I get regular a Unjustified low Battery (1%) alarm from Aqara T1 temperature sensors (Zigbee protocal) and Remotec scene master ZEC-90 (Zwave protocal). And after a short period without any battery change a new message that the battery is full again. I still work with a Homey 2019 version and have several battery powered devices. But only these 2 devices show this behavior.
I have this behavior last months , never happened before. Is this caused by a Homey upgrade???
On my homey 2023 several aqara devices, temp T1 ones too, show this phenomenon. Think it happened with some zWave Devices too. Tend to ignore that. Happenes since a year or so. Must see if the sudden drop is caused by activities by the device. A bit difficult. Haven’t bothered sofar to verify if it‘s limited to specific devices. As I only keep weekly stats such negativ spikes go unnoticed.
A lot of Aqara battery devices don’t really measure battery percentage directly. They mostly report the battery voltage, which then has to be translated into a percentage or battery alarm. And Aqara certainly isn’t the only one doing it this way.
The problem is that coin cells like CR2032s have a very flat discharge curve. They can sit around the same voltage for most of their life and then drop quite quickly near the end. Temperature, load and battery brand can also affect the voltage.
This is also why you can sometimes see an Aqara device flipping between battery empty and battery OK. When the device transmits, the extra load can briefly pull the voltage below the low-battery threshold. Once the battery is resting again, the voltage recovers slightly and it reports OK again.
I can usually use my Aqara Light Sensor T1 to tell me when the heating is turned on. The temperature fluctuations make the battery voltage jump up and down, and I get this exact behavior.
So the battery percentage/alarm on these devices is really more of an estimate than an accurate measurement, especially when the battery is getting close to empty.
