Wiring Diagram MCP

An MCP (Model Context Protocol) server for designing complete electrical systems for campers, boats, and off-grid setups. Generates wiring diagrams and provides a full suite of electrical calculators.

Powered by VoltPlan.

Features

• Wiring diagrams — generate complete schematics as SVG or PNG
• Power budget — calculate daily energy consumption from a list of loads
• Battery bank sizing — determine capacity, number of batteries, and configuration
• Solar panel sizing — find the right solar wattage for your consumption and location
• Charging time — estimate charge duration from solar, shore, or alternator
• Inverter sizing — size an inverter for your AC loads with surge handling
• Battery configuration — series/parallel arrangement with wiring instructions
• Cable cross-section & resistance — find the right wire gauge with fuse recommendation
• Auto-generated protection components (shunt, main switch, low-voltage cutoff)
• Support for solar, shore power, wind, generator, and alternator charging systems
• Available as hosted remote MCP, local stdio, or self-hosted HTTP server

Quick Start — Claude Desktop

If you just want to use this with Claude Desktop, follow these steps:

1. Open Claude Desktop
2. Go to Settings (click your name in the bottom-left corner)
3. Click Developer, then Edit Config
4. This opens a file called claude_desktop_config.json. Paste the following into it:

{
  "mcpServers": {
    "wiring-diagram": {
      "url": "https://mcp.voltplan.app/mcp"
    }
  }
}

5. Save the file and restart Claude Desktop
6. You should now see a hammer icon in the chat input area — that means the tools are available

That's it! You can now ask Claude things like:

• "Draw me a wiring diagram for a camper van with a 100Ah LiFePO4 battery, LED lights, a fridge, and a solar charger."
• "I have LED lights (20W, 5h/day), a fridge (60W, 24/7), and two USB chargers (10W, 3h/day). What's my daily power consumption at 12V?"
• "Size a battery bank for 1600 Wh/day with 2 days of autonomy using 100Ah LiFePO4 batteries."
• "How many watts of solar panels do I need for 1600 Wh/day in Northern Europe?"
• "How long will it take to charge my 200Ah battery from 20% to full with a 600W solar setup?"
• "What cable size do I need for a 12V fridge that draws 5 amps, with 3 meters of cable?"
• "I want to run a microwave (800W) and a coffee machine (1000W) — what inverter do I need?"

Other Setup Options

Claude Code

claude mcp add wiring-diagram --transport http https://mcp.voltplan.app/mcp

Local via npx

Run locally without installation:

Claude Code:

claude mcp add wiring-diagram -- npx wiring-diagram-mcp

Claude Desktop (claude_desktop_config.json):

{
  "mcpServers": {
    "wiring-diagram": {
      "command": "npx",
      "args": ["wiring-diagram-mcp"]
    }
  }
}

Self-hosted HTTP server

npm install
npm run build
npm run start:http

The MCP server starts on http://localhost:3001/mcp.

Configuration

| Environment Variable | Default | Description | |---|---|---| | VOLTPLAN_API_URL | https://voltplan.app | URL of the VoltPlan instance | | PORT | 3001 | Port for the HTTP server |

MCP Tools

generate_wiring_diagram

Generate a complete electrical wiring diagram.

Parameters:

| Parameter | Type | Required | Description | |---|---|---|---| | systemName | string | yes | Name of the electrical system | | batteries | array | no | Battery specifications | | loads | array | no | Electrical loads / consumers | | chargers | array | no | Chargers with power source types | | format | "svg" or "png" | no | Output format (default: "svg") |

Example:

{
  "systemName": "Camper Van",
  "batteries": [
    { "name": "LiFePO4", "voltage": 12, "capacityAh": 100, "energyWh": 1280 }
  ],
  "loads": [
    { "name": "LED Lights", "power": 20, "voltage": 12, "current": 1.7 },
    { "name": "Fridge", "power": 60, "voltage": 12, "current": 5 }
  ],
  "chargers": [
    { "name": "Solar Charger", "inputVoltage": 48, "outputVoltage": 12, "power": 200, "sourceType": "solar" }
  ]
}

calculate_wire_gauge

Calculate the recommended cable cross-section for a DC circuit. Considers both ampacity (current carrying capacity) and voltage drop to find the optimal wire size. Also provides total resistance, power loss, and a fuse recommendation.

Parameters:

| Parameter | Type | Required | Description | |---|---|---|---| | voltage | number | yes | System voltage in volts (e.g. 12, 24, 48) | | current | number | no | Load current in amps (provide current or power) | | power | number | no | Load power in watts (provide current or power) | | cableLengthM | number | yes | One-way cable length in meters | | maxVoltageDropPercent | number | no | Max acceptable voltage drop in % (default: 3) | | temperatureCelsius | number | no | Ambient temperature in °C (default: 20) | | isRoundTrip | boolean | no | Account for both conductors (default: true) |

Example:

{
  "voltage": 12,
  "current": 10,
  "cableLengthM": 5,
  "maxVoltageDropPercent": 3
}

calculate_power_budget

Calculate total daily energy consumption from a list of loads. This is typically the first step in designing an off-grid system.

Parameters:

| Parameter | Type | Required | Description | |---|---|---|---| | systemVoltage | number | yes | System voltage (e.g. 12, 24, 48) | | loads | array | yes | List of loads, each with name, powerWatts, hoursPerDay, quantity |

Example:

{
  "systemVoltage": 12,
  "loads": [
    { "name": "LED Lights", "powerWatts": 20, "hoursPerDay": 5, "quantity": 1 },
    { "name": "Fridge", "powerWatts": 60, "hoursPerDay": 24, "quantity": 1 }
  ]
}

calculate_battery_bank

Size a battery bank based on daily consumption, autonomy days, and depth of discharge.

Parameters:

| Parameter | Type | Required | Description | |---|---|---|---| | dailyConsumptionWh | number | yes | Daily energy use in Wh | | daysOfAutonomy | number | no | Days without charging (default: 2) | | depthOfDischargePercent | number | no | Usable %. LiFePO4: 80, AGM: 50 (default: 80) | | systemVoltage | number | yes | Target system voltage | | singleBatteryAh | number | yes | Capacity of one battery | | singleBatteryVoltage | number | yes | Voltage of one battery |

calculate_solar_size

Calculate required solar panel wattage to cover daily consumption.

Parameters:

| Parameter | Type | Required | Description | |---|---|---|---| | dailyConsumptionWh | number | yes | Daily energy use in Wh | | peakSunHours | number | yes | Average daily peak sun hours for the location | | systemEfficiency | number | no | Efficiency factor (default: 0.85) |

calculate_charging_time

Estimate charging duration from any source, accounting for bulk and absorption phases.

Parameters:

| Parameter | Type | Required | Description | |---|---|---|---| | batteryCapacityAh | number | yes | Total bank capacity in Ah | | batteryVoltage | number | yes | Battery voltage | | currentStateOfChargePercent | number | yes | Current SoC (e.g. 20) | | targetStateOfChargePercent | number | no | Target SoC (default: 100) | | chargePowerWatts | number | yes | Charger output power in watts | | chargeCurrentAmps | number | no | Max charge current if limited by BMS |

calculate_inverter_size

Size an inverter for AC loads with surge handling and 25% headroom.

Parameters:

| Parameter | Type | Required | Description | |---|---|---|---| | systemVoltage | number | yes | DC system voltage | | loads | array | yes | AC loads, each with name, continuousWatts, optional surgeWatts, quantity |

calculate_battery_config

Determine series/parallel battery arrangement with step-by-step wiring instructions.

Parameters:

| Parameter | Type | Required | Description | |---|---|---|---| | targetVoltage | number | yes | Desired system voltage | | targetCapacityAh | number | yes | Desired total capacity in Ah | | singleBatteryVoltage | number | yes | Voltage of one battery | | singleBatteryAh | number | yes | Capacity of one battery in Ah |

list_component_types

Returns all available component types with example configurations. Useful for understanding valid parameters before generating a diagram.

Docker

docker build -t wiring-diagram-mcp .
docker run -p 3001:3001 wiring-diagram-mcp

License

MIT