General info on grid-tie and with battery backup

My small humble cabin in the woods is just about ready to be tied to the grid. Arrangements have been made with local co-op. Just waiting in line to get connected. My new service will be completely buried underground and out of the way. No trees requiring to be cut down or any land cleared out. Just soon as they set the meter, I will hopefully have all of my wire run underground ready to connect up.

I have a very modest solar array that has been working well for the last four years. It consists of 180ah 48 volt battery bank fed from 1800 watts of panels wired to work with a 30amp charge controller. Last week I picked up more panels that will add 3000 watts to my system. Then whatever else needed to connect everything. Just thinking things thru and trying to piece it together that will help out the overhead. I was considering a grid-tie or more likely a hybrid connection.

From my co-op:

• We will inspect to ensure a properly working UL 1741-compliant inverter. Requirements include:
  • A visible, lockable, and accessible solar A/C disconnect switch.
  • A label/notice indicating the presence of solar energy.

So aside from the inverter, I am free to do what I want on my side. This sounds affordable and simple enough. Except the expense of a UL 1741-compliant inverter. For my solar array, would likely go with the smallest one available. Assuming there is much in the way of choice. Power usage is very minor, except when operating my machine shop. So offsetting the constant small load that adds up over time and only relying on grid power for the most part when there is a higher demand.

All of my equipment is 3 phase, so a rotary converter is something else I have to work on. The shop is not something that is going to be used all of the time, so big power demands spinning the meter to an early death spiral is not likely.

Am I over simplifying all of this or missing something?

A 120 or 240 1ph to 240 3ph VFD is much cheaper & easier than a rotary converter. I've been using single phase power to drive 3ph motors starting with ParaJust & Minarik VFD drives in the late 1970's. They also function as a soft start as the acceleration can be adjusted.

I am in need of one to power up a 5 hp motor on the lathe. If the off brand VFD units are good, then I can do that. Otherwise I already have all of the necessary junk to build a rotary converter.

Spending over $1000 for a better VFD does not sound cheap. I have read these are mostly hp specific and not oversize or undersize the motor capacity to unit output. That would mean I have to buy several of these for each rated hp of any particular machine.

If the chinese cheap ones have proven reliable over time, I could afford to buy a couple of them. The thought of having to rewire the lathe motor is not something affordable if there is a melt down.