Phonak Marvel M90-RT shutting off in cold weather

I’m new to HA, I have had my Marvel 90RT’s for about 4 weeks and they have worked very well, although I’m still trying to get them adjusted to the best sound. Today the temperature here was in the 30’s and I had to be out side for several hours. My left HA powered off and would not manually turn back on until I got home and dropped it in the charger then after about 10 seconds the light started flashing green indicating that it had a good charge. I took it out and it worked as it should. I checked the charge percentage and it was showing the HA that worked all day was at about 60 percent and the one that had shut off was at 80 percent. Has anyone else had this issue? I’m wondering if it’s just with the rechargeable HA or if it happens with the replaceable battery powered HA also. I understand if it was extremely cold however in the 30’s I would expect them to work.

I live in Central Oregon, where 10-30F is commonplace; I’ve never had an issue with the Marvel rechargeable HA’s turning off. Something must be wrong with yours.

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Very similar issue here.

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I don’t see a specification for operational temperature range for the Marvels in the manual I could find on-line. I did see a 5 C minimum operational temperature spec for an earlier Phonak Audeo - that is 41 F. You might ask your Audi what the minimum operating temperature is - they should be able to find out from Phonak if they don’t know.

For my Oticon OPN S 1 aids (typical 312 zinc air battery), the manual that came with the aids (and is on-line) specifies a minimum operating temperature of +1 C (or about 34 F) with a maximum of +40 C. The storage and transport temperature range is much wider (-25 to +60 C). For the rechargeable version of the OPN S, the manual lists an operating temperature range of +41 to +104 F. No idea why the rechargeable version would have a higher minimum operating temperature. Of interest is a comment about the best charging conditions being between +41 and +95 F.

I do not know what battery is used in a Marvel but I did find a Varta document on their rechargeable Lion small cells. The operating temperature range for charge is 0 to 45 and for discharge is -20 to 60 C.


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I know with my OPN1 ITE hearing aids that I haven’t had issues when out in 10 degree weather. But that is due to body head and headgear I am sure.

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This happened twice to me last year and was the main reason why I switched to the Marvel 90 13’s from the rechargeable ones… I was out in the sticks working with 3 offenders (I work with criminal justice) and both hearing aids cut out in cold weather, I was aware that they would reboot once I got home and put them in the charger, gave me a bit of a fright to be honest and it was fortunate that I had less challenging clients that day, but 6 hours or so with little or no hearing was not my idea of fun!!! So I switched to the battery Marvels… Cheers Kev:-)


Have you tried the Marvel 90 13’s in cold temperatures? If so did you have any problems?

I have not encountered any “Cut Out” problems since I switched about 11 months ago KS… Cheers Kev:-)

It gets cold here in Maine. We hit -8F last week but I didn’t go out. It has been zero F for the late-night dog ‘out’, maybe 15 minutes, and no problem with my Marvel. Personally, I hate cold ears and my head is usually double-insulated, which may matter. Yes, the two hoods (sweatshirt and parka) reduce sound but not much. Light ear-muffs might keep the aid near body-heat without cutting sound much, and you can lift a muff if you have to hear. One of those fur-lined all leather Arctic hats would keep your ear and HA warm but might be a lot of drop of external sound.

Another experiment would be to put it in a baggie and set it in the freezer.

A very extreme theory is ice in mike or receiver. They are well shielded but it would not take much. However you observe less battery drain which suggest a shut-down, not that diaphragms were jammed.

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The temperature wasn’t even that cold, that’s what worries me because there’s times that I’ll be out for several hours in temperatures in the teens and if they’re powering off when the temperature is in the mid 30’s they sure will when it’s in the teens. I even had on ear muffs when it shut down. I like the convenience of the rechargeable HA but if regular battery version would continue to work in the cold I would switch to using them before my trial period is over.

Chemical reactions slow as temperature decreases. We humans have adapted well to cold, but batteries do not. Years ago on all day ski trips, one learned to keep the Walkman inside the winter ski parka of bring 4-6 pair of batteries for six hours skiing. Behind the ear or in ear heating aids get body heat to help.

Here is a chart that shows what cold temperatures do to battery discharge rate. I have used Battery University for info for over 40 years, one of my permanently bookmarked sites!

I have experienced battery drain in cold weather with my phone and learned that I had to keep it close to by body for body heat to keep it from draining but the HA battery didn’t drain it just shut off and would not turn back on. The other one lasted all day. When I placed the HA that shut down in the charger it blinked red a couple of times then green. I checked and it had powered on and the battery was at 80% where the one that stayed on all day was at 65%. I’m just curious if it was the operating system that shut down or something about the rechargeable battery and if so do the 312 or 13’s do the same.

To answer that someone would need to test the hearing aids. I would go back to the clinic where you got them and ask, if they do not help, ask them to call Phonak. If they will not, then call Phonak yourself. It sounds like you have one that has a slight defect that cold weather brought out.

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It seems ODD that a rechargeable aid would shut off in the cold if the aid sits next to one’s head (like a heating pad right there) AND in colder climates a person would typically have a hat on. Being as utterly deaf as I am without my aids it would simply not be an option to have either or both of my aids shut off like that. Yipes.

I do recall when I had the Audeo B-Direct aids they’d reboot out of the blue here and there, now and then. Turns out a software update fixed that.

I’ve always had battery-operated aids (35 years now), due to my own needs. Altho many find the tiny batteries (mine are bigger 13s) a hassle to change every 4-5 days, they are typically a sure thing. Not saying that sometimes I don’t get a dud that lasts just a day … leaving me hobbled in the middle of the day. I always carry spares, but not on my actual person.

I sure hope the rechargeable issue is resolved! It’s like having one’s car engine fail in a MN snow storm. Nope. Would not like that.

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I should have noted that I use 312 cell, air/zinc.

None of these chemistries, at HA drain, should punk-out before your ears have severe frostbite. Yes they “do worse” in cold but not like you describe.

Another theory from this long-time gear fixer is a bad solder joint which touches well-enough normally but loses contact in cold (thermal contraction). Such a “joint” is intrinsically unreliable. In audio gear or computers, you’d have to smack it more and more frequently, and eventually even that does not fix it. In a warrantied HA, I’d think to invite trouble by wearing in cold, get at least three similar failures, well described, and talk to seller and maker about replacement.


My left HA (Phonak M90RT) went dead after about a week from receiving it. Provider sent it back to Phonak and convinced them to send brand new pair. No problems in the six months since receiving the new pair. I suspect quality control issues with Phonak.

I’ve not had a temperature issue with my Marvel 90r’s but If I where glasses on top of the hearing aids and a hat, it will sometimes press the toggle long enough to shut one off.
There is also a firmware upgrade that directly addressed a charging issue in which the hearing aid will shut off and not turn on without putting it in the charger and holding the toggle for 10 seconds or more. I definitely had that issue before the last firmware upgrade.

Living here in Canada, one would expect that this would be an issue. But with temperatures below freezing much of the time in Winter, I have not experienced it. If I did, I would probably go to my audiologist and ask about Heargear or similar protective sleeves to deal with it.