3 phase sounds great but I am not familiar with using it so I would need electrician to repair all 3 phase equipment and or install. I do know 3 phase is much more efficient especially in those large load appliances. I am just not comfortable with 3 phase.
3-phase is distributed by the utility company, and two legs stepped down with transformers to 120/240V split phase (L1 and L2 each 120V and 180 degrees out of phase with each other for 240V) for residential neighborhoods.
Often apartment and condo complexes are fed 120/208Y 3-phase. Each unit is wired inside just like 120/240V but fed with L1 and L2 each 120V and 120 degrees out of phase with each other for 208V. A 240V heating element would draw 208/240 = 0.87 times as much current for 0.87^2 = 0.75 times as much power. A motor would draw 240/208 = 1.15 times as much current for same power. Most such appliances mention both voltages on nameplate.
The difference is you can wire 3-phase motors as well, and those perform better that split-phase motors.
And, you do NOT want to cause a short that draws an arc across all three exposed L1/L2/L3. Instead of self extinguishing in 1/120th of a second when voltage drops to zero, it can continue longer, causing a bad sunburn. Fed by 3-phase grid with near unlimited power, that can be severe plus cause an electric explosion. Inverter power of course is limited.
The reason I suggested 3-phase is that each Sunny Island cluster (with battery) is limited to 18kW or 24kW, but multiple can be ganged together to reach your 48kW goal. (A single split-phase or 3-phase cluster together with PV inverters could deliver 48kW and more while the sun shines, just not off battery.)
I have not thought about SMA but you also mentioned other brands. What models and pros and cons on those? I have seen videos on how good and reliable a product is but the programming is a nightmare. Software issues that shut down systems.
Other people here talk about software updates. I operate all my SMA equipment straight out of the box with the firmware that came from factory, never needed updates. Those are available, e.g. to connect a lithium BMS to a 15 year old inverter which predates the market. Same architecture and able to run same firmware as those sold today.
SolArk is a relatively expensive US branded model highly similar to less expensive Deye and others sold overseas. (but economical compared to retail price of an SMA or Schneider system, and all in one box.) It has different software, also US support, both of which users are quite happy with. It's hardware may have evolved a bit, customized at request of SolArk. There has been discussion about whether/how much SolArk was involved in its design, and the foreign models derived from it vs. the other way around. It supports parallel for more watts, or 3-phase. It is a high-frequency inverter, supports AC coupling with grid-tie PV inverters although reportedly that doesn't work as nicely as low-frequency inverters can do it.
Schneider is the evolution of Trace (who they acquired), a low-frequency design from several decades ago. Now supporting grid tie etc.
The designers of Trace designed earlier Outback inverters. Now are at Midnight, where they have introduced Midnight Rosie, a high-frequency inverter which looks very capable. Less than one year on the market but we expect it to be very good. Midnight was also working on a hot-swappable bank of inverters and charge controllers.
I don't have experience with any except SMA, but all of the above reportedly work well. Support of time-shifting for grid-tied use, and support of AC coupling, would vary.
Reliability from hardware to software is key. I want to set it up and only glance at it occasionally to update or general maintenance. I currently have a small 12v system with magnasine inverter and victron everything else. It has been extremely reliable. The magnasine has had its issues but for the most part reliable. Victron had a bad charge controller but customer service was great and no issues since.
I operated up to five SMA SWR2500U over 17 years, had two failures, calculate 32 years MTBF.
I now operate a number of Sunny Island and newer model Sunny Boy, 3 years and no failures.
Used to have 5 year warranty, then 20 year for Sunny Boy and 10 year on Sunny Island optional to 20 year. Sunny Boy Smart Energy warranted for 25 years (that would be the new Sunny Boy PV inverter. It has optional battery, but not to build a system larger than about 10kW.)
People report using Trace for something like 30 or 40 years.
