VoltPlan Wiring Diagrams

yuzu-hub/wiring-diagram-mcp

Gives Claude the math and tooling to size 12V/24V/48V electrical systems for boats, vans, and off-grid builds. Nine tools cover power budgets, battery bank sizing, wire gauge selection with voltage drop calculations, solar panel sizing, inverter specs, and full wiring diagram generation as SVG or PNG. The calculations run locally in the MCP server while diagrams render through the VoltPlan API. You'd reach for this when refitting a boat or converting a van and you're tired of redoing wire gauge math every time a load changes. Hosted at mcp.voltplan.app/mcp or run locally via npx. Built by the author while rewiring a 30-foot boat in the Netherlands.

tools: 9
transport: STDIO, HTTP
env var: 1
last updated: Oct 26, 2026

View on GitHub

Install

From registry metadata

$ npx add-mcp https://mcp.voltplan.app/mcp --name wiring-diagram-mcp

Run in your terminal. add-mcp asks which agents to add it to (Claude Code, Codex, Cursor and more). Add -g to install it for every project.

Review the command, arguments and environment values before installing. MCP servers run with your local permissions.

Other ways

Claude Code

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

Run in your terminal. Add --scope user to make it available in every project.

Tools

Verified live · 9 tools

Verified live against the running server on Nov 6, 2026.

generate_wiring_diagramGenerate an electrical wiring diagram for campers, boats, or off-grid setups. Returns the schematic as an image (batteries, chargers, protection components, loads) and a link that opens it in the VoltPlan editor to refine, save and turn into a shopping list. Protection compone...5 params

Generate an electrical wiring diagram for campers, boats, or off-grid setups. Returns the schematic as an image (batteries, chargers, protection components, loads) and a link that opens it in the VoltPlan editor to refine, save and turn into a shopping list. Protection compone...

Parameters* required

batteriesarray

Batteries in the system

chargersarray

Chargers with their power sources

formatstring

png (default): an image the client displays. svg: SVG markup as text, without component icons, for clients that save or post-process files.one of png · svgdefault: png

loadsarray

Electrical loads / consumers

systemName*string

Name of the electrical system (e.g. "My Camper Van")

list_component_typesList all available component types and example configurations for building wiring diagrams. Use this to understand what parameters are needed before calling generate_wiring_diagram.

List all available component types and example configurations for building wiring diagrams. Use this to understand what parameters are needed before calling generate_wiring_diagram.

No parameters. Call it with no arguments.

calculate_wire_gaugeCalculate the recommended wire gauge / cable cross-section for a DC circuit. Considers both ampacity (current carrying capacity) and voltage drop to recommend the optimal cable size. Also returns total resistance, power loss, and a fuse recommendation. Supports copper conducto...7 params

Calculate the recommended wire gauge / cable cross-section for a DC circuit. Considers both ampacity (current carrying capacity) and voltage drop to recommend the optimal cable size. Also returns total resistance, power loss, and a fuse recommendation. Supports copper conducto...

Parameters* required

cableLengthM*number

One-way cable length in meters

currentnumber

Load current in amps. Provide either current or power.

isRoundTripboolean

Account for both positive and negative conductor (default: true). Set to false for chassis-ground returns.default: true

maxVoltageDropPercentnumber

Maximum acceptable voltage drop in percent (default: 3%)default: 3

powernumber

Load power in watts. Will be converted to current using the voltage. Provide either current or power.

temperatureCelsiusnumber

Ambient temperature in °C (default: 20°C). Affects copper resistance.default: 20

voltage*number

System voltage in volts (e.g. 12, 24, 48)

calculate_power_budgetCalculate total daily energy consumption from a list of electrical loads. Each load specifies its power draw, how many hours per day it runs, and quantity. Returns total daily energy (Wh and Ah), peak power draw, and average power. This is typically the first step in sizing a...2 params

Calculate total daily energy consumption from a list of electrical loads. Each load specifies its power draw, how many hours per day it runs, and quantity. Returns total daily energy (Wh and Ah), peak power draw, and average power. This is typically the first step in sizing a...

Parameters* required

loads*array

List of electrical loads to include in the budget

systemVoltage*number

System voltage in volts (e.g. 12, 24, 48)

calculate_battery_bankCalculate the recommended battery bank size based on daily energy consumption. Accounts for days of autonomy (how many days without charging) and depth of discharge. Returns required capacity, number of batteries, and wiring configuration.6 params

Calculate the recommended battery bank size based on daily energy consumption. Accounts for days of autonomy (how many days without charging) and depth of discharge. Returns required capacity, number of batteries, and wiring configuration.

Parameters* required

dailyConsumptionWh*number

Daily energy consumption in watt-hours (from calculate_power_budget)

daysOfAutonomynumber

Days the system should run without any charging (default: 2)default: 2

depthOfDischargePercentnumber

Usable percentage of battery capacity. LiFePO4: 80-90%, AGM: 50%, Gel: 50% (default: 80)default: 80

singleBatteryAh*number

Capacity of a single battery in amp-hours (e.g. 100, 200)

singleBatteryVoltage*number

Voltage of a single battery (e.g. 12.8 for LiFePO4, 12 for lead-acid)

systemVoltage*number

Target system voltage in volts (e.g. 12, 24, 48)

calculate_solar_sizeCalculate the required solar panel wattage to cover daily energy consumption. Accounts for peak sun hours at the location and system efficiency losses (MPPT conversion, wiring, temperature derating). Returns required wattage and common panel configurations.3 params

Calculate the required solar panel wattage to cover daily energy consumption. Accounts for peak sun hours at the location and system efficiency losses (MPPT conversion, wiring, temperature derating). Returns required wattage and common panel configurations.

Parameters* required

dailyConsumptionWh*number

Daily energy consumption in watt-hours (from calculate_power_budget)

peakSunHours*number

Average daily peak sun hours for the location. Examples: Northern Europe winter 1-2h, summer 4-6h. Southern US 5-6h. Equatorial regions 5-7h.

systemEfficiencynumber

Overall system efficiency factor (default: 0.85). Accounts for MPPT losses, wiring losses, temperature derating, and panel soiling.default: 0.85

calculate_charging_timeEstimate how long it takes to charge a battery bank from a given state of charge to a target level. Accounts for the bulk charging phase (constant current, up to ~80% SoC) and the slower absorption phase (tapering current, 80-100% SoC). Works for any charging source: solar, sh...6 params

Estimate how long it takes to charge a battery bank from a given state of charge to a target level. Accounts for the bulk charging phase (constant current, up to ~80% SoC) and the slower absorption phase (tapering current, 80-100% SoC). Works for any charging source: solar, sh...

Parameters* required

batteryCapacityAh*number

Total battery bank capacity in amp-hours

batteryVoltage*number

Battery bank voltage (e.g. 12, 24, 48)

chargeCurrentAmpsnumber

Maximum charge current in amps (if limited by the charger or battery BMS). If omitted, calculated from power and voltage.

chargePowerWatts*number

Charger output power in watts

currentStateOfChargePercent*number

Current state of charge in percent (e.g. 20 for 20%)

targetStateOfChargePercentnumber

Target state of charge in percent (default: 100)default: 100

calculate_inverter_sizeCalculate the recommended inverter size for running AC loads from a DC battery system. Accounts for continuous power, startup surge power (motors typically surge 2-3x), and includes a 25% headroom for the continuous rating. Returns the recommended inverter wattage and the DC c...2 params

Calculate the recommended inverter size for running AC loads from a DC battery system. Accounts for continuous power, startup surge power (motors typically surge 2-3x), and includes a 25% headroom for the continuous rating. Returns the recommended inverter wattage and the DC c...

Parameters* required

loads*array

List of AC loads that will run through the inverter

systemVoltage*number

DC system voltage (e.g. 12, 24, 48)

calculate_battery_configDetermine how to arrange batteries in series and/or parallel to achieve a target voltage and capacity. Returns the number of batteries needed, the wiring configuration (e.g. 2S3P), and step-by-step wiring instructions.4 params

Determine how to arrange batteries in series and/or parallel to achieve a target voltage and capacity. Returns the number of batteries needed, the wiring configuration (e.g. 2S3P), and step-by-step wiring instructions.

Parameters* required

singleBatteryAh*number

Capacity of one battery in amp-hours

singleBatteryVoltage*number

Nominal voltage of one battery (e.g. 12.8 for LiFePO4, 12 for lead-acid, 3.2 for LiFePO4 cells)

targetCapacityAh*number

Desired total capacity in amp-hours

targetVoltage*number

Desired system voltage (e.g. 12, 24, 48)

Configuration

VOLTPLAN_API_URL

URL of the VoltPlan API instance

Readme

VoltPlan Wiring Diagrams · MCP Server

I refit my boat with Claude as the electrician. Here's the MCP that made it possible.

An MCP server that gives Claude (or any MCP-compatible AI) domain expertise in 12V / 24V / 48V electrical systems — sizing the bank, picking the wire gauge, recommending the fuse, and generating a complete wiring diagram. For boats, campers, vans, and off-grid builds.

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

Drop that into your claude_desktop_config.json, restart Claude, ask: "Plan a 400 Ah lithium house bank for a 30 ft sailboat with 2 days of autonomy." Done.

Why this exists

View the full README on GitHub

Details

Repository: github.com/yuzu-hub/wiring-diagram-mcp
Website: voltplan.app
Category: Design & Creative
Package: wiring-diagram-mcp
Transport: STDIO, HTTP
Registry: MCP registry, active
Tools verified: Nov 6, 2026

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