Privacy Policy
Battery Sink shows the battery level of your devices on your other devices. To do that, each device sends its battery reading to the Battery Sink server, and your other devices read it back. This policy explains exactly what is sent, how long it is kept, and how to delete it.
The short version: Battery Sink has no sign-up, no email address, no ads, no analytics, and no tracking. It stores only the latest reading from each device, and lets you delete everything from the app at any time.
What we collect
When a device running Battery Sink syncs, it sends the following to our server:
| Data | Why | How long it is kept |
|---|---|---|
| Your account code (a 12-digit code the server creates when you make an account). The server stores only a one-way SHA-256 fingerprint of it, never the code itself. | Groups your devices together so only devices that know the code can join them. | Until you delete your account. |
| An account token for each device, a random secret given to the device when it joins your account. The device keeps it in its Keychain; the server stores only a one-way fingerprint of it. | Proves each sync comes from a device you added. | Until you delete your account. |
| A random device identifier the app generates on install. It is not your Apple ID, serial number or advertising identifier. | Tells your devices apart. | Removed 72 hours after the device last reports, or when you remove the device or delete your account. |
| The name of each device and accessory, for example the name you type in Settings, your Mac's computer name, or the name a Bluetooth accessory advertises. | Shows which device each reading belongs to. | Same as above. |
| Device type (iPhone, iPad, Mac, Watch, keyboard, headphones or other), battery percentage, whether it is charging, and when the reading arrived. | Shows the current battery on your other devices and widgets. | Same as above. |
| Custom icons you choose for devices. | Shows the same icon on all your devices. | Until you change it, remove it, or delete your account. |
Battery Sink does not collect your name, email, phone number, contacts, location, photos, health data, Apple ID, advertising identifier, or any usage analytics or crash reports.
Bluetooth
On iPhone, iPad and Mac, Battery Sink asks for Bluetooth permission so it can read the battery level that connected accessories (such as keyboards, mice and game controllers) publish. It reads only the accessory's name and battery level, and sends them to the server as described above. It does not scan for or record other nearby devices.
Data that stays on your device
Your account code, your device's account token and connection details are kept in your device's Keychain. Your device list order, hidden devices, low-battery alert settings and the last downloaded readings are kept on the device in the app's own storage so the app and widgets work offline. Low-battery alerts are local notifications created on your device. The Apple Watch app gets its readings from your iPhone over Apple's Watch connection.
Where your data is stored
The Battery Sink server runs on Cloudflare (Cloudflare Workers and Cloudflare D1). Cloudflare processes this data on our behalf as our hosting provider. All traffic between the app and the server is encrypted with HTTPS. Data may be stored or processed in any country where Cloudflare operates.
To protect accounts from code guessing, the server limits how many requests can come from one network address per minute. Cloudflare uses your IP address briefly for this limit. Battery Sink does not store IP addresses and does not log request contents.
Who can see your data
Anyone with your account code can see the devices on your account, so share it only with devices and people you trust. We do not sell, rent or share your data with anyone, and we do not use it for advertising. We may disclose data only if required by law.
Tracking
Battery Sink does not track you across apps or websites, does not use third-party analytics or advertising SDKs, and does not combine your data with data from other companies.
Deleting your data
- Delete everything: open Battery Sink, go to Settings, and choose Delete Account. This immediately removes all devices and icons for your account from the server.
- Remove one device: tap the trash icon next to it. Its reading is removed from the server.
- Automatic deletion: a device that stops reporting is removed after 72 hours. Each new reading replaces the previous one; no history is kept.
- Deleting the app removes the data stored on that device. Your account code may stay in the iPhone Keychain so you can reconnect later; delete your account first if you want it gone everywhere.
Children
Battery Sink is a general-audience utility. It does not knowingly collect personal information from children, and it collects no personal contact information from anyone.
Changes
If this policy changes, we will update this page and the effective date above. If a change affects what data is collected, we will mention it in the app's release notes.
Contact
Questions or deletion requests: battery@v-estia.com.