Recommended battery?

I just got my Ruuvitags (cool!), however one of the tags arrived with a dead battery. The plastic film was in place, so it seems like an empty battery was installed in assembly(?). The tag itself seems to be OK, when I tried it with the battery from one of the other tags.

I’m wondering what is the correct type of battery to use though. Your site says CR2477, but the failed battery is a CR2450HT. Which one should it be? Does it make a difference which of the two to use?



I’m sorry to hear about the dead battery. We’ll look into how the battery has failed prematurely, thank you for reporting the issue.

CR2450HT is extended temperature range battery. Personally I’ve used a basic CR2450 from nearby hardware store (Clas Ohlson) both in freezer and sauna with no issues, however CR2450HT should have linger life in extreme conditions. CR2477 batteries work well also, and they have better capacity which leads to longer lifetime of the device.


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Thanks Otso. I’ll get one of the regular ones.

Hello! Do you have any idea, where to buy those extended temperature range batteries from? They seem to be impossible to find in Finland. Ali sells thousands of them (minimum order 10000 or so), but I only need one or two…:wink: Ebay has a couple, but postage is just ridiculous. And btw, is cr2450HR and HT the same thing?

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Different manufacturers name wide temperature range batteries differently. I think CR2450HR is a product of Maxell.
Normally wide range batteries are used in car tire pressure measurement system. I have not checked but they might be available in a car repair shops.

How wide temperature range you need?



One would be for the outside, which means something like minus 30C and the the other one for sauna. In my case that would be up to +80C.


We will consider to stock later also wide temperature range batteries. However shipping of batteries is very challenging and we might be able deliver them only to Finland (and maybe Europe).

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I noticed that one of my RuuviTags stopped updating in the app, and it’s the battery that suddenly went empty. Last update on the Android app was some time around 01:00 last Saturday. The reported voltage was 2.5 (don’t remember the 2 last decimals). This Tag has been in a greenhouse the whole summer until now. The greenhouse was emptied a couple of weeks ago and all windows have been closed since then. I noticed earlier that the plastic of the house was constantly wet on the inside. Could it be the constant extreme humidity that killed the battery some time during that night? I tested the Tag with another battery and it works :slight_smile:
Another Tag that I have outdoors since beginning of summer reads 2.887V. Those both Tags were activated in late May. The Tag that I have active in this room since I got it in February reports 2.857V.

2.5 V sounds relatively healthy battery, it’s a bit curious that it has died already.

Humidity might have been a factor, there have been a few reports of tags in sauna suffering from battery issues too. If the greenhouse gets really hot, that’s another contributor. High temperatures increase battery consumption, but this starts to be a sever issue at 80+ celcius.

It’s a small greenhouse, so temperature during warmest period of summer is normally just a bit over 30C during the day. We try to cool it down with sprinklers, when we have time for it, but not every day. The Tag seemed fine the whole summer so I thought the IP68 rated enclosure seemed to be very good. So I find it very strange that the battery died over night or at once some time during the night.

Has anyone found a place to buy a battery that can take -30 (normal outside winter weather in Finland)?

Most of the standard CR2477 will work even they are rated to higher temperatures. Normally in Finland temperature is now always -30C in winter time.

This is one option which is rated to -30C if I remember right.

Does this CR2477/P fit on ruuvitag? And is this recommended use also in +80°C Sauna? Default battery seems frozen everytime when heat get over 65°C and device not send data at regular interval.

Any 3 volt 24.5mm diameter coin cell CR2477 battery can be used. Please check manufacturer’s datasheet to make sure it’s specified to work at high temperatures. We’ve also some high temperature batteries available. If interested to purchase some, please email