Hi chuck3,
I'm not comfortable with LI. They are unforgiving in the extreme.
Vandwelling is demanding on the vehicle and all the systems in it.
Are you building a unit from the ground up?
If there is any chance of below freezing charging being needed then LI becomes even more complicated.
The only information from end users is anecdotal. What seems to be happening is about a 10% loss of capacity over a three year time frame.
1.8 kwh per day is stingy use of power. I could not do that in my class C which has 556 amp-hours with 50% usable. That is 3.33 kwh. I find that is not adequate to my needs. I do have 256 watts of solar--600 would be a better number, but at the time I installed costs were $5 per watt plus installation costs. It was fine as a part time--but for full time 600 to 1000 would be more realistic.