Heart rate monitors

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Carl Watts
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Re: Heart rate monitors

Post by Carl Watts » June 19th, 2024, 5:29 am

I don't recommend putting the straps in the washing machine. basically the strap fails when the carbon electrodes change resistance with just a combination of chemicals and just age, the resistance increases over time and the strap stops working.

If you own a multimeter then you can check the strap, at about 10mm apart put the probes on the strap carbon an new strap will be like 150 Ohms, as they age it eventually goes thousands of Ohms and the strap starts getting intermittent during operation or will not turn on.

I have to at least wash mine in plain water twice each time I wear it because if not after a week or two it just stinks of stale sweat. Washing it before you wear it soaks the strap with plain water instead of it ending up soaking up pure sweat.
Carl Watts.
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gvcormac
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Re: Heart rate monitors

Post by gvcormac » June 19th, 2024, 8:44 am

Carl Watts wrote:
June 19th, 2024, 5:29 am

If you own a multimeter then you can check the strap, at about 10mm apart put the probes on the strap carbon an new strap will be like 150 Ohms, as they age it eventually goes thousands of Ohms and the strap starts getting intermittent during operation or will not turn on.

I have to at least wash mine in plain water twice each time I wear it because if not after a week or two it just stinks of stale sweat. Washing it before you wear it soaks the strap with plain water instead of it ending up soaking up pure sweat.
1. I don't follow your resistance measurment technique. Can you provide a picture?

2. Do you keep your strap in a gym bag or something? I wipe and hang dry mine. It doesn't stink. I do recall that when I used T30/T34 which does not unsnap, I had to clip it to the outside of my gym bag or it would never shut off ... so I never really did the stink test.

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Re: Heart rate monitors

Post by Annisotropic » June 19th, 2024, 11:32 am

Since we're talking about Polar, I have two old chest straps in the house, around 15 years old. - each consists of a fairly stiff piece of black plastic, with a kind of buttonhole at each end for the elastic part.
I've just assumed that they are museum pieces, beyond any redemption - but I hate to throw anything away if it has any conceivable value.

Is it time to say goodbye to them? 😢😢😢

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Re: Heart rate monitors

Post by gvcormac » June 19th, 2024, 1:45 pm

Annisotropic wrote:
June 19th, 2024, 11:32 am
Since we're talking about Polar, I have two old chest straps in the house, around 15 years old. - each consists of a fairly stiff piece of black plastic, with a kind of buttonhole at each end for the elastic part.
I've just assumed that they are museum pieces, beyond any redemption - but I hate to throw anything away if it has any conceivable value.

Is it time to say goodbye to them? 😢😢😢
I'm keeping mine because they talk to my treadmill and my elliptical, which only speak the old 5khz "gymlink" protocol. The H9/H10 is the only modern HRM that purports to speak Gymlink, but the old straps are much more reliable.

Unfortunatly the plastic gets brittle and several of mine have snapped, rendering them practically unusable.

Also, the batteries are not easily replaceable. But it is possible to do a surgical replacement with a scalpel. The one I did was a standard 2032 battery, and I put on a plastic patch with silicon seal to cover the wound. My memory fades, but I may had had to solder a wire onto the battery. Or maybe there was a clip ...

I also have an FT1 wrist receiver that I replaced the battery on. Unfortunately it has a non-standard wrist strap and the one that's on it is failing. I've patch that, too.

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Carl Watts
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Re: Heart rate monitors

Post by Carl Watts » June 19th, 2024, 9:28 pm

Annisotropic wrote:
June 19th, 2024, 11:32 am
Since we're talking about Polar, I have two old chest straps in the house, around 15 years old. - each consists of a fairly stiff piece of black plastic, with a kind of buttonhole at each end for the elastic part.
I've just assumed that they are museum pieces, beyond any redemption - but I hate to throw anything away if it has any conceivable value.

Is it time to say goodbye to them? 😢😢😢
Probably dead, those ones had a large sealed Lithium battery in them and 10 years is the battery life.

They have moved to replaceable batteries now but they probably don't last 10 years anyway. The CR2032 was the wrong battery size to use they should have gone CR2450 but it would have resulted in a larger module. Getting the average user to change the battery every year doesn't work.
Carl Watts.
Age:56 Weight: 108kg Height:183cm
Concept 2 Monitor Service Technician & indoor rower.
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Carl Watts
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Re: Heart rate monitors

Post by Carl Watts » June 19th, 2024, 9:34 pm

gvcormac wrote:
June 19th, 2024, 8:44 am


1. I don't follow your resistance measurment technique. Can you provide a picture?

2. Do you keep your strap in a gym bag or something? I wipe and hang dry mine. It doesn't stink. I do recall that when I used T30/T34 which does not unsnap, I had to clip it to the outside of my gym bag or it would never shut off ... so I never really did the stink test.
1. Pretty simple poke the probes into the carbon strap at various points keeping the tips 10mm apart.

2. If your strap doesn't stink after 2 weeks without washing it your not training hard enough. Sweat stinks I can only use my bike outfit twice tops and then it stinks because its been saturated in sweat. The strap is rinsed and dried with a towel and hung on the bike to dry. You want to minimise the time it spends wet or it will not turn off reducing the battery life. They turn on an off by sensing the resistance between the electrodes and water is a near short circuit.
Carl Watts.
Age:56 Weight: 108kg Height:183cm
Concept 2 Monitor Service Technician & indoor rower.
http://log.concept2.com/profile/863525/log

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Re: Heart rate monitors

Post by Annisotropic » June 20th, 2024, 6:37 am

Found an email address for polaruk; all reviews say that customer service is appalling but hey-ho, I've got nothing to lose. Assuming that I draw a big fat silence from them, I'll have a go at replacing the battery - plenty of instructions on various forums of how to do it with a Stanley knife and duct tape, I have two (T-61 coded) so I get two chances to get it right/mess it up.

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Re: Heart rate monitors

Post by gvcormac » June 20th, 2024, 12:16 pm

Annisotropic wrote:
June 20th, 2024, 6:37 am
Found an email address for polaruk; all reviews say that customer service is appalling but hey-ho, I've got nothing to lose. Assuming that I draw a big fat silence from them, I'll have a go at replacing the battery - plenty of instructions on various forums of how to do it with a Stanley knife and duct tape, I have two (T-61 coded) so I get two chances to get it right/mess it up.
When I did a battery replacement, YouTube didn't exist. I'm not even sure the Web existed. Not sure what the Polar model was, but it was like a T31, only with a fixed-width strap.

I cut a hole in the front, which, based on the YouTube videos I've seen, would still work, but is perhaps not the optimal method. When I did that, the clip(s) from the outside of the battery fell out, and that's probably what I soldered.

It appears to me that the best approach is to get the back plastic off (either with heat or just by cutting/peeling the glue). Then take the front cap off, and undo the screws from the back. This avoids prying the circuit board out from the back, which you'll see in a number of videos. Put it all back together and seal the seam with silicon seal.

I just counted -- I have five T31/T34, two with intact straps, two with broken connector holes (which could maybe be patched/repaired) and one snapped between the sensor and the electrode. If I decide to do this again I can practice on the snapped one, I guess. For now, I still have a working T34 (uncoded) and a working T31 (coded) so I'm not in a rush.

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Re: Heart rate monitors

Post by gvcormac » June 20th, 2024, 2:11 pm

Here's a cheap Gymlink strap on Ali Express: https://www.aliexpress.com/item/32830159930.html

Not as much fun as replacing the battery in a T31/34 but probably the "sensible" choice.

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Re: Heart rate monitors

Post by carldstevens » June 25th, 2024, 7:06 am

I've had success with MyZone chest HRM. It readily connects to the row and ski.

Catl in Dover

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Re: Heart rate monitors

Post by Annisotropic » July 2nd, 2024, 7:19 am

Just a quick update on the HW9 Coospo armband - bought from Aliexpress for £13, it arrived (UK) in under a week, it works well and stays in place. The PM5 detects it easily, although occasionally loses the connection.
The only issue I have is with my low resting HR (not exceptionally fit, nor on any medication, it's just a quirk). The HW9 allows customization with a personal MHR, but not a resting HR, so the calculated zones are very inaccurate. The actual numbers seem to be accurate, as displayed on the PM5 or phone, but I don't get any benefit from the coloured LEDs. If I'd known this, I'd have bought a cheaper model.

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Re: Heart rate monitors

Post by WayHand » July 15th, 2024, 2:31 pm

Another way to test if your strap has gone bad is to examine the HRV data in an app. I transmit all my HR data to Garmin Connect and from there to Runalyse. Runalyse shows a ‘Valid’ percentage for the HRV data. If it is high then the strap is OK, say >90% but if it is low, say <10%, then the strap is suspect. However, just noted the price of the strap from Aliexpress, makes them very disposable!
Wayne Handley
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gvcormac
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Re: Heart rate monitors

Post by gvcormac » July 15th, 2024, 5:34 pm

I really don't understand this "strap gone bad" thing. I've owned at least a dozen chest HRMs, mostly Polar, and never encountered this problem before the Polar H9s.

I did recently play with my H9 with Elite HRV. It reported some glitches, but I have no idea what's normal. I decided I don't have the time to bother with daily HRV readings, so I didn't try my other chest HRMs.

In other applications, my Garmin Dual seems to be the best, and Coospo 808S pretty good. H9 worse. I know this is contrary to accepted wisdom, but Polar doesn't do it for me any more.

On a related note, my $CA 25.00 5khz Ali Express chest strap works fine on my legacy equipment -- better than the H9 and at least as well as my nearly dead T31s and T34s.

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Carl Watts
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Re: Heart rate monitors

Post by Carl Watts » July 16th, 2024, 12:09 am

gvcormac wrote:
July 15th, 2024, 5:34 pm
I really don't understand this "strap gone bad" thing. I've owned at least a dozen chest HRMs, mostly Polar, and never encountered this problem before the Polar H9s.

Well thats quite funny really, I have owned a least a dozen but they don't go bad.

I use mine 4 times a week and have probably gone through a couple of the old Garmin HRM1 because the battery cover lugs break off, water gets in and then its toast. I have had a couple of straps fail like I said they get old and the resistance changes, you cannot change that but the replacement straps for the likes of the Garmin dual are as cheap as on AliExpress now anyway.

Probably the best run I have had now is from the Garmin RUN. never actually had the transmitter fail so got two of the older Garmin ANT+ only in the draw as spares now when I discovered the cheap straps.
Carl Watts.
Age:56 Weight: 108kg Height:183cm
Concept 2 Monitor Service Technician & indoor rower.
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dabatey
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Re: Heart rate monitors

Post by dabatey » July 16th, 2024, 1:51 pm

I've had my H10 for 3 years now and the strap has only been washed once after it was getting a bit dry and crusty. Probably been used 4 or 5 times a week. Never failed to connect, I give it a quick lick before putting on and it's straight in. Only time it has failed me is when it has needed the battery changing and good as gold with a new battery.
Age 50....Weight 61 Kg....
Row Aug 21 to Mar 22. Cycle Mar 22 to Jun 23. Now mixing the 2.
2K 8.33 (19 Sep 21)...7.37.0(15 Mar 22)
5K 22.14 (2 Oct 21)
Resting HR 45 (was 48 in 2021)....Max HR (Seen) 182 [185 cycling]

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