Regulated alternator and ACR

[brak]

So, my first outing today and engine ran well (knocking wood vigorously). However, it really seemed like my alternator was not charging the batteries much (voltage was shown to be 12.7v or so on the engine voltmeter). It was not enough to turn the ACR on and so house bank didn't get anything at all.
Engine battery is pretty new (right out of West Marine) and used essentially for one start - so it really should be pretty full.

Question is, I guess, how do I know that alternator is working at all? How do I know if the external regulator is not affecting it adversely? And what do I do now (except look for actual electrician, of course).