You'll need to do an energy audit of your power requirements and the duration you expect.
Then you'll need to insure your batteries are up to that task. Then size your inverter appropriately.
Many RV'rs load-shift in this manner. Everyone has different requirement.
Many users will recommend Magnum Energy inverters for numerous reasons.
Your inverter needs to mounted as close to your battery bank as practical due to the cabling requirements.
J & J
+ Kickr's the Vonderhund
, ES-38RSSA, 19.6K#
, 3500HD-Max, CC, 8'-DRW, 9.1K#