What @rjsurfer said.
I came across a youtube video of a guy who set up to do that, but he was running a 5,000 btu, energy star AC, not the 13,500 btu unit on your camper. He did it with 600 watts of solar JUST FOR THE AC, 1100 watts to run everything else he wanted to run, and several Lithium Iron Phosphate batteries. Unless you downsize your AC, you are going to need a minimum of 2,000 watts of solar, and a dozen or so of those lithium batteries. Merely buying another flooded cell lead-acid deep cycle battery isn't going to do anything useful for you.