I finally found a single setting in the n900 that seriously increased my battery life.

Since i got my n900, i had to live with the phone being completly drained after a maximum of 12 hours. 2 days a go i went on a road trip for a couple of hours.. and surprisingly my phone only lasted 6hours that day, even though i limited my self from using it to much!
That made me think, why would traveling drain my battery faster, and then it hit me... it had something to do with my phone switching between 2.5 and 3G/3.5.
My cell provider dosen't have full 3G coverage in my country, so even when i'm not travelling, my phone jumps between 2.5 and 3G all the time.

So after thinking about it, i went into phone settings and set it to gsm only... 12 hours of unlimited usage (fm transmitter playing music and surfing the web) and beeing on the road again couple of hours... i still had half battery according to the notification battery indicator. I can even be online in skype now all the time.

The questions is... why does it drain th battery having double network activated? Is it because when i'm on 2.5 my n900 goes crazy trying to find a 3G connection somewhere? or is it the switching between gsm and 3G it self that does it? Or does 3G just use alot of power compared to EDGE?

Hope this helps someone out there. Most of all, hope they find a bug with network switching, would love to use 3G again. but its just not worth it, when i can use my phone constently when i'm only on EDGE.

You changed Settings / Phone / Network mode to GSM right?

I noticed too that where I am the network is switching so I hope this is going to help my battery life a bit.

EDIT: I re-read your post and I got it. sorry

This helped me alot, so i'm sure its gonna have an impact on your n900 aswell.

I just hope someone can tell us if its the switching of networks that drains it and not the 3G it self. I'm concidering to switch cell provider over to 3. They only have 3G network in denmark, no gsm... so no network switching. But that wouldn't help much if 3G sucks battery like crazy.

Well, it's a (more or less) known fact that 3G sucks battery like crazy, even more so in areas with poor network coverage...
In fact, probably all phones which support 3G will have battery issues solved when switching back to EDGE...

So I'm not too surprised of your observation...but I agree that it may defeat the whole idea of always on-line (with a good network bandwidth).

Me too. fully charged 8am - dead by 3pm with very little use. Disconnected 3G and now baterry lasts X3/X4 more.

So glad not to be hampered by this affliction anymore. My mobile was almost not mobile at all having to take a charger everywhere.

merry xmas btw for all that celebrate it.

OTOH, why would you need to be always online "with a good bandwidth"? tasks that benefit from being always online (updating RSS, instant messaging, ...) don't require much bandwith in the first place... and if they run while the device is in your pocket, you wouldn't notice that they're slower than usual.

then when you plan to surf around or download something, you can switch back to 3G for a while (or maybe have wifi anyway).

so... yes, it could be a reasonable strategy to use 2G as default.

If this is so I think it would be a great idea to have a desktop widget/button to allow you to easily turn 3g on and off.

I second this.

I bought N900 without a data plan and if I understand correctly 3G helps you only if you connect to i'net through cell provider. 2.5G should be default. It would be great if Nokia solves this problem as I was planning to get a data plan.

Using GSM (Settings-Phone-GSM) increases battery life a lot and GSM connection is enough for email and IM. I use it now as much as possible and change to 3G only for internet browsing.

A quick desktop widget to change the network type would be most wellcome.

Defintely need a desktop widget to switch, but to be honest, why shouldn't these phones be optimised for 3G? My N97 was pretty good. I think its worse when you're in a weak 3G signal area like mine. The phone will boost its power to search for a 3G signal and then revert to 2G. It will constantly be checking for a 3G signal even when on 2G unless the GSM only is selected from options.