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