88 5.0 Electrical / Alternator Problem

[Ford]

Rolling along in my 88 5.0 last night and the battery started to discharge. The battery was completely dead by the time I got home (within a half hour).

Obviously my alternator was not charging the battery. I left a trickle charger on the battery over-night and recaharged the battery for testing the next day.

With the battery fully charged and the engine off my volt meter reads 12.7 volts at the battery. With the engine running (no other electrical load). At 1500 rpm the volt meter reads 14.5. At 2000 rpm with headlights on and A/C running on high the volt meter reads 14.4.

So everything is telling me the Alternator is working fine. Why would it stop charging last night while driving and now be working? I did notice while driving that the battery indicator flickered. Could this point to a short in a circuit? I've checked the fuse link between the Alternator and the Battery. I suppose it could be a faulty starter relay. Battery cables look good. Belt tension is fine. Maybe the 5.0 fairy fixed it while I slept.