Sounds like it is designed to be used as an Emergency Power Source .
In my opinion not going to be able to power Your RV but may allow You to watch TV or operate/recharge Your Laptop.
Using a 12 Volt Inverted (120) Power source to then Convert 120 back into 12 is a waste of time and effort!
The Rule that I follow is 75-80 Watts of Solar will maintain 12 Volts of Battery at a 440 AH Rating (2X 6V Trojan T105 Batteries), assuming minimal usage and maximum Exposure to the Sun! ( Simple or no Controller)
We have 275 Watts on the roof which keeps Our 4X6 V Battery Bank Running 24/7/365 through a Morningstar 45 Controller.
We watch 4-6 Hours of Sat/DVD TV Daily and several FL and LED Lights, but do not even attempt to run Coffee Makers Etc.