For some time now the charging of my batteries while in my N800 has been flakey. I was hoping that the problem was my ac adaptor or maybe the plug. After trying several different ac adaptors, a dc adaptor and several different batteries I am convinced that the internal charging hardware has malfunctioned. Not really a problem though. I keep a spare battery in a charger at work and a spare battery in a charger at home. I set my brightness to 50% and set my display to turn off after 5 minutes of inactivity. Most days I go all day on one battery. I actually have 4 batteries in all.

that sucks. good thing you have external chargers. i didn't know such a thing existed for an n800 battery.

This is just one example of a desk charger for a BP-5L battery:

http://cgi.ebay.com/Desktop-CHARGER-...3A1%7C294%3A50

also had problems like this. my first original nokia charger was VERY sensitiv to every little motion, often nokia stopped charging and had to be touched softly to recognize that the charger is still plugged in. once it stopped working at all. bought new one and problems are fewer but still present.