There is no path from the wall plug to the 12v system w/o going through the DC2DC converter (unless changed on the plaid). They can control how much goes into the HV battery by controlling the voltage on the main DC bus. But it still goes to HV DC first.But, the HV battery is not charging when the door is open. I get 3 or 4 amps of juice from the wall connector. You think that dribble is going to the HV battery and not the 12 volt? Why?