Its a common thing this coffee fix,......
Mounting an invertor so it has the shortest cable runs from battery and to appliance means you should get the most from your power, cable size is very important and you don't leave them turned on as they are still using power even if you haven't got something plugged in, if you are off grid you want your solar to charge your battery, running your car for a few hours to recharge isn't going to do your car or wallet much good.......
When Off Grid, how well your battery recharges all depends on what you run off it/them, my 100 amp may not charge as well as yours as no 2 set ups will work the same, too many unknown factors.
Have a couple of trips in your new van before you go spending $$$ on mods "you think you need", as often what you thought you needed isn't and better to get it right first time........... I have a 400w invertor for charging my laptop, camera,drill batteries,no coffee machine I use a plunger, many I have found use their genny, massive effort to get their coffee and all they often make is a hot coffee flavoured milk shake.....
The thing is Off Grid you want to keep your use of it to the coffee machine not TV's, toasters and such or you will have to up your battery storage, TVs run off 12v quite well along with many other things, most important what sort of fridge is fitted if its a compressor fridge you will need to add more storage and possibly panels.
Inverters can make caravanning easy, understanding how they work will ensure you buy the right one
www.withoutahitch.com.au
while it does advertise their products it does have some good info.........
https://www.mygenerator.com.au/blog...i-need-for-my-caravan-camping-off-grid-setup/