Point 1: thanks - I mistakenly thought that was communicated through some sort of intelligence like on many notebooks.

Point 2: That seems to be the wrong way to keep Li-Ion at peak performance. If that behaviour is correct - it is actually decremental for battery life.

Normal Li-Ion chemistry dictates you should not full charge the battery on every charge since you will be destroying cells. You should not start charging unless battery is LESS than fx. 92-93% - but N900 starts charging at about 1208ma - less than 2.5% less than design capacity and less than 1.1% from peak charge level.

But why the N900 cant run on charger power I do not understand. Charge the battery - then run on USB the charger power until disconnected?