I'm by no means an expert but I have some anecdotal information. As a lad it was commonly preached that a good way to check for a bad alternator was to pull a battery cable just as Sixtyfive did. I remember that being done on occasion. Also, although big trucks may be different, on last season's Ice Road Truckers, one of the drivers lost his whole battery box, including the batteries, in the middle of nowhere and his truck ran fine until he shut it off & it wouldn't restart.
