BYD Auto → Home Assistant via MQTT

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1

Hey all,

Wanted to share a project for anyone else who happens to live at the intersection of “owns a BYD” and “runs Home Assistant” — I know, it’s a narrow slice of the Venn diagram, but if you’re here, welcome, we’re a small club.

Since BYD (via the BYD Auto Link app) doesn’t offer a public API, I built a tool that gets telemetry out anyway using UI automation, and pushes it into Home Assistant over MQTT.

GitLab: https://gitlab.com/Spudmn/byd_auto_data_extractor

How it works

Since there’s no supported API, the tool drives the actual BYD Auto Link Android app using Appium and reads whatever’s on screen — same as a human would. It runs unattended on a spare/old Android phone connected to a home server or NUC, walks through the Home, Status, and AC screens on a schedule (plus a best-effort attempt at pulling location out of the in-app Google Maps view), and publishes what it finds to an MQTT broker.

A scheduler process runs it on a loop and adjusts how often based on the car’s driving status — polling more often while the car’s active, and backing off when it’s shut down, so it’s not hammering the app all day for no reason. It also listens for MQTT commands so you can wake it early on demand.

What you get in HA

  • Vehicle status and general home-screen data
  • AC/climate status
  • Rough location (via Maps UI scraping — best-effort, can fail if Maps switches to nav mode mid-read)
  • Whatever else the phase scripts pull off the Home/Status/AC screens

Setup basics

  • Old Android phone with the BYD Auto Link app, PIN-unlockable, plugged in via USB to a PC/NUC
  • Appium + Python 3
  • MQTT broker
  • Config is a .env file with your device name, app PIN, and MQTT broker settings

Heads up

This isn’t using any private/internal API — it’s purely reading what’s visibly shown in the official app, so it’s not affiliated with or endorsed by BYD in any way. It’s GPL-3.0 licensed, so feel free to dig in, fork it, or send improvements. Since it depends on the app’s UI, future app updates may require selector tweaks on my end (or yours, PRs welcome).

A couple of things are still rough edges: the Seat phase isn’t implemented yet, and Location is wrapped in a try/except because Maps’ UI can shift out from under the scraper mid-read.

2

This is awesome, and I love your effort as the whole lack of public API has been frustrating!
Are you aware of this integration for HA (GitHub - jkaberg/hass-byd-vehicle: Custom HASS integration for BYD vehicles. · GitHub)?

3

Thanks for the heads up!
I hadn’t come across that one - I’ll take a look at how they’re handling things.
Appreciate you flagging it.

4

I’m commenting on your approach, not the content. Identifying fields to match up and export from one platform to another is hard work and many long hours - I acknowledge that. Hunting through Chinese documentation can also be a chore, especially if it is not your native language. A well documented API would be oh so welcome!

How many spare Android phones do you have? Do they have to have a minimum Android level to provide the behind-the-scenes Android, js and Web Services calls that Appium may depend on?

This is not the first UI screen scraper you have recently published. See Halo Chlor GO (AstralPool Chlorinator) → Home Assistant via MQTT
Yes, it is a screen scraper, regardless of how you spin it. It’s just you are running it on an Android platform using Appium as your screen scraper tool.

A ‘spare Android phone’ involves an old battery, and unless you have the appropriate maintenance regime to support keeping that charged appropriately, you have safety issues, especially if it is unattended while you are driving around in your BYD.

You are using the Android platform as a screen scraper platform, an intermediate hardware step that could possibly be performed as an add-on app in software on the HomeAssistant server. Not to say it doesn’t work, it just seems an inelegant way to achieve your goals. You also need to have your BYD SeaLion updating the cloud in real time to be able to scrape the data using your Appium server. A lot of traffic floating around.

Should you wish to go ‘native’, the HomeAssistant developer docs are found at https://developers.home-assistant.io/

Are you using AI to churn these out? If so, it might be a simple ask to attempt to port to a HACS style software virtual environment instead of the Android hardware platform. The pyBYD work already on GitHub can be harnessed to add your functionality, especially as you have independently done so much reverse engineering to date. In the spirit of Open Source, some collaboration with ideas for ongoing development may prove beneficial to all.

You may find some issues discussed in GitHub that might change your approach, such as constant polling from your server possibly draining the BYD Battery, preventing it going into Deep Sleep mode. See API mapping collaboration · Issue #20 · jkaberg/pyBYD · GitHub

You constantly say BYD has no public API. What if they relent and release one? How easily could it slot into your solution?