http://blog.adl.pl/saving-n900-batte...ell-script/495

Saving N900 battery power with simple shell script

It’s not a secret that Nokia N900 is a real power sucker and needs quite frequent contact with battery charger, especially when all those fancy always-online features are enabled and in constant use. I keep my N900 in such mode nearly all the time myself, yet there are times (overnight, while at work, hospital etc.) where I’d like to sacrifice being online 24/7 in order to spare battery an extra breath. Offline mode is not an option, as I’d like to preserve ability to actually make voice calls and send text messages. You know, old-school.

So, thanks to great input which I’ve received on maemo-users mailing list and few additional sources, I’ve crafted a simple shell script called power-saver.sh that does few things in a single go:

1. Sets internet connection mode to “Always ask” (available under Settings -> Internet connections -> Connect automatically).
2. Disconnects current internet connection.
3. Switches cellular radio into 2G-only mode.
4. Disables automatic email send&receive in Modest email client.

While same script is used with “off” parameter, it re-enables automatic internet connection mode, dual (2G/3G) cellular radio mode and automatic email checking in Modest.

Simply speaking, basic usage is as follows:

root@n900:~# power-saver.sh
Going into power saving mode...

root@n900:~# power-saver.sh off
Restoring power suckers...

From my experience, actions taken by this script should make quite significant difference in battery life, yet YMMV of course. It also does nicely play with Alarmed application, so you can conveniently schedule power saving script to execute overnight and restore in the morning automagically.

Script is available for free download, use and any sorts of modification you’d like to make yourself. It’s simplistic shell script, no GUI whatsoever, so use it via X-Terminal. It could be wrapped up with some nice status-area button or something, yet my Maemo development skills (and time) are very limited.