Quick reply...
When running, I carry, but don't use, N900.
I also carry and use a small thin cellular phone as stopwatch.
It will soon lose cellular functionality (I don't enjoy phones locked to provider), but it is still good as stopwatch.
It's not Android; it's simpler; maybe, kind of Symbian, judging by menu, menu and menu structure of options.
It has no sport tracker.
I suppose it can live through more than eight hours without a charger even with stopwatch running; it makes the screen black when you don't press buttons, and it can live days and probably weeks while connected to network and doing nothing.