Cellmate privacy policy

Effective 2 November 2026. Applies to the Cellmate Android app (dev.garageai.cellmate), published on Google Play by Garage AI, and to the Cellmate web app at cellmate.reiners.io.

In short

Cellmate collects nothing. It reads your batteries over Bluetooth and keeps everything it learns on your device. It has no ads, no analytics, no accounts, and it never sends your data to us or to anyone else.

What Cellmate stores, on your device only

• The batteries you add: their Bluetooth address, the serial or name they report, and the nickname, rated capacity and pack groupings you give them.
• Readings from those batteries (voltages, current, temperatures, state of charge and similar) and the history, event log and charts built from them.
• Your settings and alert thresholds.

This lives in the app's private storage. Uninstalling the app deletes it. On Android it may be included in your own Google device backup if you have that turned on; that backup is handled by Google under your account, not by us. A configuration export is only made when you ask for one, and goes where you choose to save or share it.

Bluetooth and permissions

• Nearby devices (Bluetooth scan and connect): to find and talk to your battery management systems. Cellmate declares that it does not use Bluetooth scans to work out your location, and it does not ask for location on Android 12 or newer. (Android 11 and older require the location permission for any Bluetooth scan; Cellmate uses it only for that.)
• Notifications: for battery alerts, charge-complete notices and the ongoing monitoring notice.
• Foreground service, wake lock and battery-optimisation exemption: so monitoring and alerts keep working while your phone is asleep.

What Cellmate collects

Nothing. There is no sign-in, no ads, no analytics or crash-reporting service and no server of ours that the app talks to. We do not receive your name, email address, location, device identifiers, battery data or anything you do in the app.

When you install or buy the app, Google Play handles the download and the payment under Google's own privacy policy. We do not get your payment details from it.

Children

Cellmate is a tool for battery owners and is not directed at children. It collects no personal information from anyone, children included.

Changes

If a future version ever changes any of this, this page will say so before that version is released, with a new date at the top.

Contact

Questions about this policy or the app: justin@reiners.io.

Cellmate is an independent app. It is not affiliated with or endorsed by any battery or BMS maker.