > hardware > device manager) if you don’t use it.

7) Remove your optical drive. Replace it with a plastic blank if your laptop came with one. If you can’t remove it, disabling it in the device manager will probably also help.

In power options, set your hard disk turn-off timer to 3 minutes (the lowest).

9) Keep a conservative number of programs running. Fewer open programs and lower RAM usage will improve battery life.

10) As an elaboration to step 1), try a tool such as PowerStrip or the gamma tool that comes with Adobe Photoshop to increase your screen’s brightness and contrast via software. This will allow you to set the hardware brightness of your screen a bit lower but it’s not suitable if you’re doing anything more than typing/reading.

11) Your sound chip might also have a power-conservation mode. Check your control panel to see if your sound chip’s drivers came with any special applets that might have an option to enable it. Most SigmaTel chips have this.

There’s a good chance you can also use two batteries in your laptop. Check with your laptop’s manufacturer to see if they make a battery that can be swapped with the optical drive. If not, you can also buy a second main battery and swap them as needed while putting Windows into hibernation. Also regarding batteries, you should always allow them to fully dischage before recharging them. This will allow them to hold their full charge and it will reduce the memory effect (which still exists to a small extent with lithium-ion batteries).