How do I change the battery to my heart rate sensor?
To ensure normal operation and performance of the sensor, use only CR2025 battery.
Keep new and used batteries away from children.
You can change the heart rate sensor battery yourself. To change the battery, follow the instructions below.
1. Lever the battery cover open by using the clip on the strap.
2. Remove the old battery from the battery cover.
3. Insert the new battery CR2025 inside the cover with the positive (+) side downwards.
4. Make sure the red sealing ring is in place, clean and intact. If the sealing ring is damaged, replace it with a new one*.
5. Put the battery cover back in place. First align the ledge on the battery cover with the slot on the connector, hold the ledge in place with your finger and then press the other side of the battery cover back into place. You should hear a snap. Ensure that the battery cover is properly closed to keep the sealing ring in place and to maintain the sensor’s waterproofness.
Sensor pairing with a Polar or third-party device or app is required after a battery replacement if you are using a firmware version earlier than 3.3.1 for H10 and 1.2.1 for H9.
* Replacement sealing rings can be purchased at Polar Service Centers. Check out the Service Center locations from the Service page.
See also the instruction video.
If the battery drains quickly
You can check the average battery lifetime of your heart rate sensor from the sensor user manual at support.polar.com/uk-en. If the battery seems to drain quickly:
- Make sure you detach the connector from the strap after training and store them separately.
- Make sure the strap and the connector are clean and intact. Get familiar with the detailed care and maintenance instructions.
- If the battery appears to drain quickly, consider trying a battery from a different manufacturer, as battery quality can vary among different brands. We recommend using batteries from reputable brands, such as Panasonic and Maxell, as their operational quality has proven to be reliable with Polar heart rate sensors.
- By default, H10/H9 sends heart rate signal via Bluetooth, ANT+ and GymLink. Turn off unnecessary connections from the sensor settings in Polar Flow or Beat app to extend battery life.
How do I know that the battery of my heart rate sensor needs to be changed?
Your heart rate sensor battery may need replacing if your training device or app does not show heart rate reading or if the heart rate reading is abnormal or stays unchanged for a long time. Abnormal heart rate readings may also be due to some other reasons than drained battery. See Abnormal heart rate readings during the exercise for more information.
If you have paired your H10/H9 with the Polar Flow or Beat app, you can check the the battery level status of the sensor from the app. See How to check the battery level status of my heart rate sensor? for instructions.