Demonstrated in the video are two applications that can indirectly improve your N900’s battery life.
Simple Brightness App
With the simple brightness app, you can keep your N900 on a low brightness for most operations and then quickly switch to full brightness for other tasks when required.
e.g. on a long train ride, I can keep the brightness on low. If I want to show someone something on the N900, I can switch to full brightness so they can see it better.
Although you can do this through phone settings, the brightness applet lets you alter brightness from the status bar, making it more feasible to change brightness often as it’s so easy to do so. [Brightness app is itself nice to have. It should really be there by default like on previous tablets]
3G/2G selection mode applet
Another app is 3G/2G selection mode applet. Also from the status bar, you can switch from Dual Mode to either 3G or 2G. Staying at 2G helps preserve battery life. This is most useful when you are in an area with poor 3G signal. At 2G you save on battery, but you’re still active with data (e.g. for email).
When you want to switch to a faster connection, you just select 3G. It takes about 3 seconds and signal/network dependent, you’re browsing at 3G/3.5G speeds.
See video for demonstration of this app.
To download, you may need extras testing apps catalogue for App Manager. See here on how to install that catalogue