I know this was a hot topic for xx.12 firmware, but I am on xx.20 and literally just replaced the batteries in my garage door sensor and motion sensor 4 hours ago. Want to know the battery percent right now???
just replace them when they die.
ROFL, wow that’s a record. BTW, what brand/type is it? Just wondering if the temperature has anything to do with it.
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what kind of batteries are these devices using?
They are the SmartThings sensors and I have been using them for two years without any issues in the garage…until recently.
They are the CR2450 batteries.
I took a look through the events. I replaced the battery (lithium) at 5:43PM and the logs show 100%. Then at 6:14 they show 33%.
If you have a multimeter, I would check the battery voltage to see if it actually drained so much or it’s a faulty sensor reading.
Wondering if the temperature has anything to do with it.
One way to test it would be to remove the battery, keep it inside the house for a day until the temperature is normalized and then put it back in the sensor and see if shows 100% again, if so then it’s the temperature.
it appears the sensors are still functioning. I suspect, as RBoy indicated, that the increased resistance at low temperature is causing the low battery indication.
As batteries discharge, the voltage decreases and it is by applying some formula to the measured voltage that the system determines the percentage of battery remaining, which is not directly indicative of how long the device will continue to function.
I would recommend leaving the batteries in and monitoring it to see how long the battery really lasts.
to monitor devices, I use the The Simple Device Viewer smart app, which has a feature to send alerts when devices have not sent events for some period of time.
Yes - it is possible that the temperature is playing role, but would that be more of an issue the older the sensor gets? I have been using these sensors for two seasons in the garage, and until the xx.12 firmware update never had any issues like this. The batteries would show normal for months or longer without issue, even during the coldest months of the year.
So as the actual sensors “age” (not the batteries themselves, the actual sensor) would that cause them to discharge differently or report differently than they have previously?
And I will check with a multimeter.
I will throw my hat in this ring and say I’ve witnessed the exact same thing on MANY of my sensors. Both ST and Iris sensors just nose diving after a change. And I have taken the cr2450’s to a DMM and do not see them as dead. I have quit changing them and just wait for them to die, ignoring the low battery alerts. These are all with known good Panasonic, brand new out of the blister pack, cr2450’s. Known good because we know some models are poorly designed and dont make good contact with the terminals. I have been using these Panasonic’s for the last 3 years.
When probed with a DMM, I see no less than 2.9v in all my reports of low batteries. And even at a -10c curve, panasonic has the life much greater than… 3 days. Most of my battery reports have went from 100 to 1% in just a few days.
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No, it’s a function of the battery itself. Did you change brands? It could be a bad batch.
The way to tell if the sensor is going bad is to measure the battery voltage, if it’s high then the sensor reading is off. If the voltage truly is low (and you’ve ruled out the temperature issue) then the sensor is going bad and consuming too much power.
I have used both Panasonic and Energizer. And I will check the voltage. I know that they aren’t really completely drained as I left the previous battery in at 1% for a long time.
My OCD can only handle low battery notifications for so long 
I might end up buy a new multi sensor just to see what happens. The new ones are pretty cheap.
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LOL - I think that makes me feel better? 
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Does negative 33% means the poles have flipped? Negative is now positive? lololol
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Hopefully! That means that the battery is now recharging. 
is it increasing or decreasing over time?
Increasing negatively…
Was 1% for the longest then flipped to -11% and I was like wth?!
I typically disregard battery readings and just wait until the device stops working. Been waiting for months for this one to kick the bucket but it just keeps going further and further into the negative realm.
It’s a Visonic Contact with a Panasonic CR2030 I believe. Same sensor on one of my Dayroom doors and I am replacing the battery in that one every couple of months while the sister door in the same room hasn’t been replaced in 2 years…