LS Focus battery light coming on.

[prydey]

Hi guys, late yesterday my wife got home from the local shops, with her focus sounding like a bus (whirring/humming sound) and the battery light on, on the dash. popped the bonnet, smelled sort of an electrical type smell but nothing major. noise seemed to be coming from alternator area but hard to pin point.

this morning, i went out and put the multi meter on the battery. over 12v and jumps to 13-14v when i started the car, so alternator appears to be charging.

the car also seems to have 'fixed' itself overnight. the noise is gone, and the battery light isn't illuminated.

any ideas as to a possible cause. unfortunately i didn't get the multimeter out last night when it was doing it, but i can't see the battery still being at those levels this morning if it the alternator hadn't been charging on the trip home from the shop (about 2km)

could it be a seized bearing or something, that freed itself up overnight?

thanks in advance for any help.