The battery on one of my SmartThings multipurpose sensors got to 1%. Everything was still working when I changed the battery. The device did not come back after the battery change. I’ve tried a couple battery. Since it won’t connect, the only clue I have as to what’s wrong is that when I press the reset button on the inside of the unit, the little led in the hole next to the reset button lights red for as long as I’m holding the button. Is this a dead device?
What brand battery are you using? The SmartThings branded multi purpose sensors are notorious for being picky on battery brand. I believe Energizer are the ones you to NOT want to use.
I admit I did first try an off-brand battery but then switched to a known good Panasonic battery. I was aware of the pickiness but I did not think that include the risk of damage to the sensor.
I read some other threads (e.g. SmartThings Multipurpose Sensor Battery) and learned that the issue is mechanical, not electrical. I compared my cheepo “EBL” batteries with the Panasonic and don’t see a mechanical difference. I put one of these new EBL batteries in another multisensor that needed a new battery and that one is happy about it. There must be something else going on with the first sensor.