MyGrid ModuleTwo & VoltBridge: local MQTT Discovery, battery control and energy monitoring

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Hi everyone,

I’m Jan, founder of MyGrid, a Belgian team developing plug-in home batteries. I’d like to share our Home Assistant support for ModuleTwo and our VoltBridge P1 smart-meter reader, and hear your feedback.

ModuleTwo is a modular LiFePO₄ home battery, expandable from 2.11 to 10.55 kWh. We believe users should be able to choose between our built-in energy management and their own Home Assistant automations.

Both devices connect directly to an MQTT broker on your home network. Home Assistant discovers their entities through its standard MQTT integration, without manually defining them in YAML. Once configured, the local MQTT connection continues working if your internet connection drops.

GitHub repository and documentation:
MyGrid-Energy/mygrid-homeassistant-mqtt

With ModuleTwo, you can:

  • Monitor battery charge level, power and stored energy.

  • Add cumulative charged and discharged energy to the Home Assistant Energy dashboard.

  • Set charging and discharging power after explicitly enabling Home Assistant control.

VoltBridge provides grid import/export totals and net power. Depending on what your meter supplies, it also exposes phase measurements, gas consumption and Belgian capacity-tariff demand values. VoltBridge readings update approximately once a minute.

To connect a device:

  1. Set up a local MQTT broker, such as Mosquitto, and connect Home Assistant’s MQTT integration to it.

  2. In the MyGrid Energy app, open the device and go to Features → Home Assistant.

  3. Enter your broker’s local IPv4 address, port and credentials if required.

  4. Enable Home Assistant, apply the settings and wait for Connected. The device’s entities should then appear under MQTT in Home Assistant.

Enabling MQTT initially shares monitoring data. To automate the battery, select Control → Home Assistant control in the MyGrid app. This enables the writable power setpoint: positive watts charge the battery, negative watts discharge it, and zero means idle. Select MyGrid Smart Control to return to automatic operation.

One behaviour to account for in your automations: if Home Assistant or the broker stops, ModuleTwo retains its last power setpoint, subject to the battery’s operating limits and protections.

The documentation includes:

If you’re using either device, we’d love to see your dashboards and automations and hear what could work better. Questions and suggestions are welcome here, and you can report issues through GitHub Issues.