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)MercedesME 2020
(HACS integration)Home
Assistant
| What it is | A community integration that logs in to Mercedes me like the app |
| Cost | Free |
| Data | Battery level, range, charging, power, charge end, mileage, doors, windows, tyres, location |
| Commands | Pre-climate, locks, charge limit, depending on the model and PIN |
| Where it works | Anywhere, through the car's connection |
| Depends on | Mercedes's servers and your account |
What you need
- Home Assistant installed and reachable from your computer.
- HACS, the community store for Home Assistant extensions (installation explained on hacs.xyz).
- The Mercedes me (Mercedes-Benz) app used at least once with the car before installing the integration.
- A separate Mercedes me account, invited to the car by the main account (up to six users per car). Two-factor authentication must be off on that account.
- The app's PIN, for some commands.
1Install the integration
- Prepare the dedicated accountCreate a new Mercedes me account, then invite it to the car from the main account. Use it only in Home Assistant: never at the same time in the app.
- Install the integrationIn HACS, search for “MercedesME 2020”, click Download, then restart Home Assistant. Also refresh your browser page after the restart.
- Add itSettings → Devices & services → Add integration, search for MercedesME 2020, pick the Europe region and sign in with the dedicated account.
- Find the carThe car appears as a device under Settings → Devices & services. In the options you can enter the PIN and exclude cars.
Some data, like geofencing, is only sent to the main account. If you need it, use the main account in Home Assistant and the secondary one on your phone.
2The data you get
| Data | What it's for |
|---|---|
| Battery level | In %, the value to give Watt Budget |
| Electric range | Estimated kilometres |
| Charging, power, charge end | While charging |
| Charge limit | Depending on the model |
| Mileage | For your stats |
| Doors, windows, tyres, locks | For an evening alert |
Replace the long names with short ones, for example sensor.eqa_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 (state of charge, in %) of the Mercedes 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
- To reduce the risk of an account block, never use it in Home Assistant and in the app at the same time.
- Smart cars no longer report any data this way since January 2025.
- 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
Login fails though the password is right. Why?
Most often, two-factor authentication (MFA) is on for the account: it isn't compatible. Use a dedicated account without MFA.
Is my Smart #1 or #3 supported?
No: Smart data has no longer been available through Mercedes me since 6 January 2025.
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 René Nulsch, author and maintainer of MercedesME 2020 for years.
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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