[Jack Houpe]

If your magnum is unopened try and return it, Growatt is all in one, a 6kw 220vac inverter, solar charger, battery charger when plugged into the grid and cost $1299 from Signature solar. Also you can buy the wifi dongle ($50) and you can monitor batteries, inverter and solar panels from anywhere in the world from your phone. If you where to go with a 24 or 48vdc system you can still power the coach with a 24-48vDC to 12vDC converter this will make all your wire sized much smaller if you go with 24 or 48v. If you want to keep the magnum then you will have to purchase a MPPT solar charger and another DC to DC converter to charge the lithium batteries from the alternator, lithium batteries have different charge characteristics and you just can't charge them from an alternator. 

On lithium battery subject, almost all the lithium batteries are made in China, if you buy a battery made in USA it more than likely has China batteries in it. I buy Calb batteries, they are made for aircraft and have a heavy duty case around them. Here is a picture of a battery I built for our Airstream Interstate when we owned it.

I will be doing the above down the road but now we are involved with a major project rebuilding the salon slide.