Genmon Generator Monitor — Home Assistant Integration

A native Home Assistant custom component for monitoring and controlling Generac generators via genmon.

This integration communicates with the genhalink addon running on your genmon instance, providing real-time generator data through a REST + WebSocket API. It works alongside the existing MQTT-based integration — users can choose whichever fits their setup.

Features

• 60+ sensors: Battery voltage, RPM, output power, fuel level, run hours, weather, and more
• 8 binary sensors: Outage detection, generator running, alarm active, utility present, etc.
• 5 control buttons: Start, Stop, Start Transfer, Start Exercise, Set Time
• Quiet mode switch: Toggle quiet mode for Evolution/Nexus controllers
• Exercise scheduling: Select day/frequency and set hour/minute via HA UI
• Automatic discovery: Zeroconf/mDNS finds your generator on the network
• WebSocket push updates: Near-instant state changes without polling delay
• HACS compatible: One-click install via the Home Assistant Community Store
• Diagnostics: Built-in diagnostics download for troubleshooting
• Multi-instance: Supports multiple generators

Requirements

• genmon running on a Raspberry Pi (or similar) connected to your Generac generator
• genhalink addon enabled in genmon (see setup below)
• Home Assistant 2024.1.0 or later

Installation

Option 1: HACS (Recommended)

1. Open HACS in Home Assistant
2. Click the three dots menu → Custom repositories
3. Add https://github.com/jgyates/genmon-ha with category Integration
4. Search for "Genmon Generator Monitor" and click Download
5. Restart Home Assistant

Option 2: Manual

1. Copy the https://github.com/jgyates/genmon-ha/custom_components/genmon/ folder to your Home Assistant config/custom_components/ directory
2. Restart Home Assistant

Setup

Step 1: Enable the genhalink addon in genmon

1. Open the genmon web UI (typically http://<pi-ip>:8000)
2. Go to Settings (gear icon)
3. Find Home Assistant Integration (Native) and enable it
4. An API Key is automatically generated — copy it for the next step
5. Optional: Enable Zeroconf for automatic discovery
6. Click Save and the addon will start automatically

Step 2: Add the integration in Home Assistant

Automatic Discovery (if Zeroconf is enabled)

1. Home Assistant will automatically discover your generator
2. A notification will appear — click Configure
3. Enter the API Key from Step 1
4. Click Submit

Manual Setup

1. Go to Settings → Devices & Services → Add Integration
2. Search for Genmon
3. Enter:
   • Host: IP address of your genmon Raspberry Pi
   • Port: 9083 (default)
   • API Key: The key from Step 1
4. Click Submit

Options

After setup, you can configure options via the integration's Configure button:

Option	Default	Description
Polling interval	5 seconds	Fallback polling rate. WebSocket push updates are always active.
Include monitor stats	Yes	Include CPU usage, comm stats, and other platform metrics
Include weather	Yes	Include weather sensors (if configured in genmon)
Excluded sensor paths	(empty)	Comma-separated genmon data paths to skip

Entities

Sensors

Entity	Description	Device Class
Battery Voltage	Generator battery voltage	voltage
RPM	Engine RPM	—
Output Frequency	Generator output frequency	frequency
Output Voltage	Generator output voltage	voltage
Output Current	Generator output current	current
Output Power	Single-phase output power	power
Power Leg 1/2	Per-leg power (split-phase)	power
Current Leg 1/2	Per-leg current (split-phase)	current
Engine State	Current engine state text	—
Switch State	Transfer switch position	—
Utility Voltage	Incoming utility voltage	voltage
Fuel Level	Tank fuel level (%)	—
Estimated Fuel	Gallons remaining	—
Total Run Hours	Lifetime run hours	duration
Energy (30 Days)	kWh generated in last 30 days	energy
Weather Temperature	Local weather temp	temperature
...and many more	Dynamic sensors auto-discovered from your controller	—

Binary Sensors

Entity	Description
System In Outage	Utility power lost
Generator Running	Engine is running
Exercising	Currently in exercise mode
Alarm Active	Active alarm present
Utility Power Present	Utility power available
Switch in Auto	Transfer switch in auto mode
Update Available	Genmon update available

Controls

Entity	Type	Description
Start / Stop	Button	Remote start/stop generator
Start Transfer	Button	Start with transfer
Start Exercise	Button	Trigger exercise cycle
Set Generator Time	Button	Sync generator clock
Quiet Mode	Switch	Toggle quiet mode (Evo/Nexus)
Exercise Frequency	Select	Weekly/BiWeekly/Monthly
Exercise Day of Week	Select	Day selection for exercise
Exercise Hour/Minute	Number	Time of day for exercise

Native vs MQTT Integration

Feature	Native (genhalink)	MQTT (genhomeassistant)
Setup	Direct connection	Requires MQTT broker
Discovery	Zeroconf automatic	MQTT Discovery
Updates	WebSocket push + polling	MQTT publish on change
Latency	~instant	Depends on broker
Dependencies	genhalink addon	MQTT broker + addon
Config flow	Full HA config UI	Manual MQTT setup
Diagnostics	Built-in	—

Both integrations work independently. You can use either or both simultaneously.

Troubleshooting

Cannot connect

• Verify genmon is running: http://<pi-ip>:8000
• Verify genhalink addon is enabled in genmon Settings
• Check the port (default 9083) is accessible from your HA instance
• Check firewall rules on the Pi: sudo ufw allow 9083/tcp

Invalid API key

• Open genmon Settings → Home Assistant Integration (Native)
• Copy the current API key and re-enter it in HA

Missing entities

• Some entities are controller-specific (Evolution, Nexus, H-100, PowerZone)
• Check Options → "Include monitor stats" / "Include weather" toggles
• Dynamic sensors appear after the first data poll

Check genhalink logs

On the genmon Pi:

tail -f /var/log/genhalink.log

License

This integration is part of the genmon project and is distributed under the same license.