{
  "$schema": "https://raw.githubusercontent.com/nobrega8/mbmap-library/main/schema/mbmap-2.schema.json",
  "mbmap": 2,
  "vendor": "BYD",
  "model": "Battery-Box Premium",
  "models": [
    "Battery-Box Premium HVS",
    "Battery-Box Premium HVM",
    "Battery-Box Premium HVL",
    "Battery-Box Premium LVS",
    "Battery-Box Premium LVL"
  ],
  "vendor_website": "byd.com",
  "description": "Battery-Box Premium battery management unit, read-only status over its Ethernet port",
  "revision": 1,
  "revised": "2026-10-18",
  "source": "Community reverse engineering of the BE Connect Plus protocol (sarnau/BYD-Battery-Box-Infos); BYD publishes no register map",
  "sources": [
    {
      "title": "sarnau/BYD-Battery-Box-Infos, Read_Modbus.py and README",
      "url": "https://github.com/sarnau/BYD-Battery-Box-Infos",
      "note": "Unofficial; register meanings come from the reference script, not from a BYD document"
    }
  ],
  "notes": [
    "Unofficial: BYD does not publish this protocol and the registers were worked out from the installer software. Treat every value as unchecked and keep to reading.",
    "The battery management unit answers on its fixed Ethernet address 192.168.16.254, port 8080, unit id 1. It speaks Modbus RTU framing (with CRC) carried over a TCP connection, not Modbus TCP with the MBAP header; a client must be set to RTU-over-TCP.",
    "Only one client can be connected at a time: the BE Connect Plus app and a monitoring script cannot run together. Wi-Fi access of the unit is switched off after a while, so the wired Ethernet port is the practical route; the unit needs a route to 192.168.16.0/24.",
    "Readable blocks found by the community: 0x0000 to 0x0066 (hardware information and configuration), 0x0500 to 0x0518 (current status), 0x0550 to 0x0557 (BMS information) and 0x05A0 to 0x05A7 (history). The last two are request-and-response areas and are not mapped; registers 0x0010 to 0x0012 hold the hardware configuration and must never be written.",
    "The bit meanings of the error bitmask at 0x050D are not mapped; the reference script prints it as a hexadecimal number."
  ],
  "protocol": "tcp",
  "unit_id": 1,
  "port": 8080,
  "byte_order": "big",
  "word_order": "big",
  "address_base": 0,
  "x_status": "unofficial",
  "enums": {
    "area": {"1": "A", "2": "B"},
    "application": {"0": "Off Grid", "1": "On Grid", "2": "Backup"},
    "phase": {"0": "Single", "1": "Three"}
  },
  "registers": [
    {"name": "Serial number", "group": "Device", "area": "holding", "address": 0, "type": "string", "access": "R", "length": 9, "role": "serial", "description": "18 ASCII characters; the prefix tells the type: P03 or E0P3 for high-voltage packs (HVL, HVM, HVS), P02 or P011 for low-voltage ones (LVL, LVFlex, LVS)"},
    {"name": "BMU A version major", "group": "Device", "area": "holding", "address": 12, "type": "uint16", "access": "R", "bit": 8, "bits": 8, "description": "Firmware area A of the battery management unit, shown as V<major>.<minor>"},
    {"name": "BMU A version minor", "group": "Device", "area": "holding", "address": 12, "type": "uint16", "access": "R", "bit": 0, "bits": 8},
    {"name": "BMU B version major", "group": "Device", "area": "holding", "address": 13, "type": "uint16", "access": "R", "bit": 8, "bits": 8, "description": "Firmware area B of the battery management unit"},
    {"name": "BMU B version minor", "group": "Device", "area": "holding", "address": 13, "type": "uint16", "access": "R", "bit": 0, "bits": 8},
    {"name": "BMS version major", "group": "Device", "area": "holding", "address": 14, "type": "uint16", "access": "R", "bit": 8, "bits": 8, "description": "Battery management system firmware"},
    {"name": "BMS version minor", "group": "Device", "area": "holding", "address": 14, "type": "uint16", "access": "R", "bit": 0, "bits": 8},
    {"name": "BMU working area", "group": "Device", "area": "holding", "address": 15, "type": "uint16", "access": "R", "bit": 8, "bits": 8, "enum": "area"},
    {"name": "BMS working area", "group": "Device", "area": "holding", "address": 15, "type": "uint16", "access": "R", "bit": 0, "bits": 8, "enum": "area"},
    {"name": "Module quantity", "group": "Device", "area": "holding", "address": 16, "type": "uint16", "access": "R", "bit": 0, "bits": 4},
    {"name": "BMS quantity", "group": "Device", "area": "holding", "address": 16, "type": "uint16", "access": "R", "bit": 4, "bits": 4},
    {"name": "Inverter code", "group": "Device", "area": "holding", "address": 16, "type": "uint16", "access": "R", "bit": 8, "bits": 4, "description": "Index into the list of inverters the pack was configured for; the list in the reference script has more entries than four bits can address. Do not change it: it is the hardware configuration"},
    {"name": "Application", "group": "Device", "area": "holding", "address": 17, "type": "uint16", "access": "R", "bit": 8, "bits": 8, "enum": "application"},
    {"name": "Battery type code", "group": "Device", "area": "holding", "address": 17, "type": "uint16", "access": "R", "bit": 0, "bits": 8, "description": "Index into the battery type list of the serial prefix: HVL, HVM, HVS for P03 and E0P3, or LVL, LVFlex (Lite), LVS / LVS Lite for P02 and P011"},
    {"name": "Phase", "group": "Device", "area": "holding", "address": 18, "type": "uint16", "access": "R", "bit": 8, "bits": 8, "enum": "phase"},
    {"name": "State of charge", "group": "Battery", "area": "holding", "address": 1280, "type": "uint16", "access": "R", "unit": "%"},
    {"name": "Maximum cell voltage", "group": "Battery", "area": "holding", "address": 1281, "type": "uint16", "access": "R", "scale": 0.01, "unit": "V"},
    {"name": "Minimum cell voltage", "group": "Battery", "area": "holding", "address": 1282, "type": "uint16", "access": "R", "scale": 0.01, "unit": "V"},
    {"name": "State of health", "group": "Battery", "area": "holding", "address": 1283, "type": "uint16", "access": "R", "unit": "%"},
    {"name": "Current", "group": "Battery", "area": "holding", "address": 1284, "type": "int16", "access": "R", "scale": 0.1, "unit": "A"},
    {"name": "Battery voltage", "group": "Battery", "area": "holding", "address": 1285, "type": "uint16", "access": "R", "scale": 0.01, "unit": "V"},
    {"name": "Maximum cell temperature", "group": "Battery", "area": "holding", "address": 1286, "type": "uint16", "access": "R", "unit": "°C"},
    {"name": "Minimum cell temperature", "group": "Battery", "area": "holding", "address": 1287, "type": "uint16", "access": "R", "unit": "°C"},
    {"name": "BMU temperature", "group": "Battery", "area": "holding", "address": 1288, "type": "uint16", "access": "R", "unit": "°C"},
    {"name": "BMU version major", "group": "Battery", "area": "holding", "address": 1290, "type": "uint16", "access": "R", "bit": 8, "bits": 8},
    {"name": "BMU version minor", "group": "Battery", "area": "holding", "address": 1290, "type": "uint16", "access": "R", "bit": 0, "bits": 8},
    {"name": "Error bitmask", "group": "Battery", "area": "holding", "address": 1293, "type": "uint16", "access": "R", "description": "Bit set for each error; the bit meanings of the pack are not documented here"},
    {"name": "P/T version major", "group": "Battery", "area": "holding", "address": 1294, "type": "uint16", "access": "R", "bit": 8, "bits": 8, "description": "Parameter table version"},
    {"name": "P/T version minor", "group": "Battery", "area": "holding", "address": 1294, "type": "uint16", "access": "R", "bit": 0, "bits": 8},
    {"name": "Output voltage", "group": "Battery", "area": "holding", "address": 1296, "type": "uint16", "access": "R", "scale": 0.01, "unit": "V"},
    {"name": "Charge cycles", "group": "Battery", "area": "holding", "address": 1297, "type": "uint16", "access": "R", "description": "Read as one register by the reference script; the neighbouring register may hold the high word"},
    {"name": "Discharge cycles", "group": "Battery", "area": "holding", "address": 1299, "type": "uint16", "access": "R", "description": "Read as one register by the reference script"}
  ]
}