Your car at a glance
Charge level, range, health and efficiency on one live gauge, plus a short daily brief of yesterday's drives, charges and cost.
390Range km
93Health %
161Wh/km
Premium EV analytics
Drag the stone to spin it. Choose your own gem in the app.
Know your battery. Really.
The analytics app for Tesla owners. Gemwatt turns your car's data into calm, clear insight: battery health, real efficiency, every trip, and what charging truly costs.
Battery
78%
Parked · updated 3 min ago
Coming soon to iOS and Android.
Made for Tesla owners. Connects through Tesla's official Fleet API. Independent; not affiliated with Tesla, Inc.
What it does
Everything your car knows, made clear.
Five calm screens. No dashboards full of noise, just the numbers that matter and what they mean.
See exactly how every charge went
Charging speed over time, energy added, and the real cost, with separate prices for home and public charging.
189kW peak · DC
Fast at first, then tapers as the battery fills.
Illustration with example numbers.
Efficiency, trip by trip
Consumption per km (or mile) over time, and how your speed changes it, so you can see your sweet spot.
Switch between kilometres and miles any time.
Estimated battery health
An estimate of your usable capacity over time, built from your real charging sessions. It is an estimate, not a lab measurement.
What driving really costs
Cost per month, per km, and per charge, using the prices you set.
Your route, coloured by speed
Open any trip to see where it went. The map is optional: location is only used if you allow it.
Illustration with a sample route.
Everything connected
One car. One calm view of everything.
Data flows in from your car through the official API, Gemwatt turns it into insight, and the results land in the app.
- Data inYour car's readings arrive through the official API.
- Battery healthEstimated capacity over time.
- Smart alertsA heads-up when something is worth knowing.
- Cost & chartsWhat each charge and kilometre really costs.
Who it's for
Built for people who love driving electric.
Whether you commute daily, chase long road trips, or keep a car for a decade, Gemwatt answers the questions the car's own screen does not.
Daily drivers
What does each kilometre really cost you? See efficiency by trip and by speed, in kilometres or miles.
Road trippers
Compare how a home charge and a fast charge actually behave: speed over time, energy added and price.
Long-term owners
Track your estimated battery health over the years and spot changes early.
How it works
Connect once. Understand always.
Connect securely
You sign in on the car maker's own official page and approve exactly what Gemwatt can see. We never see or store your password.
We learn your driving
Gemwatt turns raw readings into trips, charging sessions and a battery estimate, using as little data as it can.
You get clarity
Clear numbers, honest estimates and gentle insights, in a calm app that is a pleasure to open.
Privacy & control
Your data stays yours.
A car's data is personal. Gemwatt is built to collect only what it needs, and to let you leave whenever you like.
- Read-only. Gemwatt never sends commands to your car. It only reads data.
- No passwords. You sign in on the official page. Gemwatt receives a permission token, never your password.
- You choose the access. Location is optional and off unless you turn it on.
- No ads, no selling data. We do not sell your personal data.
- Leave any time. Disconnect, and delete your account and data from the app or by email.
Honest by design
Some figures, such as battery health, range and cost, are estimates calculated from available data. We label them clearly and never present an estimate as a measurement.
Gemwatt is for information. It is not a safety system, and it should never replace your own judgement while driving.
FAQ
Good questions.
What is Gemwatt?
An app that turns your electric car's data into clear insight about battery health, efficiency, trips and charging cost.
Which cars does it work with?
Gemwatt is made for Tesla vehicles and connects through Tesla's official Fleet API. Supported models and regions may change, and we will list them before launch.
Is it free?
Pricing is not final yet. We will publish it before launch. Gemwatt will not show ads.
Is my battery health exact?
No. It is an estimate based on your charging sessions. Real capacity can differ, and the estimate improves as more data arrives.
Can Gemwatt control my car?
No. Gemwatt is read-only: it shows and analyses your data, and it cannot lock, unlock, start charging, change the climate or wake the car.
Do you track my location?
Only if you choose a feature that needs it, such as the trip map. You can switch it off and ask us to delete it.
How do I delete my data?
Use the delete option in the app, or follow the steps on our data deletion page. You can also revoke access from your car maker's account at any time.