Not charging at idle.

Does it die if left idling for too long?

hmm, never had that happen , but it would take a really long time for that to occur, assuming a fully charged battery. I once drove my 66 charger with the alternator field wires unplugged, not very far but car got very sluggish, once home and tried to start it again it would not start, battery dead,, thats when I found the field wire had slipped off the alternator connection.