Re: N900 battery discharges very quickly: small rant about rare but sharply annoying problem
 

@jaanusa,

It's not always software that drains the battery. I've noticed a couple of times that the battery starts draining (much) faster than usual although nothing heavy is running.

Normally (although it rarely happens) I just turn it off and on again, because I have no time to investigate.

The other day I had that again and, suspecting a WLAN fvck up, did (as root) rmmod wl12xx. The temperature went down and the battery consumption "flattened" again.

From my (little) experience this may happen when you get out of each of a WLAN AP, but that's just a guess..

Re: N900 battery discharges very quickly: small rant about rare but sharply annoying problem
 

I suffered this problem very seldom, about 10 times since I got my N900 in Feb 1, 2010.
I used always the standard kernel with all official fixes.
The last time it happened I used the KP50 kernel.

I say from careful observation:

1. it is not a software (app) problem, though it may be triggered by some kind of usecase with 3G data and GPS at the same time.
"top" shows no process going wild, when the fast energy loss is in progress. This is not a Maemo/app process problem!

2. on the N900 there are much more (embedded) processor cores than just the main ARM CPU. My guess is, some of those cores which serve the 3G/UMTS radio (phone) or GPS or audio codecs or whatever crash, or run endless loops, which will not show up in the Maemo-Linux process tools.
Or even some hardware has an internal, temporary shortage. Yes this is possible, but it all this is impossible to track down on a living N900, and one would need very expensive test equipment to analyze it. No luck.

3. If you note that battery indicators (I use Battery Eye) drop fast, reboot the phone immediately, after reboot the problem will be gone - until the next time...

Re: N900 battery discharges very quickly: small rant about rare but sharply annoying problem
 

I had something like this not long ago.
It wasn't a process but powertop showed loads of wakeups.
http://talk.maemo.org/showthread.php?t=85701

Re: N900 battery discharges very quickly: small rant about rare but sharply annoying problem
 

Seems that battery drain period is over, battery lasts with one charging again couple of days (phone calls mostly).
During "draining period" I even switched phone during night to offline mode but nevertheless battery was almost completely drained in eight hours. Although I noticed that phone charged better by using USB cable connected to computer rather than by using Nokia's original charger.

Re: N900 battery discharges very quickly: small rant about rare but sharply annoying problem
 

AFAIK, battery patch may cause strange problems http://talk.maemo.org/showthread.php?t=81358, posts starting from #5