My contribution for today.
I have Samsung multi-sensors but some are located in cold places: fridge, surgelator, mailbox , and outside places (Canada here, -30C / -22F in the winter).
So the button cell 3V won't last for long...
I have plenty of common 18650 Li batteries. I connected one in a battery holder, added a 3V regulator and I have now a perfect external battery and I'll monitor how long a 18650 battery will last.
source:
Regulator : 5 PCS 3.3 6V to 3V 3.3V DC DC Converter Step Down Power Supply Buck LDO Module Voltage regulator Board|Inverters & Converters| - AliExpress (1$ each)
result: