Ok so after testing the univolt on shore power everything seems to be working both 12v
and 110v with no batteries hooked up yet.
I had a brief bit of confusion when the gfi on my house kept tripping but later I figured out that the cause was running 20 incandescent bulbs and the fridge and occasionally running a power drill off the various 110 outlets.
If I keep down the lighting the gfi doesn't trip.
Unfortunately I found out that my fridge works but doesn't actually get cold enough to be of much use.
If it's not one thing it's another.