Read this thread too... -
Here's what I put on that thread as well. Working great for me...a bit different as i didnt have an inverter already, but should work for you too...trick is to make sure your converter isnt also running / trying to charge your batteries when your inverter is running basically.
Put a 30amp (or 50) outlet near where you plan to install your inverter - and power this new outlet from your inverter...you should have lugs on the inverter to allow you to hard wire this new outlet.
Plug your motorhome into this new outlet such that when you turn on your inverter your entire motorhome/ trailer is powered by the inverter. IF you do this, you need to do a few other steps...
1. Make sure your fridge is on propane only, not auto -otherwise your fridge will be powered by the inverter. Make sure no other high powered devices are being used, unless expected of course (coffee maker), compressor, etc. Worst case inverter will shut off but wont harm it...i have a renogy 1000w and it just turns off for a few minutes.
2. This one sounds tricky -and if you google it enough you'll find it...Since you're entire motorhome in plugged into this new outlet (running off the inverter now) - it thinks it's plugged into shore power and a a result your converter starts up / thus trying to charge your batteries...You don't want that to happen of course - meaning, you dont want to charge your batteries while you're using them...double usage. You can stop this by installing a relay - and activating that relay when your inverter turns on...you should also have a normal 3 prong house style outlet on your new inverter, use it to do this...and tap into where your converter gets it 120v power from - such that when your inverter is on, it turns off power to the converters outlet. All of this can be done with a more expensive unit that's an all-in-one -but this is the cheapest way to do it and allows all outlets in your motorhome run on a inverter. Anyway, hope this helps - i did this last year...pretty tweeker, but its easy to do...and only cost ~ 100 bucks for all the parts.
Watch this: