Twice today while moving the core between locations with significantly different temperatures 73deg - 47degf . It lost wifi communication and could not recover (flashing green led). I was only able to get it to reconnect after removing the battery letting it soak at the new temp then repowering. My guess is the major temp shift creates some problem for the wifi module. Has anyone seen anything like this?
Since you haven’t specified which way, but in most of the cases, it is likely caused by water condensation when moving from a cold dry place to a warm wet place. However, if it happened in both directions (cold<->warm place and dry), then it could be some soldering defect or bad connections due to a different materials expand/contract faster or slower.
Personally, I don’t have issues when moving the cores between a difference of 20~25 degC at the relative humidity of ~35% to 55%. Anything more humid I would not power up the cores until after may be an hour in the direction of warm -> cold.
@edwintam Thanks for your ideas about what might be causing the issues. I have had the problem going both directions.
I am wondering now if it is related to weak batteries. In both cases not very long after the problem 10-30 minutes I had to replace the batteries. I have been logging lot of data to a server every few minutes causing the drain on the batteries. I would guess though if it was battery related the problem would happen going from room temp to cold, not the other way around which I also saw.
I will add a followup if I see this again.