The only way to use the converter to power the 12 volt side of the house is to make sure the batteries are disconnected from the 12 volt "house" loads, with only the converter powering the "house". It is quite inefficient, with a 10% loss at the inverter and as much as another 30% loss at the converter. It can be done--but it would not be wise to do so.
lawrosa wrote:
I also wonder that this invertor is 90% eff what are also the loses going into the convertor @ 120 and converting to 12v.
Since now that im plugging into the invertor the 12 stuff runs off the convertor and not off the batts directly I would assume?