kWhKey
Your car on your phone and your watch.
kWhKey is a fast, private companion app for your Tesla, for Android phones and Wear OS watches.
$4.99 per car a month, or $199.99 once. The watch app is included.
Model 3 ⇄ Model Y - one app, every car in the household, the watch follows
A fault in plain words.
Our own Model 3 flagged its passenger seat sensor - the car only gave a code. kWhKey said what it means, who should sit where until it's fixed, and wrote the service request. Only the VIN and mileage are covered.
Know what woke your car.
Every wake-up, what caused it and for how long. On one of our cars it found Cabin Overheat Protection waking it all afternoon - and offers the fix.
Charging at a glance.
Live kW, time to your limit, what it added, and one tap to stop. Off-peak window and electricity cost, right below.
See every key to your car.
Shared drivers, every key on the car, and other apps that check in. Anything that needs a look shows in orange.
Security, simply.
Unlock alerts, the command log, devices and Bluetooth keys - one list.
See what you save.
Your driving against a gas car at local gas prices - as an MPG you can compare, and what you saved this week.
Your car crew, in one place.
Add the friends who drive electric and see everyone's cars side by side, each in its owner's own photo. See who got the new software first, whose car runs the most efficiently, and who's out driving or charging right now.
Your photo travels with your car: the shot you took is the one your friends see.
You choose what else they see. Where your car is, and its controls, are never shared.
Your cars, as your friends see them
Hold to unlock.
The Wear OS app is a Bluetooth key with no phone needed, and shows charge, range and every control. On a Galaxy Watch8 Classic the first version drained the battery - now it redraws only when something changed.
Everything it does
- A Bluetooth key. Standing next to the car, your phone and your watch lock it, unlock it and let you drive, with no
internet.
Why it exists
A parking garage has no signal, and a key that needs the internet fails exactly there. kWhKey talks to the car directly over Bluetooth, the way Tesla's own phone key does. - Controls from anywhere. Lock, climate, seat heat, charging, trunk and Sentry, through kWhKey's own server.
How it stays fast
The car streams its state to kWhKey, so the app opens on what the car just said instead of waiting to ask it - and it wakes a sleeping car only when you, or a routine you set, ask it to. - Charging and trips. Charge limit and current, your drives with distance and energy, battery health from your real
charging sessions, and a mileage log for taxes.
Built from real use
The mileage log came from needing a business-trip record that holds up: start, end, distance and purpose, exported as a report. - On your wrist. The watch app unlocks with a hold and runs climate and charging. It is included.
The battery lesson
The watch wakes and redraws only when something changed - and on Wear OS 6 or newer the app adds a kWhKey watch face that can show your two cars, switching each time the screen turns off. - Your car, your photo. Take a picture of your own car: kWhKey cuts the car out and puts it on its card,
the car's page and your watch - your color, your wheels.
How it works
The app shows where to stand and frames the shot; kWhKey cuts the car out and cleans it up, before and after side by side. The saved picture keeps only pixels - never the place or time written inside the photo file. A photo you put behind the car stays on your phone. - Friends. Add your EV friends and see everyone's cars side by side, each in its owner's own photo - who
got the update first, whose car runs most efficiently, who's out driving.
What friends can see
Always the car's picture, model, year and paint. Only if you switch it on: miles, range when full, time on FSD, efficiency, software version, what it's doing. Never where it is, its charge, or any control - and you can end a friendship any time. - For the whole household. Share your cars by invite. One subscription pays for a car on every phone and watch
of the household.
Who can do what
Owners add cars and people; members use the cars they were given. Every command is in the household's activity log, with who sent it and from which device. - Alerts in plain words. A door left open, a tire losing air, a charge that stopped - told once, in a sentence.
Tested against real readings
The tire check was replayed against our cars' own pressure history. A 5 psi loss on the first drive after a fill was caught in only 249 of 452 replays - so it was rebuilt to judge against the moment you said the tires were filled. Today it catches it. - Weather alerts. A tornado, a flash flood, extreme heat or a fire-weather day where your car is parked -
kWhKey passes on the National Weather Service's warning, with what to do.
How it works
Every 15 minutes kWhKey asks the National Weather Service which severe warnings are in force near each car - with only a rough position, about 11 km - and tells your household once per warning, naming the cars under it. Extreme warnings always come through. Switch it off under Notifications, and the weather service isn't asked at all. - Fixed the day we hit it. When a door reads open but is shut, tap Wake: kWhKey asks the car itself and corrects it.
October 17, 2026
While our Model Y was charging, the app and the watch both said the passenger door was open. The car's "closed" message had been lost on the way. That evening, Wake learned to re-ask the car.
Where it comes from
kWhKey is built and used every day on its makers' own cars - a 2020 Model 3 and a 2023 Model Y - in Los Angeles. Every feature above started as something we needed, and every fix as something that went wrong for us first.
- Used daily. Each change runs on our own phones, watches and cars before it ships.
- Tested hard. 1,248 automated tests for the phone and watch apps, 97 server test suites, and tests that hold this site's privacy and terms pages to what the code really does.
- Private by design. No ads, no analytics code, no data sold. The site you are reading loads nothing from anywhere else.
- Still growing. kWhKey is an ecosystem - phone, watch, server - and we keep improving it from what owners tell us.
What it costs
Or pay once: $199.99 per car for lifetime access, for as long as kWhKey provides its service for that car.
Every feature, for everyone. The watch app is included. No ads, ever. There is no free trial, no free version and no yearly plan. What it buys, and how to cancel
Where to get it
kWhKey is sold on Google Play, for Android phones and Wear OS watches - and nowhere else. kWhKey is sold in the United States only for now.
You need a Tesla and the Tesla account that owns it. One household can subscribe for up to 20 cars. Watches: Wear OS, such as Galaxy Watch4 or newer and Pixel Watch.
Good to know
Designed and built in Los Angeles, California. Your car's data is kept on U.S. servers, it is not sold, and there are no ads. What kWhKey keeps, and who else sees it
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