On the edge like that there are so many variables that come into play. Accuracy of the voltmeter itself, the quality of the solder work, an MCU operating at the better end of it’s spec vs the worst end, how snug the battery fitting is, etc, etc.
Not an exact science at all.
Where are you getting your batteries from? I got mine from Aliexpress (mistake) and they drain significantly faster than the ones I got from my local supermarket. However the ones from the supermarket are significantly more expensive - I guess because they’re not counterfeit.
I have seen a single genuine CR2032 run a temperature sensor for over a year an still report 30%. Other times I’ve seen a temperature sensor report 1% battery and run for months.
Here’s the tread for the Xianomi/Aqara battery values.
(Xiaomi) Batteries values are questionable · Issue #8499 · Koenkk/zigbee2mqtt · GitHub
Personally I buy name brand batteries from my local store. I’ve had good luck with Energizer batteries in my Tuya temp sensors. I’m sure those will work just as well with the Aqara sensors.
I received 12 new Aqara temperature sensors last weekend. I installed them, and have noticed that they all dropped to about 50% of their starting charge in the first 2 days. That being said, one I’ve had for months has sat all week at 33% (with a couple of times reporting at 36%). After dropping, they’ve stabilised at a new value. I believe the calculations for battery life are incorrect… so I’m ignoring them for now until they get really low… then I’ll look to replace batteries.
I got one of these 2 days ago. I had to rebuild my homeassistant, I couldnt get the device added. It seems completely dead… I ve swapped batteries etc, but the device is dead, no BLUE led blinking etc.
Is there something I can do other than try another battery?
The first time I added the device it worked like a charm. Strange.
Eric
PS: Im totally new to this but Im liking it.
I got mine around the same time as you. No problems with it so far.
I would make sure the battery is making good contact. Remove the battery cover. You should see a metal tab on one side of the battery. Pop the battery out and slightly bend that tab in. Be care not to break it. Pressing the button the LED should blink. Pressing and holding the button should reset the sensor then put into pairing mode blinking the LED rapidly.
Hopefully that helps.
I just got these Aqara temperature, humidity and pressure sensor and I am having the same battery indication issue here. I am glad to hear that it might just be a benign reporting issue, versus a flaw with the device. I will keep monitoring mine and update here.
@hruharhwa I found that there are a lot of knock-off CR2023s on the market. They look legit but seem to run out within a few days/months, especially if you’re using them in cold climates. If you have no other choice, just buy these batteries from a reputable store rather than off ebay/aliexpress/amazon which seem to be absolutely flooded with fakes.
I am on a mission to get rid of all sensors in my home that use non-rechargeable batteries, or convert them to use rechargeable batteries repurposed from failed packs. Not only are good CR2032s expensive, but they just end up in the landfill once you’re done with them.
You can run anything that takes a single CR2032 (3.2V ish) straight off a single LiFePO4 cell. These typically have a charged → spent voltage range of 3.65 → 3, so it’ll power most of these sensors that draw next to no current for years on end.
I run mine off a standard LiIon cell though, the kind that has a working voltage of 4.2 at fully charged. I charge them up to 4.1 volts using a variable voltage charger, then put a diode in series with my temp sensor’s power feed to drop the voltage by 0.5V which brings voltage down to ~3.5V which seems to be low enough not to fry the sensor.
I tried 3.3V LDO but the LDO itself consumes too much power and the battery dies in under 3 months. Perhaps a different diode could be used (or multiple in series) if you’re worried this voltage is too high.
I got rid of these sensors and replaced them with LYWSD03MMC (BLE) and ditched Zigbee for ESPHome (this way I can put temp sensors anywhere with an internet connection, plus I found zigbee kind of temperamental) - but if you so choose this BLE sensor can be connected to Zigbee apparently: https://www.reddit.com/r/homeassistant/comments/17jsq7m/converting_xiaomi_lywsd03mmc_temperature_sensor/
