solar on/off grid installation

I realize the panels will not produce 120v. I was planning on having battery bank in the camper that is large enough to run lights, maybe charge a laptop, run a tv if possible, or a fan for a few days. I did not think about the power feeding back in the lines if there was a power failure if i use it as a tie in system. I was looking at purchasing a cheap 600 watt inverter to connect the solar system to my house outlet. I could put a switch to cut the panels from the camper and install a plug on the side of the camper, which could then send the 18v dc into an inverter and a relay in my garage. I am planning on buying an on/off grid system for my house within the next year, so buying some of the pieces now would not be a big deal. However, the system for my house will be around 5000 watts, so anything i buy now I will need to be able to handle a much larger system down the road. The tie in system could wait until i install the bigger system on my house, but I figured if the panels are working i might as well be using the power that is coming off of them, even if it is a small amount. Where i am located i can easily angle the panels true south with no obstructions. I appreciate the response and thanks for the link.