Dave Plowman wrote:

wonder just how hard an alternator charges a battery after a cold
start. In amps - given virtually no car has an ammeter these days.

They may not have an ammeter on the dashboard, but they do have one on
the CAN bus.

http://lh5.ggpht.com/_lF5XJ5xAktU/TOSPHKoUU4I/AAAAAAAAABg/mRTCnyRQk8E/s800/vcds_battery.jpg