How do I change the battery?

this is f11 it may help you
http://timlaqua.com/2008/09/how-to-replace-the-battery-in-a-polar-f11-heart-rate-monitor-hrm/

There are two types of straps for Polar:

1) hard rubber/ solid - These can not have the battery changed.

2) soft strap with connector in middle - these you can change the battery.

If you have the soft strap, it will have a small hard around 3 inch long block that "snaps" onto the strap to connect it. These have a battery compartment. Turn it around and you will see the outline for the battery compartment. These are not always easy to open, and the batteries are a little harder to find. Take it into any watch repair and they should be able to pop a new battery in for you pretty easy.

There is a link on my tips and tricks page to get manuals for Polar products, the T-31 wearlink is the product we are talking about, it has the how to change the battery and battery type.

The Polar watches are not designed to be taken apart. It is a common misconception to think of them as watches and not mini computers.

The best case scenario is too send your watch and clip into a Polar Authorized Service center. Polar headquarters are in Finland and their should be a close center for you in Oslo.

Visit www.polar.fi to find your local service center.

Another thing, when you change the battery yourself the watch loses it's seal and is not watertight anymore. Polar uses a special vaccum chamber to repressurize the seal to maintain watertightness.

The only solution is too send into a Polar Authorized Service Center. Regular watch shops are not equipped to diagnose and/ or fix problems with Polar watches, or most other Heart Rate watches for that matter.

This happened to me, I think it happens when theres not enough contact with skin and monitor, I put more water onto my skin and the heart rate monitor and it sorted th eproblem

Always look at the numbers on the old battery first and replace with the same. If you don't have the old battery then I would check with a local business that sells that watch. Sometimes you might find the battery number engraved on the case back. Hope this helps you,.good luck.

I had the same problem and found that the chest strap wasn't tight enough to get a good reading. If that doesn't work, you might have to send it in to have the battery changed. Search for a Polar authorized service center. It gives you some troubleshooting tips too. Good luck.

Follow this link:

http://www.polar.fi/en/support/product_support?product=125

This is original Polar support site.Here you will find all the info available.

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Make sure you don't have the battery in upside down. The large outside case of a button cell is the +positive side.

try a new battery