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Hrm Pro and Run are unusable after first change of factory battery cause the sudden discharging of all new batteries

After that to ALL of mine straps owned, two Hrm Run and now a Hrm Pro, has happened the same thing, I'm sure of that: after changing factory battery the strap drains all brand new battery that you put in in a few hours or days or little more but there's nothing to do, it's like they were short circuited on the strap, when you wear the first time all seems working then the battery get discharged. I tried everything, even put the battery on reverse side for a while but there's nothing to do. I'm sure that Garmin is aware of this problem cause on the web there are many cases like mine, I also suppose it's done on purpose otherwise it's unesplicable how this happens and how they didn't fix it. You can change under warrenty the first time but at the end of two years you are forced to buy a new one since the factory battery lasts 1 year. For me this situation it's a shame since that this are very expensive devices, next time I think I'll buy a normal strap from another brand giving up to running dynamics and other features.

  • I received my HRM-PRO as a gift last Xmas. In June this year I had to replace the battery. So far, with mostly daily use, the new battery continues to work as expected.

    Are you sure your batteries are not duds? Are they genuine or fakes? What is the voltage when new? It should be 3.2V in my experience. 

  • I'm sure that is not a question of kind of battery, I put on batteries of the same exact type of the first battery, CR2032 as indicated on the Hrm, genuine brand new batteries from the best brands that works perfectly in other devices. That is what happened to me: first Hrm Run bought 11/2015, replaced battery 4/2017 then worked 2 months, replaced batteries again and didn't work anymore. Second Hrm Run bought 12/2017, replaced battery 6/2019 , this time worked until 12/2020, then replaced battery again and since that didn't work, new batteries always sudden discharged. Third strap Hrm Pro bought 1/2021, replaced battery 8/2021, tried 5 new battery always discharged in a day. So if you're lucky they can last again after replacement some months, anyway generally they goes broken very fast. I found people on web who happened the same thing. They are disposable heart rate monitors that's the fact.

  • if the HRM-Pro and HRM-Run use the same O-ring design as the HRM-Tri, that is why

    the factory o-ring immediately starts to deform and fail to seal after the first battery change in the HRM-Tri so tiny amounts of moisture get into the electronics and that is the end of that, it causes a non-stop low level short circuit or constant battery drain

    there are threads around here trying to find an exact O-ring replacement size but little or no success

    someone who knows what they are doing needs to carefully measure both the INNER diameter and OUTER diameter and thickness of the factory O-ring and we can search again

    garmin is useless and will not supply replacement O-rings

    it needs to be changed with EVERY battery change

    update: according to other threads the important measurement is actually the INNER diameter (not outer) and it's not metric but rather 3/4th inch (0.75 inch) which is about 19.05mm

    however the thickness is the problem, the factory one is some weird number like 1.168mm and 1mm rings are too thin while 1.5mm rings are too thick, you have to find something inbetween and they cannot be "hard" material but softer silicon, etc.

  • I used the original O-ring, lubricated and sealed with additional silicone grease. Petty standard stuff for diving gear. No reason for it not to work on a sweaty chest strap.

  • you are missing the bit where the original ring gets deformed either from the opening or closing of the case

    it's an extremely well documented problem on the HRM-Tri and I suspect the Pro and Run are no different

    the batteries die because the unit then gets either a constant low level short or is constantly turning on instead of sleeping

    you can see the current HRM battery voltage in every activity FIT file if you use a decoder, every day it drops way too much after the first battery change and the O-ring gets deformed, once it drops below 2.95v or so that's the end of that battery

    if you look at the O-rings in other brands of HRM straps they are much more heavy duty

  • Yes infiltration could be the reason for this, I thought so too. I think that more than the deformed o-ring it depends on the fact that the battery compartment was sealed with some substance and opening it breaks the seal, too bad that Garmin does not inform about this. I will replace this band under warranty and at the next battery change I will seal everything as eezytiger says, if i'll find an o-ring i'll change it too. Hrm Pro and Run are identically.

  • the fact that the battery compartment was sealed with some substance and opening it breaks the seal

    Not the case. There is no substance used to seal the case, only the seal. If that is not put back correctly then problems can occur.

    Two things I have done with any strap:

    • Immediately I get the strap I've removed the screws and placed a dab of silicone grease in the threads
    • I put a thin wipe of silicone grease around where the o'ring sits - note there is no evidence of any other sealant at this time.

    As others note, it is important that you ensure the o'ring is sat properly before refitting the cover. It also helps if the four screws aren't tightened down individuality but sequentially.

  • I must say that already with the first strap I always carefully replaced the batteries, making sure that the ring was well positioned and I alternately tightened the screws, in short, I did the best I could, only I did not use silicone or other sealant. However, in an object that costs 120 euros it is incredible that the customer has to replace the ring or put silicone and so on at every battery change, even on new straps, otherwise it breaks, it was not really possible to design a better battery compartment, well sealed by a small lid? Like the Polar straps for example, I'd like to know if they have the same problems ...

  • I had three HRM-Run straps so far, my second one failed in the exact same way: it started draining batteries within 1 day. It was still under warranty and got it replaced.

    All my HRM-Run straps started at some point building up moisture within the sensor housing, but I if you recognise it soon enough (typically you can see signs of moisture through the transparent case) and dry the unit, it continues to work but you cannot expose it to water.

    The problem for me has always been small cracks in the sensor housing. At some point they are clearly visible, but at the beginning they are barely noticeable - still sufficient to let water in. It might be your case as well.

  • The solution to the problem would be if Garmin simply included the rubber rings in the Garmin store and everybody could order them cheaply if needed.