Apologies, but I thought that's what you meant with your original test. I thought I was to connect the voltmeter to the ammeter while the car was running (and showing the problem) to see what voltage the ammeter was seeing. I'll try again today, and also try turning on some accessories. Actually, all I have to turn on are the lights...no fan, radio, etc. Haha.
I waited until the battery was fully charged before beginning any diagnostics. In fact, when my charger indicated the battery was fully charged/maintaining, I checked the battery with the voltmeter and it showed 16.6 volts. Could the charger have overcharged the battery? It's not exactly a high quality unit, just something I picked up from WallyWorld a few years back.