I am going out in space. The clunking may be a solenoid that connects 2, separate battery banks together.
I would be tracing out cables and searching thru diagrams
Why not ask the ones who are really doing it.
Rv Sue http://rvsueandcrew.net/
Interstellar Ochard http://www.interstellarorchard.com/
And while you are at it, do a web search for Solo Rv'ers or seek the Solo groups
The biggest problem, most of the roads you will be on - DO NOT HAVE CELL TOWERS.
Only the mayor cities do, and I mean Mayor. On the Cassiar Highway there are NO cell towers.
We purchase a burner SIM card. Not once did we use it.