{
  "node": {
    "id": "term:negative-delta-v",
    "type": "Term",
    "label": "Negative delta V",
    "properties": {
      "id": "negative-delta-v",
      "name": "Negative delta V",
      "abbr": "−ΔV",
      "aka": [
        "-dV",
        "-dV/dt",
        "NDV",
        "minus delta V",
        "zero delta V",
        "peak voltage detection"
      ],
      "section": "topic-charging",
      "definition": "The small fall in a nickel cell’s voltage just after full charge, as overcharge heats it, used to end a fast charge. NiCd shows about 10–30 mV per cell, NiMH only around 5–10 mV and barely any below 0.5C, so NiMH chargers often stop at the voltage peak or plateau instead and back it up with dT/dt.",
      "related": [
        "charge-termination",
        "dt-dt-termination",
        "nickel-cadmium",
        "nickel-metal-hydride",
        "fast-charging"
      ],
      "url": "https://lemonergy.com/learn/glossary/negative-delta-v/",
      "mentions": [
        "overcharge"
      ]
    }
  },
  "edges": [
    {
      "id": "edge:belongsTo/term:negative-delta-v/topic:topic-charging",
      "source": "term:negative-delta-v",
      "target": "topic:topic-charging",
      "type": "belongsTo",
      "properties": {
        "sourceFile": "terms.json"
      }
    },
    {
      "id": "edge:relatedTo/term:negative-delta-v/term:charge-termination",
      "source": "term:negative-delta-v",
      "target": "term:charge-termination",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:relatedTo/term:negative-delta-v/term:dt-dt-termination",
      "source": "term:negative-delta-v",
      "target": "term:dt-dt-termination",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:relatedTo/term:negative-delta-v/term:nickel-cadmium",
      "source": "term:negative-delta-v",
      "target": "term:nickel-cadmium",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:relatedTo/term:negative-delta-v/term:nickel-metal-hydride",
      "source": "term:negative-delta-v",
      "target": "term:nickel-metal-hydride",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:relatedTo/term:negative-delta-v/term:fast-charging",
      "source": "term:negative-delta-v",
      "target": "term:fast-charging",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:mentions/negative-delta-v/overcharge",
      "source": "term:negative-delta-v",
      "target": "term:overcharge",
      "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-charging",
      "type": "Topic",
      "label": "Charging and discharging",
      "properties": {
        "id": "topic-charging",
        "name": "Charging and discharging",
        "lede": "How current goes in and comes out, and the limits that stop it.",
        "context": "Separate regulation from availability.",
        "example": "The same CC–CV law can operate overnight or during a short depot stop.",
        "lesson_url": "https://lemonergy.com/learn/fundamentals/capacity-and-c-rate/",
        "lesson_label": "Open charging quantities"
      }
    },
    {
      "id": "term:charge-termination",
      "type": "Term",
      "label": "Charge termination",
      "properties": {
        "id": "charge-termination",
        "name": "Charge termination",
        "aka": [
          "end-of-charge detection",
          "full-charge detection"
        ],
        "section": "topic-charging",
        "definition": "How a charger decides that a battery is full. Lithium-ion chargers end the constant-voltage stage when current falls to the taper current; nickel chargers watch for a small voltage drop or a fast temperature rise; lead–acid chargers drop to a float voltage. A safety timer and a temperature limit back up every method.",
        "related": [
          "taper-current",
          "negative-delta-v",
          "dt-dt-termination",
          "cc-cv-charging",
          "trickle-charge"
        ],
        "url": "https://lemonergy.com/learn/glossary/charge-termination/",
        "mentions": [
          "charger"
        ]
      }
    },
    {
      "id": "term:dt-dt-termination",
      "type": "Term",
      "label": "dT/dt termination",
      "properties": {
        "id": "dt-dt-termination",
        "name": "dT/dt termination",
        "aka": [
          "ΔT/Δt termination",
          "temperature-rise termination",
          "rate-of-temperature-rise termination"
        ],
        "section": "topic-charging",
        "definition": "Ending a nickel-cell fast charge when the temperature climbs faster than a set rate, typically about 1 °C per minute, because once the cell is full the charge no longer stored chemically turns into heat. It needs a thermistor against the cells and a charge rate of roughly 0.5C or more to produce a clear rise.",
        "related": [
          "charge-termination",
          "negative-delta-v",
          "temperature-sensor",
          "nickel-metal-hydride",
          "oxygen-recombination"
        ],
        "url": "https://lemonergy.com/learn/glossary/dt-dt-termination/",
        "mentions": []
      }
    },
    {
      "id": "term:nickel-cadmium",
      "type": "Term",
      "label": "Nickel–cadmium battery",
      "properties": {
        "id": "nickel-cadmium",
        "name": "Nickel–cadmium battery",
        "abbr": "NiCd",
        "aka": [
          "NiCad",
          "Ni–Cd"
        ],
        "section": "topic-other-chemistries",
        "definition": "A 1.2 V aqueous cell, rugged and able to deliver very high currents, but containing toxic cadmium and prone to the memory effect. It is now restricted in most consumer uses and survives in aviation and emergency lighting.",
        "related": [
          "memory-effect",
          "nickel-metal-hydride",
          "recycling",
          "reconditioning",
          "iec-61951"
        ],
        "url": "https://lemonergy.com/learn/glossary/nickel-cadmium/",
        "mentions": []
      }
    },
    {
      "id": "term:nickel-metal-hydride",
      "type": "Term",
      "label": "Nickel–metal hydride battery",
      "properties": {
        "id": "nickel-metal-hydride",
        "name": "Nickel–metal hydride battery",
        "abbr": "NiMH",
        "section": "topic-other-chemistries",
        "definition": "A 1.2 V aqueous cell with a nickel hydroxide positive electrode and a hydrogen-absorbing alloy negative. It powered hybrid cars for two decades and is tolerant of abuse, but lithium-ion stores two to three times more energy per kilogram.",
        "related": [
          "hybrid-vehicle",
          "memory-effect",
          "specific-energy",
          "bipolar-battery",
          "nickel-hydrogen",
          "lsd-nimh"
        ],
        "url": "https://lemonergy.com/learn/glossary/nickel-metal-hydride/",
        "mentions": [
          "electrode",
          "positive-electrode"
        ]
      }
    },
    {
      "id": "term:fast-charging",
      "type": "Term",
      "label": "Fast charging",
      "properties": {
        "id": "fast-charging",
        "name": "Fast charging",
        "section": "topic-charging",
        "definition": "Charging intended to replenish a specified amount of energy or state of charge in a short time. There is no universal C-rate threshold: performance depends on cell chemistry, temperature, starting state and power limits. High current can increase heating and lithium-plating risk, requiring appropriate limits.",
        "related": [
          "lithium-plating",
          "c-rate",
          "cc-cv-charging",
          "dc-fast-charging",
          "thermal-management",
          "mscc"
        ],
        "url": "https://lemonergy.com/learn/glossary/fast-charging/",
        "mentions": [
          "state-of-charge"
        ]
      }
    },
    {
      "id": "term:overcharge",
      "type": "Term",
      "label": "Overcharge",
      "properties": {
        "id": "overcharge",
        "name": "Overcharge",
        "section": "topic-charging",
        "definition": "Charging past the upper cutoff voltage. The positive electrode over-delithiates and releases oxygen, the electrolyte oxidises and lithium plates on the negative, so an unprotected overcharge can end in thermal runaway.",
        "related": [
          "cutoff-voltage",
          "thermal-runaway",
          "bms",
          "overcharge-test",
          "electrolyte-decomposition"
        ],
        "url": "https://lemonergy.com/learn/glossary/overcharge/",
        "mentions": [
          "electrode",
          "positive-electrode",
          "electrolyte"
        ]
      }
    }
  ]
}