Vibrant93,
You've been given some good info. You have stated that see no more than 12.2 on the house battery side. May I ask, WHERE are you seeing this reading? Is it on a panel for checking the house battery voltage? Or, are you reading it with a VOM at the house batteries posts?
gemert and Don have both indicated that you "should" see 13.8 at the output of the Converter/Charger. Well, something's obviously not correct here. How are your lights in the coach, with no shore power attached and, with shore power attached? Are they any brighter with the shore power attached?
If you take a reading at the house battery posts with the shore power disconnected, then take another reading across those same posts, WITH the shore power connected, is there any difference? How much is any?
Yes, if you have a Converter/Charger, it is wired and setup to not only supply a charge to those house batteries but, also supply 12V to all your house appliances if and when, you are plugged into shore power.
If you run the tests that have been suggested, and, you see no difference in the voltage across the battery posts, then you potentially more than one issue.
1. As you suspect in your original post, you have a problem with the output side of the charger side of your converter.
2. You have a breakdown in the line(s) from the charger to the batteries.
3. You may have a bad cable, cable connection, set of cable connections, loose terminal, ????
It will interesting to find out just what your issue is. Keep us posted.
Scott
Scott and Karla SDFD RETIRED2004 Itasca Horizon, 36GD Slate Blue 330 CAT
2011 GMC Sierra 1500 Ext Cab 4x4 Toad
2008 Caliente Red LVL II GL 1800 Goldwing KI60ND