I bought an electric cooler to use with my camper, and later realized it works on 12v also, so I figured I'd try to make it work all the time. I've searched, but a lot of the builds were way more serious than I needed. I don't plan on adding a 2nd battery (unless it's required?), and I don't have plans to add any other powered items (no RTT, no ARB inflater or anything like that). Is there a basic, dummy-level list of parts I need to make it work?