Reverse engineering a 11kWh BYD HVM battery system, connected to a Fronius Gen24 Symo 5.0 Hybrid inverter
Open .odg with e.g LibreOffice Draw
Open with HHD Device Monitoring Studio https://www.hhdsoftware.com/device-monitoring-studio
Open .ods file with your favourite spreadsheet tool (e.g. LibreOffice Calc) The Battery has registers that the Fronius Inverter requests to read. There is also a write event that periodically appears (see logs) During startup more bus activity is present compared to sitting idle.
Registers used: 101:["SI", 1], 103:["BY", "D ", 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0], 119:["BY", "D ", "Ba", "tt", "er", "y-", "Bo", "x ", "Pr", "em", "iu", "m ", "HV", 0, 0, 0], 135:["5.", "0", 0, 0, 0, 0, 0, 0, "3.", "16", 0, 0, 0, 0, 0, 0], 151:["P0", "30", "T0", "20", "Z2", "00", "81", "03", "48", "80", " ", " ", 0, 0, 0, 0], 167:[1, 0], 201:[0, 0, 11059, 10240, 10240, 2336, 1600, 13312, 10, 13312, 10, 0, 0], 301:[1, 0, 128, 470, 10948, 514, 0, 8352, 0, 0, 2058, 0, 60, 70, 0, 0, 16, 22741, 0, 0, 13, 52064, 80, 9900], 401:[0]*20, 1001:[0]*100, 12289:[0]*768})
By setting up modbus registers like above, a battery will appear with 5% SOC in the Fronius inverters app.
Internal pictures from when BYD box was opened
Windows program for connecting to BYD battery and doing firmware update and diagnostics over WIFI
Usefull manuals from BYD webpage.