Purchased 2 RuuviTags to monitor freezer temperature in a boat. Neither will work in the freezer - loses connection. Freezer is 10 ft away from Cerbo GX. It is a stainless Steel freezer. Is the issue with the stock battery in the cold temperature or the stainless steel freezer blocking the bluetooth signal. Is there any work around for this?
Have you tested if you get the data to Ruuvi Station app or can synchronize the data? If yes, then sensors are working normally.
Are using Cerbo without Bluetooth dongle? If yes, that’s most probably the issue.
I have been working with wireless cold storage measurements previously and you already mentioned both reasons why it may be almost impossible to measure e.g. freezer temperature.
First is the temperature which may drop the battery voltage significantly and the second is the steel structure which blocks the signal. Depending on the structure of the door, there might be free route to signal through gasket but as the energy consumptions of the device is reduced the sealing structure gets more complicated and also blocks the signal more.
There are batteries that withstand cold temperatures and you may be able to use external (high gain) antenna on the receiver side to improve signal. Also putting the antenna very close to freezer may help.
I have monitored freezer temperature with RuuviTag now at least two months in my family house. It works perfectly. Freezer is normal chest type (metal outer walls) located in basement floor and signal comes via both bluetooth and Gateway to upper floor.