Since the past week or so, I've noticed my battery life has significantly decreased.

I used to get around 1 1/2 - 2 days battery life, where I'd use the phone normally, surf the web on 3G and things like that.

Now I'm lucky to get 4 hours battery life on 2G, my brightness all the way down, and I'd only turn the screen on the check the time or send a quick text, so the phone would be on standby with the screen off for a majority of this 4 hours.

I bought a new battery thinking my old one was dodgy, but the exact same thing happens.

I've also noticed that my phone is quite sluggish and apps are frequently crashing.

What could be the problem, and how could I fix it?

My guess there is a background task always running and stressing the CPU, slowly eating up your battery...
Did youinstall anything recently? Update anything? Tweak or hack anyzhing? I suggest you install "Conky" a system monitor, there you can check the actively running tasks and maybe draw conclusions from that.

it's a known issue. The usual culprit is the hildon-desktop and catorize. Remove/uninstall catorize from your n900, reboot it and you will notice an improvement.

I would, if I had catorize installed. But I dont...
And as pointed out, hildon-desktop hangs at 0.5 and not 5 percent, so that can't be it.

Install & run powertop for 10 mins and copy/paste the output. This tool should tell you if the phone is going into sleep mode (0V) properly or if it is spending too much time in non-idle states.

From observing my battery I realized that the more you fill rootfs the more faster the battery would drain Having something like 10-15% left on rootfs would indeed give you terrible battery life.

Also the program shortcutd did something to my devices battery life >_>. Ever since I installed it, my battery goes through leaps and bounds. One sec I'd have 87% battery life, I'd lock my screen for 3 mins or less and It drops down to 80% and thats without apps or wifi running. Uninstalling it helped, but It still drops like this from time to time, but like once every few days.

I don't know if the program messes with the battery indexing or anything. If anyone else is willing to test or testify to this that'll be great, just to make certain my prob wasn't caused by shortcutd.

Don't worry guys, I fixed it.

I installed Conky and saw the problem was that the Xorg process was constantly running at 97% or so.

The culprit was the 'Advanced Power Monitor' I had installed a while ago. It seems that even when you uninstall it, it doesn't remove all the files and a script it was running was causing Xorg to use all my CPU.

Thanks to the thread here --> http://talk.maemo.org/showthread.php?t=60588 I managed to save my N900.

Refer to this post on how to fix it:

http://talk.maemo.org/showpost.php?p...2&postcount=45

Note: You have to have rootsh installed and be logged in as root to run the command in Xterm.
(ie. type 'root' without the quotation marks before running the commands).

Then simply reboot and voila! Your N900 is saved!

Geez... I should've waited then... I got so annoyed yesterday I pulled the plug and did a complete reflash. I just started using the device so theres not much to say yet. But I guess the problem should be gone as my device is practically in factory state.
Thanks for the excellent suggestion though!

Edit: Guys, I'm a ******. I was participating in two different threads, in one I was discussing my own battery drain problem (~1% a minute even in standby, maxed out CPU with no apparent load, ...) and in this one I tried to help. I confused the two and took over this thread... *shame* I only wish MicroB would display the thread in its whole width, then I could use the appropriate emoteicon but it doesnt and I cant, so there we go again: *shame*