I ran the Solis TechView apk in an Android emulator and monitored the network traffic with Wireshark.
Basically reads/writes registers in a similar way to modbus. I don’t really know modbus but the registers appear to be the same as in this document.
The code and discussion can be found here. It’s the zip file to download. Not the best use of github but it works.
I have not tested or tried setting at registers. This may or may not work.
The APK will ONLY WORK is directly connect to the WiFi access point. The default password for the direct connect is admin, admin.
On the web interface setup up the Network Setting->Network Connection 2 Setting to:
Protocol: TCP Server
Local Port: 8000 ← this is what is used by the integration.
Passwords for APK:
advanced user: solis123456
installer: solis123