{
  "node": {
    "id": "term:j1939",
    "type": "Term",
    "label": "SAE J1939",
    "properties": {
      "id": "j1939",
      "name": "SAE J1939",
      "section": "topic-data",
      "definition": "The CAN-based protocol of trucks, buses and off-highway machines, with 29-bit identifiers and standard parameter groups. Commercial-vehicle batteries and chargers often report SOC, limits and faults as J1939 messages, and the bus FMS interface builds on it.",
      "related": [
        "can-bus",
        "fms-interface",
        "dbc",
        "electric-bus",
        "canopen"
      ],
      "url": "https://lemonergy.com/learn/glossary/j1939/",
      "mentions": [
        "state-of-charge"
      ]
    }
  },
  "edges": [
    {
      "id": "edge:4146",
      "source": "term:j1939",
      "target": "topic:topic-data",
      "type": "belongsTo",
      "properties": {
        "sourceFile": "terms.json"
      }
    },
    {
      "id": "edge:4147",
      "source": "term:j1939",
      "target": "term:can-bus",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:4148",
      "source": "term:j1939",
      "target": "term:fms-interface",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:4149",
      "source": "term:j1939",
      "target": "term:dbc",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:4150",
      "source": "term:j1939",
      "target": "term:electric-bus",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:4151",
      "source": "term:j1939",
      "target": "term:canopen",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:mentions/j1939/state-of-charge",
      "source": "term:j1939",
      "target": "term:state-of-charge",
      "type": "mentions",
      "properties": {
        "sourceFile": "terms.json",
        "method": "build_glossary.mention_index + mentions",
        "field": "definition",
        "meaning": "Text mention; not a causal claim"
      }
    }
  ],
  "neighbors": [
    {
      "id": "topic:topic-data",
      "type": "Topic",
      "label": "Data, communication and electronics",
      "properties": {
        "id": "topic-data",
        "name": "Data, communication and electronics",
        "lede": "The control units, chips, protocols and file formats through which a battery is measured, controlled and logged.",
        "context": "Separate quantities from encoding and transport.",
        "example": "2500 in a log might mean 25.00 °C, 2.5 V or raw counts. Units and scale must accompany the value.",
        "lesson_url": "https://lemonergy.com/learn/fundamentals/battery-basics/",
        "lesson_label": "Open battery basics"
      }
    },
    {
      "id": "term:can-bus",
      "type": "Term",
      "label": "CAN bus",
      "properties": {
        "id": "can-bus",
        "name": "CAN bus",
        "aka": [
          "Controller Area Network",
          "ISO 11898"
        ],
        "section": "topic-pack",
        "definition": "The serial network over which a BMS talks to the vehicle or inverter: a two-wire differential bus, defined in ISO 11898, carrying short prioritised messages at up to 1 Mbit/s, or faster with CAN FD. Every node hears every message, and a dominant bit wins arbitration without any collision.",
        "related": [
          "can-high-low",
          "can-fd",
          "termination-resistor",
          "bms",
          "lin-bus",
          "fms-interface"
        ],
        "url": "https://lemonergy.com/learn/glossary/can-bus/",
        "mentions": [
          "inverter"
        ]
      }
    },
    {
      "id": "term:fms-interface",
      "type": "Term",
      "label": "FMS interface",
      "properties": {
        "id": "fms-interface",
        "name": "FMS interface",
        "aka": [
          "FMS standard",
          "bus FMS"
        ],
        "section": "topic-pack",
        "definition": "The manufacturer-independent CAN data interface of trucks and buses, defined by the major European OEMs, that exposes vehicle data — including, for electric vehicles, battery state of charge, charging status and energy consumption — to fleet-management telematics.",
        "related": [
          "can-bus",
          "vdv-301",
          "fleet-telematics",
          "state-of-charge",
          "electric-bus",
          "j1939"
        ],
        "url": "https://lemonergy.com/learn/glossary/fms-interface/",
        "mentions": [
          "differential-electrochemical-mass-spectrometry"
        ]
      }
    },
    {
      "id": "term:dbc",
      "type": "Term",
      "label": "DBC file",
      "properties": {
        "id": "dbc",
        "name": "DBC file",
        "abbr": ".dbc",
        "aka": [
          "CAN database"
        ],
        "section": "topic-data",
        "definition": "The de-facto text format, from Vector, that describes a CAN network: which messages exist, their identifiers and timing, and how each signal is packed, scaled and named. Without the BMS’s DBC a CAN log is just numbers.",
        "related": [
          "can-bus",
          "blf",
          "asc-log",
          "arxml",
          "j1939"
        ],
        "url": "https://lemonergy.com/learn/glossary/dbc/",
        "mentions": [
          "bms"
        ]
      }
    },
    {
      "id": "term:electric-bus",
      "type": "Term",
      "label": "Electric bus",
      "properties": {
        "id": "electric-bus",
        "name": "Electric bus",
        "abbr": "e-bus",
        "section": "topic-applications",
        "definition": "A battery-electric city or coach bus, with packs of 300–700 kWh on the roof and at the rear, LFP or NMC, charged overnight in the depot or at the terminus by pantograph. Its duty cycle — long hours, deep daily cycles, a twelve-year life — makes battery aging the central engineering question.",
        "related": [
          "depot-charging",
          "pantograph-charging",
          "vdv",
          "sort-cycle",
          "total-cost-of-ownership",
          "opportunity-charging"
        ],
        "url": "https://lemonergy.com/learn/glossary/electric-bus/",
        "mentions": [
          "kilowatt-hour"
        ]
      }
    },
    {
      "id": "term:canopen",
      "type": "Term",
      "label": "CANopen",
      "properties": {
        "id": "canopen",
        "name": "CANopen",
        "aka": [
          "CiA 418",
          "CiA 419"
        ],
        "section": "topic-data",
        "definition": "A higher-layer protocol on CAN used in industrial machines, forklifts and light vehicles; device profiles CiA 418 and 419 define how a battery module and a charger exchange status and limits.",
        "related": [
          "can-bus",
          "j1939",
          "modbus"
        ],
        "url": "https://lemonergy.com/learn/glossary/canopen/",
        "mentions": [
          "charger"
        ]
      }
    },
    {
      "id": "term:state-of-charge",
      "type": "Term",
      "label": "State of charge",
      "properties": {
        "id": "state-of-charge",
        "name": "State of charge",
        "abbr": "SOC",
        "section": "topic-state",
        "definition": "How full a cell is, as a fraction of its available capacity. State of charge, like temperature, affects how fast a stored cell ages.",
        "unit": "%",
        "related": [
          "depth-of-discharge",
          "ocv-soc-curve",
          "coulomb-counting",
          "state-of-health",
          "bms"
        ],
        "lesson": "fundamentals/battery-aging/#storage-soc",
        "example": {
          "title": "Interpret a charge inventory",
          "text": "If available capacity is 5 Ah and 3 Ah remains by the chosen estimator, SOC is 60%. A different estimate of available capacity changes this percentage, so compare SOC values only with the capacity convention recorded."
        },
        "url": "https://lemonergy.com/learn/glossary/state-of-charge/",
        "mentions": [
          "usable-capacity"
        ]
      }
    }
  ]
}