[Custom Integration] ABB Terra AC EV Charger (Modbus TCP)

[JernejHren]

ABB Terra AC — Release Notes v0.2.0

Upgrade Notice

After upgrading from v0.1.x, a duplicate “ABB Terra AC Charger” device will appear in Home Assistant. The old device (with no entities) can now be deleted via Settings → Devices & Services → ABB Terra AC Modbus → old device → Delete. This is a one-time migration — future upgrades will no longer cause duplicate devices.

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New Features

• Orphaned device removal — Home Assistant now allows deleting old or duplicate charger devices directly from the UI.
• Fallback limit restored to last known valid value — Previously, the fallback limit was always reset to a hardcoded 6A after a firmware bug triggered an invalid value. It is now restored to the last known valid value set by the user.
• Fallback limit minimum set to 0A — The fallback limit slider now allows 0A as a minimum value. Setting 0A triggers a pause state on communication loss, allowing the charging session to resume automatically once communication is restored.
• Charging current slider maximum is now dynamic — The maximum value of both the charging current and fallback limit sliders now reflects the user_settable_max_current register from the charger, which represents the maximum current configured in the Terra Config app.

Improvements

• Full English codebase — All code comments, log messages, and docstrings have been translated to English, making the integration more accessible to the wider Home Assistant community. A Slovenian translation remains available for the UI.
• Robust Modbus client close — Both __init__.py and config_flow.py now use a safe close helper that correctly handles different pymodbus versions regardless of whether close() is awaitable or not.
• Stable device identifier — The charger device is now identified by the config entry ID instead of the serial number, preventing duplicate devices on future upgrades.

[borsa93]

Hi, is it possibile to have two wallbox Connected with RS485 to the same Rs485 to eth device? (an unique integration, with slave 1 and slave 2).
Thanks for the support.

[Thinko]

For using with this integration you must have charger WITH LCD and own IP addres. So you add IP of your charger to this APP.
Or IP TCP RS485 module. You buy Modbus with more inputs with own IP RS
input

2-CH RS485 TO ETH (B) - Waveshare Wiki

[borsa93]

Thanks for your answer First of all. I followed instructions written above (with DR134 adapter). It works fine but just for one wallbox even of rs485 has been Connected in both wallbox. Is it there the possibility to have both instances on home assistant with an unique adapter?
Thanks

[Thinko]

dual input rs485 tcp. With this APP charger is only MASTER

[JernejHren]

It should be possible to add multiple chargers, but every charger must have its own IP, integration connects to. But integration “only” connects charger to home assistant. It does not manage your charging. For managing charging you must set up automations or integration.

[JernejHren]

[Test Request] ABB Terra AC Integration - Complete Rewrite (Focus on Quality Scale)

Hi everyone,

I’ve been working on a significant update for the ABB Terra AC integration. I have just pushed a new branch to my GitHub repository, and I’m looking for some brave souls to help me test it before it goes into the official release.

GitHub Branch: GitHub - JernejHren/ABB-Terra-AC at lmm · GitHub

What’s New?

This isn’t just a small patch—it is a complete rewrite of the integration. With the help of AI, I have refactored the entire codebase to align with the Home Assistant Quality Scale guidelines.

The goal was to make the integration more robust, efficient, and easier to maintain long-term.

Current Status:

• Stability: I have been running this new version for 2 days now without any issues.
• Performance: All sensors and controls for the charger are reporting correctly.
• Safety: Before I merge this into the main release, I want to ensure it works across different environments and charger firmware versions.

How to Help:

If you have an ABB Terra AC charger, please try out the lmm branch. You can manually replace the files in your custom_components folder (don’t forget to backup first!).

I am specifically looking for feedback on:

1. Discovery/Initial Setup: Does the integration load correctly?
2. Entity Stability: Do any entities go “unavailable”?
3. Logs: Do you see any new errors or warnings in the HA logs?

Please leave your feedback here or open an issue on GitHub. Thanks for your help in making this integration better for the community!

[llerda]

Dear Glajci. I want to connect my Terra AC wallbox to Home Assistant. I use Wifi to manage the wallbox using ABB Mobile App. Are you using RS482 Modbus to WiFi converter to connect Wallbox to local home asssitant ? Which converter you bought ? Thanks

[Thinko]

wired or wifi any rs485 modbus. i use USR-DR134 RS485 or USR-DR164 from aliexpres.

[b0ll0s (Mathijs)]

Ive just ordered the modbus; as soon as it is in ill try the integration from scratch and share my feedback!

Thanks for this development!

[JernejHren]

I just released version 0.3.1.

Removed the on/off switch and replaced it with Start Charging and Stop Charging buttons.

[desIllution]

Thank you for the update @JernejHren.

ABB Terra AC Charger 0.3.2 is currently running with DR134 (as descibed above) and Terra AC (TAVW0-4/FW 1.8.36, polling interval 30s / HA Core 2024.4.1 / Supervisor 2026.03.3 / OS17.2).

I realised that the status of the variabled from the implementation (e.g. charging state) changes to “not available” each ~10 minutes. On the next polling interval the status is back online. Ping of DR134 is always “online”. Someone else sees this topic (might also be related to the DR134)?

Error log:

Logger: custom_components.abb_terra_ac
Source: helpers/update_coordinator.py:497
Error fetching abb_terra_ac data: Modbus Error [Input/Output] Request cancelled outside pymodbus

and

Logger: custom_components.abb_terra_ac
Source: custom_components/abb_terra_ac/__init__.py:168
Unexpected error: Modbus Error: [Input/Output] Request cancelled outside pymodbus

Traceback: 
File: "custom_components/abb_terra_ac/__init__.py:168" in _async_update_date
  result = await asyncio.waitfor(
           ^^^^^^^^^^^^^^^^^^^^^^
    ...<2 lines>..
    )
    ^

@JernejHren: Is an udate of EVSCI missing on GitHub? The only change between 0.1.3 → 0.2.0 seems to be the version in the manifest.

Thank you and a sunny day.

[Thinko]

Have same problem:
On modbus you must have: Working protocol: SIMPLE MODBUS PROTOCOL

[JernejHren]

I updated files on EVSCI integration.

As thinko said when new version 0.3.0 or newer is used with tcp/rs485 converter it looks like modbus protocol must be set to simple modbus protocol.
Do you use converter?

[JernejHren]

V0.3.3. released
Release notes (EN)

• Fixed intermittent pymodbus errors like Request cancelled outside pymodbus by avoiding external asyncio cancellations around Modbus requests.
• Serialized Modbus operations with a shared asyncio.Lock to prevent overlapping reads/writes on the same TCP client.
• Added automatic reconnect and a single retry for coordinator polling reads after transient I/O failures.
• Applied the same resilient Modbus call path to the config flow probe and to entity write helpers.
• Added tests covering ModbusIOException handling and reconnect+retry behavior.

[desIllution]

@desIllution

Dear collegues,
first of all - thank you JernejHren et al for this great implementation.

I want to share to the community how I successfully integrated the Wallbox without LCD (ABB Terra AC / 6AGC082156) into HA. As already mentioned, you need a Modbus TCP interface.

I used the DR134 having a LAN interface, can be bought at ali… and configured it as followed:

• enable “local controller - Modbus RTU(RS485)” in the Terraconfig App. I set modbus-Adress to 1 and Baudrate to 57600.
• Connect the DR134 to the Terra AC with RS485 A->A and B->B. I used a 20cm shielded cable, shield to GND at charger. No termination.
• EDGE Gateway: Working Mode: Modbus Multi Host Poll

Note for implementation > V0.3.x: Setting “EDGE Gateway” on DR134 to Working Mode “Modbus Simple Protocol” resolved the issue, thanks for the input. I have also added 120E termination resistor I have now a long cable form Terra AC to DR134.

[CasaPagano]

Good morning, I have an ABB Terra WIFI wallbox, but I’m far from a LAN network and I’m having trouble powering new devices. Is there a way to integrate the charger into Home Assistant using the ChargerSync app? Or can you explain a simple way to connect everything, even with the various wiring to be done, but without powering devices, just connecting them to the terminals already present on the wallbox? Thank you very much.

Buongiorno, io ho wallbox Terra ABB WIFI ma sono distante da rete LAN e ho difficoltà ad alimentare nuovi dispositivi. C’è un modo per integrare il caricatore in Home Assistante sfruttanto l’APP ChargerSync??? Oppure mi spiegate un modo semplice per collegare il tutto anche con i vari cablaggi da fare ma senza dispositivi da alimentare ma solo eventualmente da collegare ai morsetti già presenti nella WallBox? grazie mille

[JernejHren]

If you want to use original wifi your only option is OCPP integration.

[CasaPagano]

Thank you. Could you explain the procedure for configuring the WallBox for OCPP because I can’t enter the required parameters from the ChargerSync app. Should I use another app? Is anyone using OCPP for the ABB Terra wallbox? Thanks everyone.

Grazie potresti spiegarmi la procedura per configurare la WallBox per OCPP perchè da App ChargerSync non riesco ad inserire i parametri richiesti. Devo usare altra App? C’è qualcuno che usa OCPP per la wallbox Terra ABB? Grazie a tutti

[JernejHren]

No. Haven tested it. You should ask on their forum.