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935 and External HRM Problem

I've been using the FR935 with external heart rate monitors for over 3 years. I use the Polar H10 and the HRM-Dual. In the past, I've successfully used both in ANT+ and BT. I prefer the strap on the H10, but I like the battery life of the HRM-Dual. Previously, the only time I had issues with either of the monitor was if the battery was going low or the strap needs replacing. I run or ride about 6 days a week, so I change the straps about once a year.

Recently, over the past couple months, I've been having an issue that I just can't figure out. Both of the straps are relatively new and they both test very low resistance with my multimeter.

The issue is that WHEN RUNNING ONLY the HR on the H10 will start to falsely read around the hour mark. It will slowly fall from 130bpm down to 90bpm, even though I'm running at the same intensity. The HRM-Dual also acts up at around 1 hour into the run. However, The Dual may go way high(170bpm) or way low(90bpm). The weird thing is that I've had ZERO PROBLEMS WHEN USING EITHER UNITS WITH MY BIKE.The following are the actions I've tried:

- Clean the strap with soap ad water.

- Clean the unit with soap and water.

- Clean the contacts on the strap and the unit with an electronic control cleaner

- use the Garmin unit with the Polar strap and visa versa

- Use various shirt materials.

- rotate the strap around my body, both closer and further away from the watch.

- Ensure the watch is completely charged.

I seemed to have some success with cleaning the contacts and making sure the watch is fully charged, but today the HRM-DUAL went crazy during my run and it was fully charged and I meticulously cleaned the contacts on the strap and unit.

The only thing I could think of is that there is something wrong with wireless system on the watch or that the watch can't hold the minimum required voltage to ensure a solid connection. The issue with this theory is that I have zero problems when using either strap with my bike.

The watch really has had no major bangs or drops. The battery life on the watch isn't what it once was, but it's still multiple days.

Anyways, any ideas are welcome.

Wes

0 mamat.54 over 3 years ago

Same issue here. Want to report this occurs over either ANT+ or BT.

0 waslin over 3 years ago in reply to mamat.54

Actually, I've had success in resolving the problem. It seems that the interface between the control unit and the strap is the issue. I'm not sure in the snaps get tarnished over time or worn down over time, but when I improved the conductivity between the snap interface the problem disappeared.

I used an electronic control cleaner to resolve the issue. Just before I go out, I clean the contacts on both the brain and the strap with a Q-tip covered in cleaner. I MAKE SURE I IMMEDIATELY WIPE OFF ANY EXCESS CLEANER AND THROUGHLY WASH MY HANDS BEFORE I GO RUNNING. THIS ENSURES THAT NO CLEANER CAN GET WIPED INTO MY EYES DURING THE RUN. THIS IS VERY IMPORTANT NOT TO FORGET. Since doing this, I've had zero issues.

0 waslin over 3 years ago

UPDATE:

I just thought I'd share an update on this issue in case anybody else encounters this issue. I've completed 12 runs since my last post without a single problem. Eight of these were with the Polar H10 HRM and four of these with my Garmin HRM-Dual. In this period, before each run, I filled the snaps on the strap with a little Spectro 360 Electrode Gel, before snapping on the controller. This stuff is water soluble so it just washes off after the run.

There hasn't been so much as a blip since using the electrode gel. My guess is that the bouncing during running is somehow disrupting the contact at the snap. I suspect that maybe the tension lessens as the strap is used over and over. Maybe this issue is specific to me, but I'm betting there are others out there that are having a similar issue.

Good Luck.