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Voltmeter is a native iPhone and Android app for TeslaMate, the self-hosted data logger for your car. It connects to the Grafana that ships with TeslaMate and shows your battery, drives, charging and TeslaMate's dashboards in a fast, phone-sized app, with no web views.

• A running TeslaMate installation, with its Grafana reachable from your phone.
• A Grafana service account token with the Viewer role.

No server yet? Tap Explore with demo data on the welcome screen to try every screen with a made-up car.

1. Open your TeslaMate Grafana in a browser and sign in as an admin.
2. Go to Administration → Users and access → Service accounts.
3. Choose Add service account, give it a name such as "Voltmeter" and set the role to Viewer.
4. Open the new account, choose Add service account token, then Generate token.
5. Copy the token (it starts with glsa_) and paste it into Voltmeter. Grafana only shows it once.

Viewer is enough: Voltmeter only reads data, it never changes anything in Grafana or TeslaMate.

The address you use to open TeslaMate's Grafana in a browser, including the port. For a default Docker install that is usually something like http://192.168.1.10:3000. If you reach Grafana through a reverse proxy, enter the full URL, including any path, for example https://example.com/grafana.

If you leave out http:// or https://, Voltmeter assumes http://.

• Check that your phone is on the same network as the server, or connected to your VPN.
• Open the same address in your phone's browser. If Grafana doesn't load there, Voltmeter can't reach it either.
• Make sure you included the port (for example :3000).
• On iPhone, check Settings → Privacy & Security → Local Network and make sure Voltmeter is allowed. On Android 17 and later, allow local network access when Voltmeter asks.

The token was mistyped, revoked, or has expired. Create a new token as described above and paste it again.

Voltmeter looks for the PostgreSQL datasource that TeslaMate installs in Grafana. Check that you are connecting to TeslaMate's Grafana (not another Grafana instance) and that its TeslaMate datasource still exists under Connections → Data sources.

Yes, as long as your phone can reach Grafana. The safest way is a VPN such as WireGuard or Tailscale, so Grafana never has to be exposed to the internet. If you do publish Grafana through a reverse proxy, use HTTPS.

TeslaMate usually runs on your home network. iOS and newer versions of Android require apps to ask before connecting to devices on your local network. Voltmeter uses it only to talk to the server you enter.

Voltmeter rebuilds TeslaMate's Grafana dashboards natively: Battery Health, Charge Level, Projected Range, Vampire Drain, Drive Stats, Efficiency, Mileage, Charging Stats, Statistics, States, Temperatures, Updates, Locations, Trip and Visited, plus a detailed view for every drive and charge. Pin your favourites to see a live value on the dashboards tab.

Voltmeter follows the units set in TeslaMate's own settings (km or miles, °C or °F). Change them in TeslaMate and pull to refresh.

Tap the car name at the top of the hub to switch between the cars in your TeslaMate.

A dash means TeslaMate has no data for that value yet, for example charging cost when you haven't set a price for a location in TeslaMate, or efficiency before TeslaMate has logged enough charges.

Go to More → Address. Choose Edit to change the server or token, or Disconnect to remove both from the device. The same place takes you out of demo mode.

Voltmeter talks to the server address you enter to read your car's data, and the app has no analytics or tracking of its own. Your API key is kept in the device's secure storage (the iOS Keychain, or encrypted with the Android Keystore).

Map backgrounds are OpenStreetMap tiles downloaded from OpenFreeMap. Your routes and positions are drawn on your phone and never sent to them. See the Privacy Policy for details.

No. Voltmeter is an independent app. It is not affiliated with, endorsed by or sponsored by Tesla, Inc. or the TeslaMate project.

Email Voltmeter support with your phone model, its OS version and what you see on screen. Please never send your API key.