Watt Key

Watt Key is an app for Android Wear OS smart watches. It connects directly to your Tesla via Bluetooth Low Energy and allows you to use your watch as a key fob that can automatically unlock your Tesla as you approach.


  • Automatically lock/unlock your car as you walk towards/away from it
  • Manually lock/unlock
  • Open the frunk
  • Open and close the trunk
  • Open and close the charge port
  • Quick access tile
  • Support for adding multiple Tesla's

How to Connect to Your Tesla

When you first open Watt Key it'll present you with a small tutorial on how to do this. Once you follow this tutorial or skip it you'll be presented with a request to allow the app to use Location/Bluetooth permissions. You must accept this request so Watt Key can access the watch's Bluetooth. After accepting you'll see a list appear and your watch will begin scanning Bluetooth for nearby Tesla's.

If you're near your Tesla you should see it come up on this list. Tesla's are listed by their Bluetooth name given to them by Tesla. This Bluetooth name is a representation (SHA1) of the Tesla's VIN. If there's multiple Tesla's around you it may be difficult to figure out which is yours. To help you can look at the signal strength indicator listed for each Tesla, the one with the strongest signal should be the Tesla you're standing closest to. You can also manually enter your Tesla's VIN so Watt Key can connect directly to it.

Once you've pressed on your Tesla or manually entered the VIN, Watt Key will generate a cryptographic key that it'll use to authorize itself with your car. On completion it'll start connecting to your Tesla and request to be added to your Tesla as a key. Your Tesla requires you to authorize this by swiping your NFC key card on either the door pillar or on the center console. Watt Key will prompt you to do this when the Tesla asks for permission. After swiping your key your watch will now be added as a key in the Locks section of the Car menu!

How is Watt Key Different From Watt Time?

Watt Key uses Tesla's VCSEC Bluetooth protocol to communicate with the Tesla vehicle itself. This requires no internet connection. Bluetooth is a very fast protocol and all commands sent will be immediate. The Bluetooth protocol however only allows for basic commands like lock/unlock, open/close frunk, trunk and charge port.

Watt Time on the other hand uses the Tesla API which requires an internet connection. This comes with the usual downsides of an internet connection, it can be slow or unavailable all together, also on rare occasions the Tesla API server goes down and no one is able to access their vehicle via the Tesla app and by proxy, Watt Time.