Webasto
Webasto Next and Unite EV Chargers: OCPP 1.6J and Modbus TCP Integration
Webasto (Gilching, Germany) — known for vehicle roof systems and heating — produces EV charging infrastructure with OCPP 1.6J/2.0.1 compliance. Webasto Next (residential 7.4 kW) and Webasto Unite (commercial 22 kW) offer straightforward KNX integration via OCPP local mode or direct Modbus TCP, making them suitable for smart building energy management.
Role in our panels
How we use Webasto
Webasto Next 7.4 kW single-phase: residential wallbox, IP54, cable attached (Type 2, 7.4m), OCPP 1.6J. Configuration via myWebasto app: Settings → OCPP → enter WebSocket URL (e.g. 'ws://192.168.1.50:9000/webasto'). Local OCPP server (Home Assistant OCPP integration): receives charger connection, reads StatusNotification and MeterValues messages (power W, energy Wh). HA automation writes active power to KNX GA via HA KNX integration. KNX binary output commands OCPP ChangeAvailability ('Inoperative') to pause charging for load management. Webasto Unite 22 kW three-phase: commercial charger, IP54, Type 2 socket or tethered cable, RFID, OCPP 2.0.1. Modbus TCP available on Unite firmware 2.x: port 502, unit ID 1. Registers (holding, FC3): 1001 (charge current setpoint, uint16, A, write — 0=disabled, 6-32A), 1002 (session energy, uint32, Wh, read), 1003 (active power, uint32, W, read), 1004 (charge state, uint16: 0=available, 1=preparing, 3=charging, 5=finishing). MDT Modbus Gateway: poll reg 1003 every 10s → KNX DPT 9.001 (kW). Poll reg 1004 → KNX DPT 5.010. Write reg 1001 from KNX logic for current setpoint (dynamic load management). Multi-charger: each Unite has unique IP → separate Modbus TCP connections in MDT gateway. Current balancing: KNX sums all active charger currents from reg 1004 status (charging=3) → distribute available capacity proportionally across active chargers. PV self-consumption: KNX reads PV surplus (from KOSTAL or Sungrow Modbus) → calculates available current → writes to Unite reg 1001.
Webasto Unite 22 kW communicates via Modbus TCP — KNX reads active power and charge state, and writes charge current setpoint for dynamic load management and PV self-consumption. Next 7.4 kW uses OCPP local mode via Home Assistant bridge.
Used in these project types
Webasto products
Key components we install
Webasto Next 7.4 kW residential
7.4 kW single-phase residential wallbox. IP54, Type 2 cable 7.4m, OCPP 1.6J. KNX integration via local OCPP server (Home Assistant) — reads active power (W) and controls charger availability. Suitable for villa and residential installations with PV self-consumption via Home Assistant bridge.
Webasto Unite 22 kW commercial
22 kW three-phase commercial charger. IP54, RFID, OCPP 2.0.1, Modbus TCP on port 502 (firmware 2.x+). Registers: active power (1003), charge state (1004), current setpoint write (1001). Used in office car parks, hotels, and apartment buildings for KNX dynamic load management.
Webasto Live 22 kW
22 kW three-phase charger with built-in dynamic load management (DLM) module. Suitable for multi-charger installations where internal DLM handles basic current balancing. KNX integration adds higher-level PV surplus coordination and building-wide load management.
Webasto Charger Home 11 kW
11 kW three-phase residential charger. OCPP 1.6J via Wi-Fi or Ethernet. KNX integration via Home Assistant OCPP local server for PV self-consumption control. Suitable for homes with three-phase grid connection requiring more than 7.4 kW charging speed.
Webasto FAQ
What are the Webasto Unite Modbus TCP port and unit ID?
Port 502, unit ID 1 (standard Modbus TCP). Requires Unite firmware version 2.x or later — earlier firmware only supports OCPP, not Modbus TCP. Check the firmware version in the myWebasto portal under device settings before specifying Modbus TCP integration.
What is the minimum charge current via Modbus write?
Write register 1001 = 0 to stop charging (charger goes to standby). Write 6 to restart at minimum 6A (1.38 kW per phase on three-phase). Values between 1-5 are invalid — the charger will not start below 6A. For single-phase Unite variants, minimum is also 6A.
Is RFID required for Unite commercial charging?
RFID reader is integrated but optional — the Unite can be set to 'Free Charging' mode in the myWebasto portal to allow any vehicle without RFID. OCPP 2.0.1 supports ISO 15118 Plug & Charge for future EV authentication without RFID, using the vehicle's own digital certificate.
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