Matt,
It does not provide backup, but it does provide power from the PVs (without a battery bank) which I don't see often. It's great to see more and more grid tie systems with backup. Most of the existing systems I have seen do not have it.
It seems grid tie with backup might be nice for certain types of RVing, especially when the RV is not in use or when on a metered camp site.
I could picture using it with my RV PVs at the house when I don't need them for charging the camper batteries. I have the panels and battery here and a cheap grid tie system hooked to a load dump on a solar controller to tap those unused watts is tempting. It only makes economic sense if the grid tie unit is very inexpensive though, otherwise the payback is too long to justify the purchase.
Jim
