Hi - I use a fairly old (maybe 10 years) Polar HR monitor, that uses CR2032 batteries (the little coin-shaped ones). It seems to go through these batteries at an alarming rate, almost one every 3-4 weeks. Might be time for a new one. Any recommendations welcomed - doesn’t need to do anything other than Bluetooth my HR to the iPad for Zwifting purposes.
Thanks.
All the Polar HR sensors I have had use CR2025 batteries, I guess it is possible yours may have suffered excess sweat damage from the battery compartment lid not sitting where it is supposed to… As far as I know, Polar H10 (or H9 if you don’t need ANT+ or standalone operation or the other bells and whistles) is still the gold standard in HR sensors.
Thanks Anna. The battery cover is absolutely tight as it can be, and it kind of sits off the skin slightly anyway due to the strap. I think it might just be reaching the end of it’s life, which often happens with battery-operated tech.
Not familiar with the Polar units but 3-4 weeks sounds like it’s not either shutting down or going into sleep mode. Do you (or can you) disconnect the strap when not in use? Like I said, not familiar with them.
As to alternatives, I’ve used a Garmin in the past, then moved to a Wahoo 1st gen a few years ago (primarily because it was a freebie and it has LEDs - useful to at least see it’s alive).
I’m struggling to think when I last changed the CR2032 batteries in either of them. Certainly many, many months - used ever 2nd day.
Both have been solid in their connection and both have been trouble free.
That’s what’s making me think it’s dying. I’ve the same battery in the cadence sensor and haven’t changed that in years - obviously used just as much as the HR one.
It doesn’t have a sleep/on-off mode.
Hopefully others will jump in with alternatives. My experience isn’t exactly worldly 
But these have worked for me.
I’ve just changed the first battery that came with my Wahoo Tickr because it was flatlining at times and a few people here suggested it was probably running out. Only done a couple of rides but touch wood seems to have sorted it. I’ve had it three years.
Am not in the UK, but the big name brands are pretty universal. I’ve been running a first gen Wahoo TICKR and a Polar H10 as a backup for almost three years, swapping between them every once in a while. I still haven’t had to change the batteries in either, and I’ve racked up over 676 hours in Zwift itself, so even more than that actually wearing the HMs. I would recommend either without any reservations.
AFAIK, both models go into sleep mode soon after the chest strap circuit is broken. Only getting 3 or 4 weeks out of a CR2032 is a bummer. Definitely worth getting a new unit if there’s no evident damage or easy repair to your older Polar. In the long run, it would cost less than the batteries you’re going through!
(I recall someone in a thread about two months ago mentioning being able to buy coin cells for less than a Euro per article, but where I live they are far more expensive, even in bulk.)
(A pack of four costs just over an euro in pretty much any supermarket here and this is approximately the most expensive country in the EU.)
One other thing to consider might be just the textile part of the strap, in my experience they are the most fragile part. For me the failure mode has always been an unreliable connection, but I guess it is conceivable that you might have one that instead leaks current across the terminals, preventing the sensor from going to sleep. I prefer generic ones (something like a tenner on *m*z*n) to original Polar straps.
But still, in this day and age, I guess 10 years is already pretty good for a piece of consumer electronics…
You might be right Anna - I can’t say for sure that the battery needs replacing, only that all of a sudden HR is not being sent to/picked up. Buying a new battery might be the answer, though it may be that the connection itself is falling off.
I wonder, in this age of rechargeables, do any models come with that option? I know CR2032’s are cheap, but anything to keep more landfill out of the ground would be welcome.
(Off main topic)
Hi, @Anna_Ronkainen. Now that I think about it, you were the person I was thinking of mentioning the low-cost batteries previously. I’m Swiss, so not in EU, and prices for batteries in supermarkets are at least triple what you pay in Finland. But cost of living here is generally 75% higher than Finland according to stats I can find online. 
been using a wahoo tickr v2 for the past close to 18 months, had an issue with the strap last year reading really high/incorrect HR data but wahoo sent out another free of charge, battery life is every few months depending on use
I used a Polar out running and that was fine, although I got a Garmin watch in a sale so use that now.
For the bike I use a Garmin Strap (flexible) and a Bryton sender, why you may ask, my Bryton strap was the older stiff material type and not very good so I swopped it for a Garmin about 3 years ago, I go through batteries about two a year.
Batteries will always be an issue, I do make sure that I rinse and dry the strap, sender and connections after every ride.
Ah yes, Switzerland and Norway are about the only countries that actually feel consistently overpriced to me. Looks like even IKEA wants CHF 6.95 for a pack of 8. (Ideally a part of that would at least be due to a pollution tax of some kind, but probably not.)
And yeah, I find having to deal with disposable batteries annoying as well (having to cover used batteries with tape to not create a fire hazard is a bonus annoyance as well) so I would certainly be interested in a rechargeable sensor as well, but I have never heard of such a beast.
hopefully you aren’t buying cheap batteries off ebay because those are terrible. you wouldn’t think people would bother to fake batteries for a 0.00005p profit margin but they do
with that said, pretty much any modern HRM is good and fit for purpose. garmins are known for their battery life, i use a new generation tickr personally.
(a new) Polar 
I have a Polar H10 and zero regrets. Had it for about three years.
I had a similar problem and by changing the battery, it would work for awhile but then get wonky.
I noticed the 2 terminals were no longer the same silver color so I started cleaning the corrosion off with fine sand paper and that worked for ,6-8 months and finally I just bought a new CooSpoo.
Also, I bought 3-4 straps and each time, a new strap seemed to work for a while but then not work.
New CooSpoo, no probs and same battery as shipped for over 18 months.