Can I use the AC200MAX to run my tiny house completely off grid 365 days a year? 24/7 powered with solar panels of course?
It could assuming your power requirements are within the output capacity of AC200Max. Keep in mind that you also need solar capacity in the qty required by your usage. The sun does not shine for 24 hours or for 365 days a year (storms and overcast) and this requires a large battery capacity as well. It totally depends on how much power you would be consuming, how much battery capacity you need to maintain that power during nights and times of poor sunlight and sufficient solar capacity to recharge the batteries before they are depleted.
And to build on what Scott said. It all depends on how much power is required to satisfy your needs. Think of it as a water tank, If your tiny home doesn’t have water piped right in and you will be using a small tank to supply your needs can you get away with a tiny tank? (1 to 5 gallons) or would you need something a little bigger (20 gallons). The AC 200 puts out 2000 watts maximum, at that output the battery would last less than 1 hour. I think an AC 200 with 1 or 2 expansion batteries would be good for a tiny home, but I also think your power needs would have to be a little on the lower side. Lights are usually not a problem with modern LEDs but you have to consider everything. AC unit? Electric stove? Probably not.
Need to workout how much power you consume on a daily basis and build in a safety margin for winter or cloudy days. Additional battery storage and over panelling can help but be realistic.