I presume this is your rig.
You already have lots of good advice about your rig's 50 amp split phase main service vs your inverter's 30 amp single phase service. And others have already spoken about your rig's power profile.
The fact is that you don't have and probably can't afford enough battery and solar to run your whole rig on an inverter, BECAUSE running on an inverter means running on battery.
Let's start with your 3000 watt inverter. At full tilt boogie, delivering all 3000 watts, your inverter will draw 250 amps from your battery bank. Your 400 AH of Renology Batteries can deliver about 80% of rated capacity...or 320 AH. Pulling 250 amps from any battery will also reduce its rated capacity, because rated capacity is typically done at a 20 amp draw. But hypothetically, your inverter can inhale 78% of the battery bank in the first hour.
Use this calculator to do your math:
Watts/Volts/Amps/Ohms Calculator
Power is watts. Volts are always 12, because that's the nominal voltage of the battery bank.
So let's say you're going to microwave some raw potatoes so they are cooked. This takes about 10 minutes. Your micro will draw over 1000 watts continuously. So for 1/6th hour, your micro will pull at least 83 amps. So that one act alone will inhale about 14 AH from you available 320 AH in the battery bank. Now, think of running one air conditioner.
| 13,500 btu RV air conditioner | 2750 | 1250 |
| 15,000 btu RV air conditioner | 3500 | 1500 |
Forget startup. 1250 watts pulls 104 amps at 12 volts...continuously. 3 hours running just one small AC unit will eat your entire battery bank, and your solar can only produce about 1/3 of that on its best day.
Meanwhile, your 400 watts of solar, on its best day for the three hour period around noon can produce 5 AH/100 watts...or 20 AH/hour for +/- 3 hours (60 AH) and for the rest of the day, perhaps about another 60 AH. So your solar can push up to 120 AH into the battery bank on a sunny day in June when there's no shade on the panels. Late spring or early fall, those solar production numbers drop significantly.
Now another hard fact of life. I'm guessing your rig came through with a 12 volt compressor fridge...not an absorption fridge that can run on propane. Specs on a new one of these say you have a 16 cubic foot 12 volt compressor fridge. If you have a 12 volt compressor fridge, you're in for a rude awakening when it comes to 12 volt power. This is a huge fridge, and even the 10 or 11 cubic foot models eat a minimum of 35 AH/day...and in hot weather, and when getting lots of door opening/closing pumping action dumping the cold onto the floor, think more like 60 to 80 AH PER DAY!! Your solar is only making 120 on its best day.
What I'm describing is a consumption profile that can far outrun your battery and solar after you add in furnace time, lights, water pump, awning in and out, power front jacking and leveling jacks, slide, stereo, TV, and, and, and.
Getting to the point, your inverter is great for occasional use...say to nuke some popcorn when the generator is not running...or running 120 volt CPAP overnight. But you don't have anywhere near enough solar, and without it, you don't have anywhere near enough battery to be considering running your whole rig's electrical needs off an inverter.
Bottom line, you need a generator that can produce power adequate to support your 50 amp split phase demand, or a smaller generator that can do some but not all. The second you fire up even one AC, even a mid-sized (3000 to 4000 watts) generator will be working. Without a bigger generator...forget the inverter...you might not be able to run the microwave and one AC unit at the same time.
Your inverter has a place, but it's a MUCH smaller place in the power supply profile than you might think. If you are boondocking and you use it liberally, you'll be dead in the water in short order.
Use that calculator and learn more about solar and battery capacity and power consumption for 120 volt appliances. BTW, if a 120 volt appliance says it draws 5 amps at 120 volts, the hard truth is that the same appliance will draw 50 amps at 12 volts. The laws of physics are immutable. For your rig, the ideal generator would be a built-in Onan of 5000 watts or more. Regardless, given the size and character of youir rig, you're gonna need
