Like Turbs said, converters and inverters are different. Inverters use battery; don't charge them. You probably should update your signature line, so we can see what kind of RV you have.
You get what you pay for when buying an invert. Magnum is the Cadillac, but nothing wrong with Morningstar products. First thing to do is get a Trimetric battery monitor to see what you are using. You need to provide more information on what you are trying to accomplish... there is way too many variables.
If its solar you are seeking you need to study first. Here is a link to a guy that seems to know what he is talking about. I'm still trying to absorb what he has to say.