Hi, I just registered here - I didn't have any problems with my Nexus One until a few days ago when my battery died much too early a couple of days in a row. I recharged a few times 'from 0 to 100' and the last two days the drain wasn't as bad.
Now I am on a quiet spot and hear this phone clicking - very softly - and the clicking only goes away when I switch it on. 'Airplane mode' lowers the frequency of the clicking but even then it's not gone. Reboot doesn't change anything and I wonder if that clicking is/was connected with the low battery life.

Does anybody here have an idea what that might be?

PS low battery life - I mean it held up over the day - in the evening it would be maybe a third and over night it went dead. So that's good for people playing around/using/phoning/mailing a lot, but I don't always and certainly didn't have the phone in action a lot over these couple of days I now observed.