The Battery Bandit: Polar H9’s Unexpected Drain Dilemma!

Good morning everyone (UK time)

I possess a Polar H9 that is approximately 2 years old.

I usually change the strap annually & clean them weekly (I have a new strap set for 2025)

In the past, the device has typically consumed about one battery per year (Energizer Lithium CR2025)

Just prior to Christmas, the device began indicating low HR readings while connected to TR/Zwift via ANT+. I have encountered this previously when the battery is running low, so I replaced the battery and everything was resolved. Fast forward to 2 weeks later (New Year) and it’s doing it again. I considered it might be a previously low battery (that I removed from a blister pack, hence it’s new), so I tried another one, and once more, the issue was resolved.

I got on the bike last night and this time, the device connects to Zwift (ANT+) but shows a HR of zero. I opened TR & connected using BTE, however, the connection wouldn’t stay active for more than a second or so before disconnecting. I installed the Polar Beat app to check the status and while it could detect the monitor, it failed to establish a connection through BTE.

I inserted another fresh battery & yet again, it functioned flawlessly.

The device is always dried and disconnected from the strap when not in use.

All I can ponder is whether the device is now defective & is rapidly depleting batteries unnecessarily, or if the pack of batteries is faulty (The pack claims a shelf life of 10 years and was purchased last year).

For the time being, I’ve kept the previously depleted battery, the one that failed last night & the new one. I’ve also removed the battery from the device until I can perform voltage tests with a meter on all three batteries to check if they are coming from the pack already drained.

Has anyone else encountered similar with the H9 & did they discover a solution?

Thanks

You appear to be taking all the correct steps

Perhaps consider attempting a reset?

When it wouldn’t connect to the Polar Beat app while being visible, I attempted to remove the battery and hold the two metal contacts with my fingers for ten seconds last night. I believe this is standard procedure for resetting by Polar, however, afterwards, it persisted to show available but wouldn’t connect properly.

The new battery seemed to solve the issue.

Are you utilizing the same brand of battery?

All have been Energizer Lithium CR2025 from the identical blister pack of 4.

I can’t recall the brand of battery that originally came with the HR monitor & was used in the first year

It might be beneficial to get in touch with Polar Support regarding this problem if you haven’t done so already – they should be able to assist or potentially provide a replacement HR monitor if required!

My Polar H10 appears to experience cycles of rapidly depleting batteries. All I can speculate is that it may be attempting to remain connected to something, even though I detach it after each use?

Interestingly, I noticed mine performed better if the detached pod was kept with studs facing up rather than down

Can’t say I’ve been mindful of the orientation when it’s not in use, but anything is worth trying