When you look at the graph, battery voltage drops from 4735mv to 4432mv at the moment of signal loss. Maybe this gives an indication for the faillure. Still glad that i have te opportunity to dive into this issue, cause when units are out in the field, cost for replace and reputation damage, will be much higher.
Temperature is now -20 C + , so we passed the critical point. Lets wait for at least an hour, to be sure there are no problems with this sensor.
Battery is slowly recovering, but voltage level is still much lower than normal. Temperature outside the fridge will be around +10 C.