JHB73

The Deye/ Sunsynk 3 phase inverter has an advantage when your loads are not balanced. With 3 single phase 5kW inverters, your cap is 5kW per phase, even if there is no load on another phase. With the 12kW 3 phase, your cap is the total amount of power the inverter can provide, so if one phase has no load, that power is available for the remaining 2 phases.

Will these run on the Beaglebone black? It has eMMC storage built in - so shouldn't suffer from the SD card failure like the raspberry pi's

It may be possible to have a very low wattage LED bulb attached, but I won't risk my inverter, as I am not sure how many watts it was designed to supply. Relay coils are very low power.

Yes, it is supposed to give 220V out when the power is off, and then you just connect that to a relay with a 220V coil. I used a relay with to poles, one for netural-earth bonding, and the other for my Sonoff R2 mini, which has a switch input. You will just need to find a Tuya equivalent.

I think it is labeled ATS, but cannot find it now. There is also a tick-box on the UI to enable it called "Signal Island Mode" Good luck

The sunsynk has a connection strip for signals close to where the battery communication cable connects to the inverter. 2 of them send out 220V when the mains fail. The purpose of this is to connect a relay that will ground the load neutral so that an earth leakage would still work. I have a double pole relay on it, so use the other pole as a sensor.

I use a Sonoff Mini R2 as a sensor. Mine is connected to the inverter island port, but it would also work on raw mains. I have Sonoff switches on most other light switches, so I change the state of 2 lights when the Mini R2 changes states to indicate mains failure. The internet connection just has to be reliable.

The Sunsynk has a better user interface on the inverter. Non essential loads that are connected between the grid and the inverter, are shown separately. The Deye just adds everything together as "load" and you have no idea if that load is going through the inverter. It goes as far as beeping that you are exceeding the rating, when the load is before the inverter, but it doesn't show up as an alarm or anything, so I just turned the buzzer off. I won't say the Sunsynk interface is more westernized, the flow diagram is just more accurate. The cellphone app and web interface on the DEYE is better in my opinion than that of the Sunsynk. It gives you more control to customise what you see in the graphs and to hover over the legend to see only that graph dimming the rest. With the Sunsynk it is basically what you see is what you get. The Sunsynk allows you to change settings from remote, which is really important if you are going to use it. This alone may justify the price difference. Update: I requested remote access on my Deye, got approved, and now both are similar in that respect. Main difference then is local support for Sunsynk vs going through supplier for Deye.