anytime you're down to one of anything its a PAN
Fully agree with the guys posting above stating they'd call a PAN. So would I. I recall a couple of incidents in my previous employer.
However, while I was in flight school, one day I had an alternator failure. I remember I told my CFI that since we were down to the Batt, shouldn't we call for urgency? He said "well, that's not going to do much for us right now."
How does one reacts to an alternator failure in a single engine?
Best regards