Ran across this Ford informational TSB this morning & thought I'd add it to this threads subject matter.
It's worth taking the time to read ALL of it, as there are thoughts concerning new & used lot vehicles about to be purchased, and their batteries condition that most of us wouldn't likely think about.
Also a heads up on Fords battery "eye" & what it's really for & what it can & can't tell us about the batteries condition & knowing that might prevent some of us from buying a new battery that isn't really needed, or falling for a high pressure battery salesmans pitch, using that battery eye as his selling point!!!!!
06-4-2***BATTERY SERVICE - OPERATION OF BATTERY EYE - CHARGING SERVICE TIPS