Thanks Hugo.

I've seen this behaviour with varying degrees with my HTC Dream (G1), HTC Kaiser (TyTN II), Nokia E61, Treo 650 and Treo 600 definitely. Can't really remember about earlier phones of the non-smart type (6310i, T28, 8210, T10).

I wonder whether it'll happen with my Nexus One. I also wonder whether it will actually ever arrive, 25 days after I ordered it and its still 'on its way'.

Anyway, what I usually see when the phone is left on is that the charge will complete to 100% (or sometimes ~99% on the Treos or the horrible Windows Mobile phone) overnight. But the charge just seems to run down faster. As if there is less mAh per % of charge. I guess it must be down to imperfect metering.

Thinking about it now, although I have experimented I have not seen this trait with laptops - its clear by your explanation that sensibly they behave like the Rio Karma.