Very common installation in an RV. There will be lots of info on those sites with installation instructions. The distributors and manufacturers also have installation instructions posted.

I would put it in the rear side panel, somewhere with easy access to the battery. Mount it inside the compartment, considering cooling air flow. It will have a female receptacle. Mount a marine or 120 volt receptacle in a removable side panel, and make up a pigtail that just plugs into the inverter receptacle to power up the remote receptacle.

And I wouldn't use it much with the engine off, even though it will have a low battery warning built in.

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2007 X3 3.0si, 6 MT, Premium, White

Retired:
2008 535i, 6 MT, M Sport, Premium, Space Grey
2003 X5 3.0 Steptronic, Premium, Titanium Silver
2002 325xi 5 MT, Steel Grey
2004 Z4 3.0 Premium, Sport, SMG, Maldives Blue