If you are afraid of spending too much to face the LITHIUM system in your camper here is a solution with components useful for the purpose especially for vehicles that are not very recent. Enjoy
https://www.ippocamper.it/
https://www.dstek.it/shop/?gad_source=1&gclid=CjwKCAiAjeW6BhBAEiwAdKltMrVxmEZ5ZsWBeUEEZLt_ZAQXCaz5al2-YbPeBNxSOcjMNN5KJw1x9hoCV1cQAvD_BwE