I have a 2004 F150 4wd (185,000 miles), with the battery light on in the second startup of the day. It does not light up on the first start up. I replaced the alternator several months ago, and now this light thing has shown up. Gauge indicates that the alternator is charging, and the battery is several years old, and starting the truck fine. No codes on the OBD. Any suggestions?

 

A good part of the time when the charging lite comes on and the alt is charging fine , problems within the alt were the cause.