18650 Li external battery holder and 3V regulator

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.

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)


Will be interesting to see how the battery performs. BTW your regular is a Linear not a buck converter. Lets say the AliExpress description was a little overzealous. However for this application the linear regulator is really the way to go, due to the low current they need to operate.