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Changing Heart Rate Sensor Battery

To change the battery of the heart rate sensor yourself, carefully follow the instructions below:

When changing the battery, make sure the sealing ring is not damaged, in which case you should replace it with a new one. You can purchase the sealing ring/battery kits at well-equipped Polar retailers and authorized Polar Services. In the USA and Canada, the additional sealing rings are available at authorized Polar Service Centers. In the USA the sealing ring/battery kits are also available at

When handling a new, fully charged battery, avoid clasp-like contact, i.e. simultaneously from both sides, with metal or electrically conducting tools, like tweezers. This may short circuit the battery, causing it to discharge more rapidly. Typically, short circuiting does not damage the battery, but it may decrease the capacity and the lifetime of the battery.


  1. Using a coin, open the battery cover by turning it counterclockwise to OPEN.
  2. Insert the battery (CR 2025) inside the cover with the positive (+) side against the cover. Make sure the sealing ring is in the groove to ensure water resistance.
  3. Press the cover back into the connector.
  4. Use the coin to turn the cover clockwise to CLOSE.


  1. Lever the battery cover open by using a small flat-headed tool.
  2. Remove the old battery from the battery cover.
  3. Insert the new battery (CR2025) inside the cover with the negative (-) side outwards.
  4. Align the ledge on the battery cover with the slot on the connector and press the battery cover back into place. You should hear a snap.

Danger of explosion if the battery is replaced with wrong type.