You are correct Enyibinakata -

Both me & my co-worker's phone uses 3G connection to retrieve email messages every 30 minutes.
Both phones has BT off and WiFi off (no free WiFi at work ).
I have received 3 phone calles today which last about 15 minutes together, my co worker only 2, which last 10 minutes.

My phone was almost out of use except for the email checking and occasonal checking for the time (by unlocking screen), while my co worker's phone was used with different apps for total of, a rough estimate, 40 minutes for the entire day.

I hope that you see this response as more reasenable & rational, but I deeply dought it will help me improve battery life whatsoever.

Anyway, I'm glad for you this has not been your experience with the n900 device.

Mine either. I use my N900 heavily for email, web and phone every day. For the hardware it's running, I think battery life is very reasonable. Very approximately speaking, at least on par with an iPhone 3GS and definitely better than the G1 it replaced.

As you said, user settings have a major impact on battery life. Also, location and coverage is a huge factor. If the signal is weak or intermittent, it will use up a lot of battery constantly searching for a signal lock. Because of these factors, meaningful battery life comparisons in ordinary use are hard to make unless settings are exactly the same and units compared have equally strong signals, preferably on the same provider.

Which makes my statement above comparing the N900, iPhone and G1 fairly worthless...except I have extensive experience with both the N900 and G1 in the same conditions and on T-Mobile. Limited iPhone experience. So take any such comparisons - including mine - with a grain of salt.

I got mine a couple of days ago, on the second battery cycle with 3g connected, fluffing around customizing it and checking a few emails I got 10 hours...can only get better too, although I doubt it will best the4 days I got out of the n95 24/7!!!!

Pretty sure Nokia will release a bigger battery at some point if this continues to be a major issue - which I am sure it will for many.

People shouldn't complain about how thick it is...did you look at the phone before you bought it?

I usually get 24-30 hours with wifi basically always on, aside from a couple of hours where I'm out and about without wifi access.

OK, here's how my N900 fared today, with a standard 1320mAh battery:

things always on:
screen at 40% brightness
connected to WLAN, if available
connected to GSM/GPRS/3G where available
photo changing widget (every 5 minutes)
weather updated on the hour
RSS updated on every half hour
Mail for Exchange always in online mode
one IMAP account always active (different from MfE one)
application updates always on
no screen vibration, no screen or system sounds

6am:
off the charger, battery 100%
checked for application updates
installed 2-3 applications
mucked around a bit, dismissing e-mail alerts
read an ebook for around quarter of an hour

8am:
disconnect from WLAN, connect to 3G
during the journey to work a LOT of reselections between 2G/3G, etc
connect half a dozen IMs, with GPS on as well
Bluetooth on, connect stereo headset
Start music playback
until next time check below did the following:
music on all the time
watched a short film (~10minutes)
read and replied to a couple of e-mails
read an ebook for around 10 minutes or so
tracked a bus journey using Maep for around 15 minutes

9.15am:
stop music playback
disconnect IMs and GPS
Bluetooth off
connect to office WLAN, disconnect from 3G
check for application updates
install 2 applications, remove 1
dismiss half a dozen e-mail notifications
a 5 minute phone call
muck around with settings
spend 15 minutes looking for battery level widget
muck around with battery level widget

11:30am:
battery at 36%

Now, if I continued this usage pattern, I could expect total battery life of at least 8.5 hours. I know this doesn't sound much, but if you look at what was happening (WLAN on most of the time, almost 1.5 hours music/video playback, screen on a lot), that's actually not too bad I think. When my E71 was a new kid on the block and I used to play with it a LOT, the battery never lasted more than a day (usually around 16 hours, with listening to music, WLAN, installing lots of apps, reading/writing mails, etc). These days, when I have N900 to play with, my E71 can last almost a week, as I use it for SMS and an odd phone call.

So, in conclusion, 6h battery life definitely warrants a query with the shop, or an honest appraisal of usage patterns.

Oh, and remember that E71 comes with a larger capacity battery to start with, 1500mAh v 1320mAh in N900, has screen half the size of N900, and runs an OS (S60) that has been optimised for power consumption for a much longer time than Maemo.

a tip for batteries is to totally flatten then totally recharge it 3 times, this does make any battery hold its charge better, trouble is battery technology cant keep up with phone technology, should nokia not have developed the n900 just cos theres no battery currently available to give people 48hrs standby time? i think not, personally i would have still bought the device if charge only lasted for 1 hour, you all have the latest technology in your hand, be happy about it!

A quick update to my previous post.

In the three hours after last time check I used the phone to dismiss a dozen e-mail alerts (i.e. not a lot), and then to (again) check for app updates, and instal around half a dozen (~3MB download). The battery level went down by 10% in that time, giving an approximate idle battery life of at least 30 hours, and that's connected to WLAN, and doing all the stuff it always does in the background (see the top of my previous post).

I'm happy.

with my n900 i would say i get roughly 1 and a half days battery life averagely, however it varies, sometimes it does 8 hours then its nearly dead, then other days it gives me more than 2 days.

3g for me is always on, i connect to wifi manually.

How can anyone use the N900 at 40% brightness? Seems too dim even at 80%. Current UI for N900 does not graduate brightness very well, so either it is real bright or not bright enough- just with a tap down to 80%.

Not a defective unit for me, since the other two I had showed the same issue.

40% is just right for me, 20% is too low though, I believe this is subjective everyone has different preferences....