Seeking off grid system build advice

[CRBROG]

I'm wanting to have a solar system for off grid living. I've already acquired 21 solar panels at 190w each, and a grid tie inverter. I know I'm still needing a hybrid inverter 3-5kw range, and a lipo4 battery bank.
I was looking to see if I might get some advice on the system setup. First off the grid tie inverter is an ABB 4.2kw,
model# PVI-4.2-OUTD-S-US-A
I've heard that a grid tie inverter is a good option to have in an off grid system. Providing efficient AC and being able to lighten the load of the hybrid inverter when panels are producing? The ABB inverter was included with the panels when purchased, so I just considered it a bonus if what I heard was true.
I was leaning towards a SPF 5000 ES
Growatt hybrid inverter, but didn't realize that it's 230V until the other day. Not sure if it would be worth the extra time and money to make it 110V, or just go with a different inverter?
I'm wanting to be able to run a small 115V mini split, mostly in the summer. 1 maybe 2 RV refridgerators to run ac in the summer, and propane in the winter.

The battery bank I was thinking would be a 48V lifepo4, consisting of four 12V 100ah 1280wh dr prepare power max batteries.
I also thought of going with a diy battery bank similar to the 280ah 12V bank built by Freely Roaming on youtube. Just adding more batteries to achieve 48V, and 400ah+.
I've also got a hydrogen appliances wind turbine that I will want to feed into the system too. Its a 12V DC turbine, that I'm contemplating the 48V DC upgrade.
I'm not an expert, but not the first time I've built a off grid solar system either. Any ideas thoughts advice etc would be greatly appreciated. Thanks

 

[BentleyJ]

When a grid-tie inverter is used with an off-grid battery inverter the configuration is called AC coupling. The off-grid inverter in this case is also known as a grid-forming inverter and it has to be UL1741SA compliant so it can control the output of the grid-tie inverters using frequency modulation. Without this feature there is no way to reduce output of the grid-tie inverter when the total household load, including battery charging, is using less then PV output.
The alternative is you would have to set up some kind of automated system to divert excess PV production to a dump load like a water heater.

 

[CRBROG]

When a grid-tie inverter is used with an off-grid battery inverter the configuration is called AC coupling. The off-grid inverter in this case is also known as a grid-forming inverter and it has to be UL1741SA compliant so it can control the output of the grid-tie inverters using frequency modulation. Without this feature there is no way to reduce output of the grid-tie inverter when the total household load, including battery charging, is using less then PV output.
The alternative is you would have to set up some kind of automated system to divert excess PV production to a dump load like a water heater.

Much appreciated!
Do you happen to have any recommendations on a grid forming inverter, or vendor?

 

[BentleyJ]

Do you happen to have any recommendations on a grid forming inverter, or vendor?

Schneider, Sol-Ark, Outback, SMA (Darfon, but I don't know much about that product) are the higher end, premium products that have the required functionality. I believe Growatt and possibly Deye have grid interactive inverters that can do sell back but not sure if they can AC couple. As you already mentioned, some inverters are single phase and would need an autotransformer to convert power to split phase. In my opinion this is an unnecessary extra piece of equipment when there are several choices of inverter that have split phase built in.

Regarding batteries, I would recommend using 48V batteries rather than putting 4 x 12V batteries in series. It just complicates things and adds extra connections which are sources of problems later if they loosen up or develop a high resistance and start getting hot.

 

[CRBROG]

Schneider, Sol-Ark, Outback, SMA (Darfon, but I don't know much about that product) are the higher end, premium products that have the required functionality. I believe Growatt and possibly Deye have grid interactive inverters that can do sell back but not sure if they can AC couple. As you already mentioned, some inverters are single phase and would need an autotransformer to convert power to split phase. In my opinion this is an unnecessary extra piece of equipment when there are several choices of inverter that have split phase built in.

Regarding batteries, I would recommend using 48V batteries rather than putting 4 x 12V batteries in series. It just complicates things and adds extra connections which are sources of problems later if they loosen up or develop a high resistance and start getting hot.

Great advice! Thanks again for sharing your knowledge. I think I'm going to build a 48v battery buying 16 EV LF280 3.2V 280ah cells from docan's Jenny Wu. So much to learn...