Spoke too soon. Today when I started the X-5 the alternator never charged during a 25 minute trip running an errand. Watched the voltage at start drop from 11.9 to 11.2 during the trip with no red battery light - which tested OK during when ignition was turned on. Shut engine down, did my business and restarted. Alternator immediately started charging at 13.5 volts. Red battery light tests good, but did not come. I don't know if this is normal behavior or not????
2002 BMW 330i E46
2006 BMW X-5, 4.4i N62 engine E53