Does it need an iPhone app?
No. HRM Battery connects directly from Apple Watch to compatible Bluetooth heart-rate straps.
HRM Battery
Apple Watch chest strap utility
Chest strap battery, on your wrist
Find out whether your Polar, Garmin or Wahoo strap will survive the session — from Apple Watch, before you start, without an iPhone.
watchOS
BLE heart-rate straps
Battery percentage
No ads
Which straps report a battery level
Not every strap tells anyone how much battery is left. Where the number comes from depends on the brand, and that decides what you can see on your wrist.
| Strap | Where the battery number comes from |
|---|---|
| Polar H10, H9, OH1, Verity Sense | Polar's own measurement service reports a percentage, which the app reads directly. |
| Garmin HRM-Pro and HRM-Pro Plus | Garmin exposes battery through a vendor characteristic. The app only reads it once the strap identifies itself as a Garmin device. |
| Wahoo TICKR | Standard Bluetooth Battery Service. |
| Other Bluetooth LE straps | Anything that publishes the standard Battery Service works, including Coospo, Magene, Decathlon and similar. |
| Straps that publish nothing | Some straps only broadcast heart rate. No app can show a battery level that the strap never sends — you will see live BPM and no percentage. |
If your strap is missing here and does report a level, email the model and it gets added. If it shows BPM but no percentage, that is the strap's firmware, not a bug in the app.
One screen, before you start
Open it on the watch, connect, read the percentage next to live BPM. There is no iPhone app to open first and no account to make.
- The last strap is remembered for a one-tap reconnect.
- Live heart rate confirms the strap is awake and broadcasting.
- No data collection, no analytics, no ads, no tracking.
FAQ
Does it need a Polar or Garmin app?
No. HRM Battery reads the battery level straight from the strap over Bluetooth, so no vendor app or account is involved.
Why does heart rate show but not battery?
A strap can expose live BPM through the Heart Rate Service without exposing battery percentage through the standard Battery Service.
Does it collect training data?
No. HRM Battery has no account, no data collection, no analytics, no ads, and no tracking.
Support
For strap compatibility reports, connection trouble, or product questions, email support with your strap model and watchOS version.
Battery guide
How to check compatible chest strap battery levels from Apple Watch.
Email support
dan.urbanek.dev@gmail.com
Privacy policy
How HRM Battery describes data handling and permissions.
App Store
Download HRM Battery for Apple Watch.