{
  "slug": "battery-runtime",
  "title": "Battery Runtime Calculator",
  "heading": "Battery Life & Runtime Calculator",
  "category": "math",
  "url": "https://www.revenuelab.fyi/toolbox/battery-runtime",
  "summary": "How long a battery lasts under a given load.",
  "description": "Capacity in amp-hours divided by draw in amps gives raw hours; a depth-of-discharge limit keeps the estimate honest for lead-acid and lithium packs.",
  "formula": "Hours = Ah × DoD ÷ load A",
  "dateModified": "2026-09-30",
  "run_url": "https://www.revenuelab.fyi/api/public/calc?tool=battery-runtime",
  "inputs": [
    {
      "id": "ah",
      "label": "Battery capacity",
      "kind": "number",
      "hint": null,
      "default": 100,
      "unit": "Ah",
      "min": 0.1,
      "max": null
    },
    {
      "id": "volts",
      "label": "Battery voltage",
      "kind": "number",
      "hint": null,
      "default": 12,
      "unit": "V",
      "min": 1,
      "max": null
    },
    {
      "id": "watts",
      "label": "Load",
      "kind": "number",
      "hint": null,
      "default": 120,
      "unit": "W",
      "min": 0.1,
      "max": null
    },
    {
      "id": "dod",
      "label": "Usable depth of discharge",
      "kind": "number",
      "hint": null,
      "default": 80,
      "unit": "%",
      "min": 10,
      "max": 100
    }
  ],
  "outputs": [
    {
      "id": "hours",
      "label": "Runtime (hours)",
      "format": "decimal",
      "hint": null,
      "primary": true
    },
    {
      "id": "minutes",
      "label": "Runtime (minutes)",
      "format": "decimal",
      "hint": null,
      "primary": false
    },
    {
      "id": "amps",
      "label": "Load current (A)",
      "format": "decimal",
      "hint": null,
      "primary": false
    },
    {
      "id": "wh",
      "label": "Usable energy (Wh)",
      "format": "decimal",
      "hint": null,
      "primary": false
    }
  ],
  "worked_example": {
    "inputs": [
      "Battery capacity: 100 Ah",
      "Battery voltage: 12 V",
      "Load: 120 W",
      "Usable depth of discharge: 80 %"
    ],
    "outputs": [
      "Runtime (hours): 8",
      "Runtime (minutes): 480",
      "Load current (A): 10",
      "Usable energy (Wh): 960"
    ]
  },
  "how_to": {
    "title": "How to use this",
    "steps": [
      "Enter battery capacity (Ah).",
      "Enter battery voltage (V).",
      "Enter load (W).",
      "Enter usable depth of discharge (%).",
      "Read your runtime (hours) on the right — it updates as you type.",
      "Hit Share to keep the scenario or send it to someone."
    ]
  },
  "scenarios": [
    {
      "name": "Conservative",
      "description": "Lower-end numbers — what if things land soft?",
      "values": {
        "ah": 60,
        "volts": 7,
        "watts": 72,
        "dod": 50
      }
    },
    {
      "name": "Typical",
      "description": "Defaults — the most common real-world setup.",
      "values": {
        "ah": 100,
        "volts": 12,
        "watts": 120,
        "dod": 80
      }
    },
    {
      "name": "Ambitious",
      "description": "Higher-end numbers — what if things really pop?",
      "values": {
        "ah": 160,
        "volts": 19,
        "watts": 192,
        "dod": 100
      }
    }
  ],
  "limitations": [
    "Results are rounded for display; the underlying calculation keeps full precision.",
    "Very large or very small inputs may hit floating-point limits in the browser.",
    "Inputs outside the accepted range are clamped rather than rejected."
  ],
  "faq": [
    {
      "q": "How does the battery life & runtime calculator work?",
      "a": "Capacity in amp-hours divided by draw in amps gives raw hours; a depth-of-discharge limit keeps the estimate honest for lead-acid and lithium packs. The underlying maths is: Hours = Ah × DoD ÷ load A"
    },
    {
      "q": "What do I need to enter?",
      "a": "4 values: battery capacity, battery voltage, load, and usable depth of discharge. Each field starts with a sensible default, so you can change one number at a time and watch the result move."
    },
    {
      "q": "What does the runtime (hours) result mean?",
      "a": "It is returned as a decimal number and updates live as you edit the inputs, so you can compare two or three versions of a scenario in a few seconds."
    },
    {
      "q": "Is this calculator free, and do I need an account?",
      "a": "Yes, it's free, and no account is required. Nothing you type is stored on our servers — the maths runs entirely in your browser."
    },
    {
      "q": "How accurate is the result?",
      "a": "It applies the standard formula exactly, so the arithmetic is precise. Results are rounded for display; the underlying calculation keeps full precision."
    },
    {
      "q": "Who is this tool for?",
      "a": "It's built for students, developers, and anyone who needs the answer right now without setting up a spreadsheet."
    }
  ],
  "related": [],
  "license": "CC-BY-4.0",
  "citation": "RevenueLab — Battery Runtime Calculator (https://www.revenuelab.fyi/toolbox/battery-runtime)"
}