Hi, I got my N900 phone's USB port broken and fixing it is too expensive in India (about 9000 INR). I am using this phone now with the help of external charger (China made) that costs just 100 INR and two additional original Nokia batteries.

This gave me an additional surprising benefit of increased battery life. Earlier it was struggling to last even a full day. But now, I am getting a life of a minimum of 50 hours

One thing I am making sure is to use the battery until it gets discharged completely (I could do it as I have spare battery to replace immediately).