This is second generation of my outdoor temp and humidity sensor.
I build the first generation in September 2022. It was based on SNZB-02 and single CR123. I made 2 pc of them.
The battery last for almost 1 year including winter time.
Now with new SNZB-02P I wanted to do it with mega power supply. 2x CR123 connected in parallel mode.
Hope current config will last for 2 years or even more…
Maybe Sonoff could make factory version of external SNZB-02P with mega power pack.
Nice work!
Thank you
Any specific box model?
Humidity is not a problem?
This one is for the box
115x85x35
This one is for the mounting plate (one plate is enough for 2 boxes)
200x150mm
Box is dry inside no matter what.
But it is not the proper way to measure humidity by meteorology station standards.
I have professional weather station (connected to Accuweather network) nearby and sometimes my humidity levels during wet days is around 10% higher.
But temperature measurements is very accurate as I have 1 sensor at the front of the house and 2nd is at the back. So I can measure temp in the sun and in the shade at the same time.
For example at this exact moment AccuWeather station from my area is showing temp 22C and real feel temp 24C.
My front sensor (sunny side) is 25.8C and back sensor (still shade side) 23.6C
Power supply and usage comparison
SONOFF SNZB-02
original battery CR2450 capacity is 620 mAh to 2.0 volts but for Sonoff it will be less that 630mAh because sensor will stop working at 2.6V
I used in old project with this sensor 1x CR123 which capacity is 1500 mAh to 2 volts and again the capacity value will be smaller as this sensor will not work at 2 volts.
Now the new project and sensor
SNZB-02P
original battery CR2477 capacity is 1000 mAh to 2.0 volts but for Sonoff it will be less that 1000mAh because sensor will stop working at 2.6V
I use 2x CR123 which capacity is 2x 1500 mAh to 2 volts and again the capacity value will be smaller as this sensor will not work at 2 volts.
With the new sensor model Sonoff is promising 4 years of work on CR2477single battery of 1000mAh capacity. I used 2x CR123 which is total of 3000mAh.
Does mean that I will have to replace the battery after 12 years? NO.
With old project the single battery CR123 last for almost 1 year including winter.
The new project… just started working yesterday.
But there will be huge difference for temp and humid sensor to work indoor and outdoor!
I can compare how often reports are sent with temp and humidity data from my SNZB-02P indoor sensors and from outdoors. The difference is huge. Outdoor sensor are sending data much more often as the values of temp and humid are changing more often.
The frequency of sending data will have biggest impact on battery usage.
The last factor is winter… for sure low temp have negative impact on battery life.
So… with SNZB-02P and 2x CR123… I hope for 2+ years of work. Probably the new sensor is more energy efficient and I provided mega 3000 mAh power supply.
Time will show the answer.
