Looking to get notified when my mailbox is open. Mailbox is within 30feet of a zigbee lightbulb so I dont think range is an issue, but when I used a Aqara vibration sensor, once the cold weather it, it killed it quick.
From my limited reserarch, it seems AA, AAA lithium batteries perform better in the cold. I just picked up this Yolink LORA contact sensor but dont love thats its cloud. But it is powered by two AA batteries.
Do they sell zigbee contact sensors that use AA, AAA batteries as opposed to the coin cell?
What you are probably looking for are Ni-MH (LSD) batteries, they can even be charged at negative temperatures.
Sounds like li-coin cell type? They can’t output the 3V for long even when full if temperatures drops to much. So they probably only output 2.xV which “tricks” the firmware on the device to report a empty battery while they still are able to deliver some current to keep the device working.
My findings regarding typical Li-coin cell type: They easily (self)discharge around twice as fast in cold(er) environments. Most important the fact that the voltage drops quickly in the beginning, like 0.1V per day resulting in maximum voltage with a full battery to be only around 2.6V after couple of days in the fridge. Depending on the device broadcasting can be come unreliable quite quickly at some certain (low) voltage.
Example of quick voltage drop in cold (still positive) environment with a full coin cell li-type battery
PS.: @nappyjim maybe tell us what your “cold weather” is, things like expect minimum temperature and humidty for example
I live in central Minnesota in US. Average winter month temps are 20’s F but it can get as cold as -30F some days. The unit will be in the mailbox so it won’t be exposed to the wind at least.
For battery I was thinking of getting Energizer ultimate lithium batteries.
@tom_l I think it’s cold because it lasted longer in the summer. But it was a vibration sensor too so who knows if during winter because it’s windy, it had to keep reporting those vibrations caused by wind?
I use that YoLink contact sensor with lithium batteries for my mailbox.
I haven’t had any issues. The batteries are 2 years old and still strong.
I’m in New Hampshire and winter temperatures are similar to yours, but
We rarely get below zero.
Those “bunny batteries” are the choice for weather station owners in sub-freezing climates. I’ve had sets last almost five years outdoors in temp/hum/barometer/lightning sensors, where Duracell alkalines would not even last a year.
The only pitfall to the Energizer ultimate lithiums is that they have a very flat discharge curve through their entire useful life. While that seems like a good thing, it makes battery-change planning difficult because they give little warning before their voltage drops off a cliff when they die. I used a set in my front door deadbolt, and they only had enough juice to unlock it twice after the low battery alert triggered…
I have one of the yolink indoor motion sensors in the back of my mailbox, with a AAA energizer lithium battery in it. It lasted all last winter no problem, and still going strong right now.
Wow! One of those little square ones that uses the 2032 battery? I have a couple of those and they eat batteries rapidly for me in more ideal conditions. That’s impressive!
How hard is that rule or is it just a suggestion. What about a small solar panel pointing south west to get a little charge later in the day when if there has been sun it could warm up the cell a bit first.
There seems to be conflicting information. Lithium batteries like the bunny sells are disposable, and great for use in arctic temperatures.
Lithium-Ion batteries are rechargeable, and don’t like to charge in the cold. Every time that you see an e-bike fire on the TV news, this is what they use. They are also banned from being shipped on some commercial cargo jets.
LiFePO4 batteries have most of the benefits of Lithium-Ion, but are not prone to fires. They are increasingly being used in off-grid solar storage systems, but require heaters and battery management for hot/cold weather…
