I posted this question on Amazon with the answer embedded. Earlier, someone said that Alkaline AAA “lasted all summer”. OK, fine, but I had to post another “question”, but this time with the ANSWER, which is the following:
Q — FREEZER temp – WHICH batteries??
Lithium = ++ $cost / 96% –
Alkaline = 33% – [Seems to me that only 33% effective won’t cut it.]
NiMh = 86% – << THAT is best!
I had asked separately: Will alkaline AAA batteries work ok at freezer temps? – for a few months, rather than lithium? – asked on February 14, 2023
Hopefully, my TWO - IBS-TH2 PLUS with TEMP probe will work through the metal case of my refrigerator / freezer. But, if not, it should still record the temps and I can sync them later. I’ve either got a defrost problem, or a fan at either the compressor coils or evaporator coils that is intermittent. Once I get that working properly, I plan to permanently mount / place the probes both above, and below my evaporator in my HVAC. The diff should be ~ 20F when working properly, and if it gets to 12F, then that shows a Freon leak. I also have an ECOBEE 3 that records the status of fan, stage one and stage 2 AC.
If it is used in the freezer, we recommend the IBS-TH2 rather than the IBS-TH2 PLUS.
The IBS-TH2 PLUS body is not cold and water resistant.
The IBS-TH2 has cold and water resistant and the alkaline batteries are sufficient for its work.
Thanks— Got it — For now, I will keep it inside a zip-lock bag to ensure no moisture drips on, or condenses inside it. Alkaline batteries should be OK, since even at 33% of capacity they should work to deliver over =+1.2 v for a few months. (I’ll still use my NiMh, assuming 1.2v is fully enough for full Bluetooth power.)
The Zip Lock bag would be essential for me, until my freezer works as it should and doesn’t drip or thaw. I tried my ECOBEE remote in a bag, but the bluetooth couldn’t reliably penetrate the steel and then 20 feet to the thermostat. Hopefully, this will work and reach my phone / tablet. But if not, as long as it records first, I can simply remove it, connect to the phone and get the data, (leaving it in the bag until it warms up). The other alternative is to put only the probe in the freezer.
TIP – Anytime you plan to move ANY device from freezing temps, and it can get air inside the device, as that air is replaced from the more humid room temp air, it WILL condense on whatever is “much colder”. Best, would be to zip lock bag any device with cold or minimal air (and or add a desiccant), and don’t open the bag until the device itself warms up. The water resistance method is sometimes designed to keep water out of a device, and sometimes the components inside are coated so they could get wet for a short period of time.
(Seems to me any “standard rating systems” should indicate which method, since with the first method of keeping water out would be ok even in salt water, but fail within 1 second if any sea water touches anything inside, while YMMV if sea water touches any coated components using the second method. We “rinse” plastic SCUBA gear, because it is also affected by corrosive sea water.)