How it works in one minute
HACS
It was written in October 2026 from the integration's official documentation, but nobody in the Watt Budget community has followed it end to end on their car yet. Trying it? Tell me what works and what gets stuck.
(car's 4G)Polestar API
(HACS integration)Home
Assistant
| What it is | A community integration that reads your Polestar account's data |
| Cost | Free |
| Data | Battery level, range, charging state, time left, mileage, vehicle information |
| Commands | None: read-only |
| Where it works | Anywhere, through the car's connection |
| Depends on | Polestar's servers and your Polestar ID |
What you need
- Home Assistant installed and reachable from your computer.
- HACS, the community store for Home Assistant extensions (installation explained on hacs.xyz).
- Your Polestar ID (the Polestar app's email and password). Check it works on Polestar's login page.
1Install the integration
- Install the integrationIn HACS, search for “Polestar API”, click Download, then restart Home Assistant.
- Add itSettings → Devices & services → Add integration, search for Polestar API.
- Sign inEnter your Polestar ID's email and password.
- Find the carThe car appears as a device under Settings → Devices & services → Polestar API.
Depending on the model, Polestar doesn't return all data: some sensors stay empty. The developers can't fix it and encourage owners to ask Polestar for a public API.
2The data you get
| Data | What it's for |
|---|---|
| Battery level | In %, the value to give Watt Budget |
| Estimated range | In kilometres |
| Charging state and cable | For an automation when you get home |
| Charge time left | While charging |
| Mileage | For your stats |
| Vehicle information | Model, software, service due |
Replace the long names with short ones, for example sensor.polestar_battery (Settings → Devices & services → Entities → the entity → cog). Your cards, automations and Watt Budget settings will be much easier to read.
3Connect Watt Budget
The sensor to enter in Watt Budget, under Settings › Home Assistant: the battery level sensor (in %) of the Polestar device.
Once connected, Watt Budget reads the level every minute: no more typing the starting percentage, and the charge is worked out from the real battery level.
The four steps (HTTPS access, token, sensors, check) are explained on the guides home page and in the Watt Budget guide.
4Precautions
- Values can lag a little: the car only sends them at certain moments.
- Unofficial integration: the manufacturer can change its app and break it overnight. Keep the official app on your phone.
- Don't shorten the update interval: each query can wake the car and drain its 12 V battery. The defaults are a good balance.
- Your credentials stay in your Home Assistant; neither Watt Budget nor I can see them.
Frequently asked questions
Can I start the climate?
No, the integration is read-only. Keep the Polestar app for commands.
Is the Polestar 4 supported?
It uses the same account, but some data may be missing. The battery level is enough for Watt Budget.
Does Watt Budget get access to my car?
No. Watt Budget only reads the battery level sensor in your Home Assistant, from your browser, with the token you give it. It never sees your manufacturer login or the car's location.
My model isn't listed. Can it work?
Often yes: these integrations go through the manufacturer's app, shared across the range. The easiest is to try, then tell me how it went via the contact page.
Links and thanks
Thanks to the pypolestar team, who maintain the integration and its translations.
Does your car reach Home Assistant another way? Share your method: the next guides will follow your feedback.
The other Home Assistant guides
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