well i guess thats why Nokia gave us a free DC-11 when i got the phone. It helps to have a battery handy. I did get another battery (compatible) that works great with my 5800 but when i use it with the N900 it DOESNT EVEN BOOT UP!!

Well but in reality the battery levels are really unstable. sometimes even doing the same activities day in day out, SMS, calls, mail check (thru Wifi) it doesnt give the same results.