Originally Posted by melvin2345
In our case, however, it's the Keurig. This last trip was the last one with the current one we have. Using it drew 135amps for about 2 minutes while it warmed up the water. Maybe 1/4 of that for each subsequent cup. They make models that use half that now, so that is one change we will be making.
135 amps for 2 minutes = 135AH/30 = Just 4.5AH usage from your batteries. Don't worry about it!
As mentioned, you've got 400w of solar which on a sunny day can produce up to 80-120AH of charge back into your batteries. With what you described, I would think that you will use somewhere between 40-100AH per day boondocking (especially if you don't run your inverter 24/7). Your furnace might use half of that power, so if it's not cold at night you will use much less than 100AH/day. And you always have your generator as your safety net if needed for 1-2 hours.
I think you should boondock 4-5 more times and keep an eye on your battery highs and lows for the day. Then you will have your answer.
As a reference point: I have purchased a few 30' class C RVs from Cruise America from their rental fleet. They send out 1000s of families every year in their RVs for all sorts of vacations. Many of those people must be boondocking from time to time. These RV rentals come with ONE lead acid AGM battery which has about 100AH capacity and no solar (...except for a 10w trickle charge solar panel which is really more for when the RV is just sitting on their rental lot between renters). So most people who rent/use RVs have just the 1 battery and no real solar. You've got ~240AH of batteries AND 400w which is about enough to charge your batteries ~100AH/day as long as it's sunny.
My guess is that with your current setup and your current usage, 95% of the time when you are boondocking you will be perfectly fine. So is adding more solar panels (~$300-$500) and batteries ($300-$400) worth covering a problem that only comes up 5% of the time (....and when it does, you have a ~$4000 generator backup already to get you through)?
I think a better use of that $$$ would be to buy something for camping that makes your wife's camping experience more enjoyable (...so that you can go camping more! lol).