Lithium system for larger RV, maybe?

Well, if you are creative and know what you are doing you can probably find a written off 2013 Smart ED. It has an 18 KWH battery on board. It is not that much bigger than what I'm looking at there. IT literally fits under the floor of the smart. For size reference, here is Angelas smart ED daily driver. After more than two years we are seeing about 1.8 percent degradation in the first year and another 1.4 percent in the year and a half since then. For someone that knows what they are doing it might be a fun project for a large motorhome. An 18 KW battery pack would be amazing.