Battery Amusement

[paulca]

I have about a dozen battery powered sensors for temperature/humidity.

In the spring the kitchen sensor stopped sending data.  It's battery was flat.

Then in June it sent a single sample, "21.0C" and died again.

The office sensor and bedroom sensor are now following suit.  They go incognito for days and then on a nice warm day they find enough voltage/residual power to power up and send one sample before dying.

The kitchen came back yesterday again, this time for 22.0C.

The sensor I put into the fridge worked perfectly until it got down to 4C, when it died after 2 days.  However, when I raised the temp i the fridge to 16C it started reading again normally.  It read normally a whole week until I "cold crashed the beer" and this time it cut out at 5C.

I just find it amusing how coin cells can have "elasticity" and "bounce back" which is temperature dependant over months!

Downside is, I need to order even more big fat coin cells and go replacing batteries.  They all get replaced at the same time to keep the endevour compressed.   To date it's about once every year for the temp/humidity and once every 2 years for motion sensors.