Nice work vasilov. It’s been a full two days now that I’ve had my Nokia N900. I had a similar 6-hour battery performance experience (see my USAGE REPORT: My First 24-hours With the Nokia N900). I wrote another post on my usage of the phone today, and what I did to prolong battery life (it was at about 75% when I got home after work):

USAGE REPORT: 16 Tips for Prolonging Nokia N900 Battery Life

Best,

digittante

my experience, IMs drains a lot of power if left online. Shorten my batt life to half. Full Back light on consumes 3x power more than no back light. Using my e51 with power profiler from nokia.sorry if it's irrelevant

O.k., so all you have to do is disable all the features the n900 is all about? Funny!

Note: The battery performance will improve after several cycles. Many people have confirmed this already.

1st Charge Cycle: Dead @ 6hrs
2nd Charge Cycle: Dead @ 8hrs
3rd Charge Cycle: Dead @ 9hrs (7am-4pm) (0C / 32F Outside Temp.)
*I suspect that I would've gotten more if it wasn't so cold

Widgets: Media Player, Tunewiki, Omweather (4hr updates), Calendar, Conversation Inbox

Settings: Brightness 2/5, Silent Profile, Screen Vibrate on, WiFi on (100, Bluetooth off, GPS on, Availability online, Email routed thru Nokia Messaging

Usage: Moderate (across the board: Internet, email, sms, calls, video, etc)

I estimate that I should be able to get the time up to 16 hours after about 5-6 charge cycles, and by disabling widgets like omweather until their battery drain is improved). I'll find out for sure in the next few days.

Notes:
1. I have a feeling that GPS is a culprit, its always trying to update location.
2. Omweather widget may be a culprit (not confirmed)
3. Facebook widget determined to be a hog
4. Email via email provider caused some drain
5. Routing all email thru Nokia Messaging for less drain (live updates/push email)

after getting my device las wednesday and having a 6-7 hour battery life I'm starting my process of improving it. currently i have irssi on all the time which I assume eats alot of power. I'm gonna try running my phone with irssi off next cycle to see if there is an improvement. My friend lost only 15% of his charge last night using irssi over ssh instead of directly off of the phone. I'm guessing the constant ping pongs use the radio alot which drains battery.

If not having a unlimited data bundle it makes sense to set phone to use GSM only. When need for data transfer easy to change to GSM/UMTS.
3G Radio uses plenty of power. On my old E71 I could add one extra working day by using 2G. Seems to help also on N900. Before I get unlimited data I will keep phone in GSM/2G.

the battery problem is breaking my heart really, I just sold my N97 to get the N900, and I really thinking about going back to the N97, I know ill miss the browser, but what the use if I cant enjoy it much.

With regards to sim card, i still have my one2one (Tmobile before they changed to Tmobile) sim and the battery life i have causes me no problems with heavy use.

or just buy extra batteries? I fully charged mine earlier around 2pm
then i used everything from skype, frequent logging on line spend
30 mins playing game, 30 mins of music, too at least 8 photos
(uploaded some of them online)

.... less than 7 hrs later... battery died (take note that wi fi and/or
3G,3.5G is on the whole time. I like it that way, that's why I have 1
extra battery with me and might consider getting a other one.

is it true that the more I charge the battery the more power i will get?