How it works in one minute
Official
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)Volvo
(official integration)Home
Assistant
| What it is | An integration shipped with Home Assistant that reads Volvo Cars' public API |
| Cost | Free |
| Data | Battery level, capacity, electric range, charging state, target charge level, mileage, doors, windows, tyres, location |
| Commands | Preconditioning, locks; charging control isn't offered by the API |
| Where it works | Anywhere, through the car's connection (Europe, Middle East, Africa, Americas) |
| Depends on | Volvo's API and a developer key |
What you need
- Home Assistant installed and reachable from your computer.
- Your Volvo ID (the Volvo Cars app account), with the car on it.
- A free account on Volvo's developer portal, created with that same Volvo ID.
1Install the integration
- Create an application and its keyOn developer.volvocars.com, API applications page, create an application: the API key is shown. Use one key per car if you have several.
- Add the integrationSettings → Devices & services → Add integration, search for Volvo. With a Nabu Casa subscription, authorisation goes through Nabu Casa's account linking; otherwise, publish your application on the portal with the redirect address
https://my.home-assistant.io/redirect/oauth, then enter its credentials in Home Assistant. - Allow access and paste the keySign in with your Volvo ID in the window that opens, accept, then paste the API key from step 1.
- Find the carThe car appears as a device under Settings → Devices & services → Volvo.
Its author joined Home Assistant: the official integration replaces it. Remove the old one before adding the new one.
2The data you get
| Data | What it's for |
|---|---|
| Battery | Level in %, the value to give Watt Budget |
| Battery capacity | In kWh |
| Distance to empty battery | Electric range |
| Charging state | Charging, plugged in, done |
| Target battery charge level | As set in the car |
| Doors, windows, tyres | For an evening alert |
Replace the long names with short ones, for example sensor.ex30_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 sensor (in %) of the Volvo 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
- The primary and secondary keys shown on the portal share the same daily request limit: don't use the same application for several tools.
- If the integration often asks you to sign in again, check the same key isn't used for two cars.
- 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
My Volvo is in Australia. Does it work?
Not yet: Volvo's API covers Europe, the Middle East, Africa, the US, Canada and Latin America.
Can I start or stop charging?
No, Volvo's public API doesn't allow it for now. Control the charger from Home Assistant instead.
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 Thomas D. (thomasddn), author of the Volvo Cars integration and then of the official one.
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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