Tesla
How Joulo connects a Tesla Wall Connector: Fleet API, OAuth, sync cadence and MID detection.
A Tesla Wall Connector connects through the Tesla Fleet API. You authorise Joulo once in your Tesla account. Joulo then reads charging history and live status on a schedule.
At a glance
| Property | Value |
|---|---|
| Route | Cloud API |
| API | Tesla Fleet API |
| Authentication | OAuth 2.0 with PKCE |
| Sync | Every 5 minutes |
| MID detection | Part number prefix 1529455-5 or 1529455-S2 |
| Backfill | Automatic, to 1 January 2026 |
How the connection works
Tesla runs the Fleet API in regional clusters. Joulo stores the region it authorised against and follows a 421 wrong-cluster response to the correct region. The new region is then persisted, so the redirect happens once.
Wall Connectors do not hang off a vehicle. They belong to an energy site, so live status and history come from the Energy Sites API rather than the vehicle endpoints. A Tesla account with no energy site therefore exposes no Wall Connector.
An expired access token is refreshed once with the refresh token before Joulo marks the integration as needing a reconnect.
What Joulo reads
Joulo reads the wall connector's charge history and its live state. Each history entry becomes one charging session with a start time, an end time and the energy in kWh.
MID certification
The Fleet API exposes no MID flag. The part number in the DIN is the only signal, so Joulo classifies on its prefix:
1529455-5…is the documented MID family.1529455-S2…is the 2026 production revision. Its type plate carries EN 50470-3, accuracy class 1(B) and the NMi metrology marking.
Any other prefix is a non-MID Wall Connector. Sessions still sync, and the charger stays out of ERE registration.
Limitations
- The Fleet API returns history, not a live meter stream. Energy for a running session updates on each tick, not continuously.
- A Wall Connector shared across two Tesla accounts must be authorised from the account that owns the energy site.