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How to replace the battery in a Polar F11 Heart Rate Monitor (HRM)

Disclaimer: The user manual for the Polar F11 clearly states to take the HRM to a Polar dealer and have them replace the battery - taking the back off could void your warranty. If you wish to be 100% sure that you maintain the water-resistant seal and do not want to void your warranty - or risk breaking your HRM (certainly a possibility when you take it apart...), take the unit to an authorized Polar dealer and have them replace the battery.

Step 1: Remove the back cover (4 little screws - make sure you have the right size screwdriver or you'll strip them out). Also note that the back has a water-resistant seal - keep this clean and remember that there is always a chance that the seal may be damaged if you do this yourself.
Step 2: Remove the internal unit from the watch casing (it just pulls out).
Step 3: Get something to pry the battery latch tab with (I used another small screwdriver)
Step 4: Take whatever you used to pry the latch tab out with and use it to pry the battery up by placing the device (screwdriver in my case) in the notch above the latch (see picture).
Step 5: Go to Wal-Mart and purchase a new CR2032 watch battery (you may want to do this before hand... I didn't know what battery it used so I had to take it out first) - runs about $3.50.
Step 6: Put the battery back in and put everything back together.