Point of all that?
* If you wanted to hack the GroWatt protocol, all you would have to do is sniff the UART
The interface between the WiFi dongle and the Inverter is USB. If you inspect closely you will see it converts to UART. If you simply attach GND and TX to the GND and RX of an Arduino and pick the correct baud, you can start spilling ONE SIDE of that communication to the terminal, where you can later parse it.
If you use a second arduino, or a second uart port, you can then grab the other side of the communication. OBVIOUSLY it is easier if you synchronize them (L O L) and I suggest doing it on a heartbeat. I.E. if you just log the ASYNC data you will have no way to line it up. If you instead log against a heartbeat you can line the two data streams up.
You then initiate
* Like sending a command
You then watch the 5 or 15 back and forths
Now you have a backdoor into the GroWatt - and - this may be at the AT command level or .... right? Because it is a standard WiFi nugget they have on there. The USB is THAT interface, the one between the actual WiFi node and the uProcessor, so that means
* That the language being spoken will comply with the datasheet of the WiFi "chip"
* I.E. that is what all the garble is wrapped around the snips of data you want
-methods