Silla Prism

The Silla Prism integrationIntegrations connect and integrate Home Assistant with your devices, services, and more. [Learn more] lets you monitor and control a Silla Prism electric vehicle wallbox from Home Assistant over its native MQTT protocol. Silla is an Italian manufacturer of EV charging equipment.

Prerequisites

This integration communicates with the Prism through an MQTT broker; the wallbox itself acts as an MQTT client. Before adding it, you need:

1. The MQTT integration set up in Home Assistant with a broker.
2. MQTT enabled on the Prism, pointed at the same broker. Configure it in the Silla app, under the device’s MQTT settings, and note the base topic (the default is prism).

The base topic is configurable in the Silla app, so it can differ between installations. Whatever value you set there must match the one Home Assistant uses.

Configuration

To add the Silla Prism device to your Home Assistant instance, use this My button:

When the Prism reconnects to the broker, it announces itself and Home Assistant offers to set it up automatically. Automatic discovery only works when the base topic is left at its default value (prism), because the discovery topic is fixed. If you changed the base topic in the Silla app, add the integration manually and enter that topic instead.

To use more than one Prism, give each unit its own base topic in the Silla app, then add each one separately. Units that share the same base topic publish to the same MQTT topics and cannot be told apart.

Supported functionality

The integration creates a single device with the following entities.

Sensors

• Status: The charging state of the port (idle, waiting, charging, or paused).
• Power: Power currently delivered to the vehicle.
• Current: Current currently delivered to the vehicle.
• Voltage: Measured line voltage.
• Pilot current: Current signaled to the vehicle over the control pilot.
• Session energy: Energy delivered during the current charging session.
• Total energy: Lifetime energy delivered by the Prism.
• Session start: When the vehicle was connected. The Prism only reports the elapsed session time, once a minute, so Home Assistant derives the start time from it. The frontend then shows a duration that stays accurate between updates. It is unknown while no vehicle is connected, and the clock keeps running while charging is paused.
• Error: The fault reported by the port. The Prism MQTT protocol only documents the “no error” condition, so any other code is reported as unknown.
• Temperature: Internal temperature of the Prism.
• Grid power: Power drawn from the grid. Positive values are imports, negative values are exports.

Data updates

The Prism pushes an MQTT message whenever a value changes, so entities update in real time. Status topics are retained on the broker, so Home Assistant restores the current values immediately after a restart. The session time is the exception: the Prism publishes it without the retain flag, about once a minute, so the session start sensor stays unknown for up to a couple of minutes after a restart.

Known limitations

• The integration currently provides read-only sensors. Setting the charging current and changing the charging mode are not available yet.
• Only the first charging port is supported. On a Prism DUO, the second cable is not exposed.
• The current limit used for custom load balancing, the night schedule, and charge authorization are not exposed yet.
• Solar and home power flows are only meaningful when a Powerwall or compatible meter is configured on the Prism; otherwise they report 0.

Removing the integration

This integration follows standard integration removal. No extra steps are required.

To remove an integration instance from Home Assistant

1. Go to Settings > Devices & services and select the integration card.
2. From the list of devices, select the integration instance you want to remove.
3. Next to the entry, select the three dots menu. Then, select Delete.