I had a portable 100W "suitcase" system I got when we had a travel trailer and now use it to keep the batteries charged when our motorhome is in storage.
https://www.amazon.com/gp/product/B00MGLIIQO/ref=oh_aui_search_detailpage?ie=UTF8&psc=1
I bought a couple of mid-price jumper cables are from Walmart and spliced them together - battery clamps at one end and a 12V plug connector at the other. I cut the battery clamps off of the solar panel controller output wiring and put in another connector. I might get some ring connectors an put in a semi-permanent plug in at the battery end too.I also use this cable to power my portable macerator pump that I use to dump tanks at home.
https://www.amazon.com/gp/product/B00JZR3IEO/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1
I lay the solar unit flat on the ground behind the motorhome (I'm parked basically E-W in the storage site I rent and this gives me sun most of the day) The jumper cables are run along the side of the motohome to the battery compartment (We have an ACE 30.1, so its behind the front driver's side wheel). The panels are laid flat so they won't get picked up by heavy wind. I'm backed up to a spot on the boundary, so the panels are pretty well hidden. I doubt they will get legs, but you never know. Our lot is limited access and video monitored and the owner is there every day.
This keeps the batteries charged (I have 2 6V batteries, but will be going to 4). The controller that came with the system is holding 13.1 volts on the batteries
I plan to install at least 200W of solar on the motorhome roof sometime this year, and probably will add another 200W next year. I'll use a MPPT controller so I can series all of the panels and keep the wire size down to the controller.
