Sounds like a nice setup! I find the AC side is more difficult than the DC side.
I did an interesting load test yesterday. Since the MPP' supply PV power to loads along with the batteries, I wanted to see what battery alone would do with 2 LV6548's in parallel( one per phase, but not in split mode yet). So I switched off the PV input, and tried to put enough load on the units via battery only to shut them down.
This setup is only connected to my barn, which is my workshop, but has an apt on top. So I turned on all the lights, a heater, the air conditioner, the TV, fridge, all my chargers, my nail gun compressor, ans my dewalt table and chop saws. The fans spun faster, but I could not bring them to their knees. I guess I dont have over 13KW of stuff in the barn.
It was nice to see that those Lifepo4's with the Heltec BMS worked well, and the MPP LV6548's shrugged off the load.
Next test is to finally get the units in split phase, and then add in my 240V Arc welder at the same time.
So far so good! I am top balancing the second bank of cells now, so will have 28KW of battery when done. As soon as I get my shipment from Michael, I will need to redo all my batteries onto a shelf like Andy in off grid garage, as that will add two more 16s banks for a total of 64 cells. Damn this is fun!
As this is proving out really well, I will be repeating the process for the house I just bought in Charleston SC, and removing the existing 13 year old SMA Grid Tie sunny boys with MPP.