Should a car's battery voltage ever drop below 14 while running? If I let my Gen3 Teg sit at idle with the headlights, rear defroster, ac running, fan on high the voltage drops to around ~13. If I even tap the pedal the voltage is back at ~14.4.

The battery is brand new and they tested the alt at advanced auto parts and said it was fine- should I get another opinion or is this normal?

 

The alternator isnt running full potential at idle.