Thank you to those who responded to my request for information about HOBO pendant data-logger survival at temperatures below the advertised limit of -20C (posted Jan. 31, 2013).
Here is what I have learned: - One researcher has successfully used these loggers to record temperatures under snow through alpine winters, but they aren't exposed to extremely low temperatures because of the snow cover. - Another researcher has used them in the field in Alaska. They have reached temperatures as low as -46C, but that appears to be their absolute lower limit (the temperature flat-lined thereafter). This person has not seen signs of battery leakage, but HAS had "bad battery" warnings at low temperatures. He suspects short periods at -26C would probably be OK. - In my own further googling of CR2032 batteries, I've noticed that some vendors list them as being good down to -30C. - At the other end of the scale, one researcher has logged temperatures up to 54C (130F). - A researcher working in the Arctic has used the HOBO stainless U12 unit, which is rated down to -40C. It seems that it worked fine, but according to her, the unit doesn't start back up on its own after it's been exposed to that temperature--worth keeping in mind. In the end, I have gone ahead and ordered a bunch more of these pendant light+temperature loggers, and I'll be deploying them this summer in Canada and Colorado. People are welcome to contact me in future ([email protected]) to find out how they've survived! Jessica Forrest Assistant Professor Department of Biology University of Ottawa http://mysite.science.uottawa.ca/jforrest/
