MeterLink C3
MeterLink C3
Bring your Kamstrup OMNIPOWER meter into Home Assistant—locally
MeterLink C3 is a compact Wi‑Fi communications module that connects a compatible Kamstrup OMNIPOWER electricity meter to your local Home Assistant installation.
It reads encrypted DLMS/COSEM data directly from the meter’s HAN interface, decrypts it locally and publishes the measurements through MQTT. No cloud service, subscription or external data provider is required.
Available measurements
Depending on the meter configuration, MeterLink C3 exposes:
- Imported and exported energy
- Current import and export power
- Voltage on all three phases
- Current on all three phases
- Import and export power per phase
- Wi‑Fi signal strength
- HAN and communication health
- Firmware and diagnostic information
Home Assistant MQTT Discovery creates the supported entities automatically.
Designed for local operation
All meter data remains on your local network. MeterLink C3 communicates directly with your MQTT broker and does not depend on an external cloud platform.
A built-in web interface provides:
- Live meter readings
- Wi‑Fi, MQTT and HAN connection status
- Stored-energy and power-source information
- Configuration backup and import
- Secure, signed firmware updates
- Troubleshooting diagnostics
Intelligent power management
MeterLink C3 is designed around the limited power available from the meter’s HAN interface.
An internal supercapacitor stores energy for short Wi‑Fi current peaks. The module automatically adjusts its operating profile according to its power source:
- On HAN power, Wi‑Fi remains connected while power-saving features reduce average consumption.
- When USB is connected, MeterLink C3 switches to full-performance operation.
- Firmware updates temporarily enable the required radio performance and are permitted only when sufficient stored energy is available.
USB and HAN power are isolated through an automatic power-selection circuit to prevent one source from feeding into the other.
Compatibility
Designed for:
- Compatible Kamstrup OMNIPOWER electricity meters
- The six-pin, 2×3, 2.54 mm HAN connector
- Encrypted DLMS/COSEM Push1 telegrams
- 2.4 GHz Wi‑Fi networks
- MQTT brokers, including the Home Assistant Mosquitto add-on
- Home Assistant installations with MQTT Discovery enabled
Your electricity network operator must activate the HAN interface and provide the meter-specific encryption and authentication keys.
Compatibility depends on the meter model, firmware, connector and HAN configuration. Check these details before ordering.
Installation overview
- Obtain the two HAN encryption keys from your network operator.
- Configure Wi‑Fi, MQTT and meter keys through the setup interface.
- Disconnect USB and insert MeterLink C3 into the meter’s HAN socket.
- Allow the internal energy reservoir to charge.
- Find MeterLink C3 under Home Assistant’s MQTT devices.
The product should only be installed in an accessible, authorized HAN socket. Do not open the sealed or mains-voltage section of the electricity meter.
Privacy and security
- Local-only meter-data processing
- No mandatory cloud account
- No subscription
- Per-device administration password
- Authenticated configuration interface
- Cryptographically signed firmware updates
- Meter keys stored on the device
Plain MQTT should only be used on a trusted local network. MQTT TLS can be configured when supported by your broker.
Package contents
- MeterLink C3 communications module
- Integrated HAN connector
- Internal supercapacitor energy reservoir
- Quick-start and safety guide
Electricity meter, USB cable, MQTT broker and Home Assistant hardware are not included.
Important notice
MeterLink C3 is an independent product and is not manufactured, endorsed or supported by Kamstrup A/S or the Home Assistant project. Kamstrup and OMNIPOWER are trademarks of their respective owner. Home Assistant is a trademark of the Open Home Foundation.
MeterLink C3
Your electricity meter. Your local data. Your Home Assistant.