My freezer has a bad habit of icing up. It’s not a great design to start with and I suspect I’m overfilling it, but I wanted to check whether it was getting down to the right temperature and also whether the defrosting cycle was running properly. A Pinoccio is an ideal thing to check this with, the only problem is Lithium batteries don’t like working in cold temperatures. At -20°C the chemistry inside the battery is finding it really tough going – after a short trip into the freezer my Pinoccio’s battery was reporting 4% even though it was fully charged moments ago.
There is an alternative though, a supercapacitor. Capacitors don’t particularly care about the cold since they don’t rely on a chemical reaction. Capacitance is simply an electric charge difference between two conductive plates that are close together. Supercapacitors with an industrial temperature rating (-40°C to 85°C) are quite common.