I’m having a strange version of this. I have a battery notification piston (webcore) that let’s me know the battery state of all devices. In my sunroom I have two of these. One SIPS battery very slowly. The other starts at 100% and by the next day or so is at 1%.
Now here’s the strange part. It can stay at 1% for weeks. I’m wondering if this is different from the above or the same issue and people just didn’t realize it might be the sensor just being horrid at reporting battery life. I only replaced my batteries as I was tired of seeing the 1% alert all the time and assumed it was a bad set. Nope.