Do you replace batteries by time or as needed?

Pretty much the title...

Currently, I replace the batteries in all my HA devices annually, whether they need it or not. (A couple of my locks get a fresh set in the interim, but even those get replaced again during the annual cycle.) It's not a big deal, just one weekend afternoon of time and a near-meaningless dollar amount.

Given that -currently-, I don't have anything setup that would be fatal if a battery device dropped off for a day or two, I've been considering moving to the 'as needed' replacement cycle. (ETA: For clarity, the non-locks should all go longer than the annual cycle, likely between 18-24 months.)

I do understand that lithium batteries have a pretty steep tail on the discharge curve and a reported 50 (or whatever)% is really 10 (or whatever)%. I also have notifications setup for low batteries and get notifications if a device hasn't reported in regularly. (I think I have it at 12 hours for battery devices.)

I'm guessing that my (assumingly) relatively low device count plays a factor, as well. I have 17 devices that take various lithium batteries and 3 devices that take alkaline batteries. I also know there's no right or wrong answer. I was just curious how others approach this.

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I replace as needed. I use device activity as well to monitor all my battery devices.

I also use the Custom device note app to add when I last changed a battery so I can get an idea how often I am changing them. I use to think I was having to change them too often. I would think I just changed that battery, but now when I look it was 6 months ago.


I replace as needed except for my door lock. That gets batteries replaced when the battery level hits 60%.


I'll have to take a look at that app. (I think I remember some chatter about it.)

Currently, I just append the battery change date to the Device Name field.


I can then use the native search function of the Devices page to see what my battery situation is. Searching for '[' gives me all battery devices, and I can narrow it down further by date or battery type.


I think it's just a reality that battery level reporting is.... inaccurate.... So either approach is acceptable. My only recommendation would be if you take the approach of changing all batteries at once, perhaps adopt that for devices using rechargeable batteries, but non-rechargeable batteries, where possible, change those when you detect, in some way, a change in communications....


Agree that battery reporting for most devices is essentially useless (unless using a rechargeable, lithium-ion battery like in a laptop, tablet or mobile phone).

So I use “last activity” notifications to clue me into a device that has died, and change the batteries when that occurs.

The only devices I used to change batteries on a schedule were smoke detectors, because of the much more important implications of a device dying without realizing it (although how can you miss those middle-of-the-night low battery beeps, lol).

But now I have models with 10-year, sealed batteries, problem solved :slightly_smiling_face:.


Battery usage greatly depends on "foot traffic," quality of the driver and the health of the mesh. Devices that get a lot of traffic will need to be replaced more often, whereas those with low activity can go up to 2 years, maybe more. Also, a mesh that is not healthy will deplete batteries a lot faster. In my production, I replace the batteries as needed.


I have an outdoor air temp sensor for my Honeywell stat that I replace batts in every 2 years in the fall - it's just in a funky spot that's hard to access in deep winter or summer.

I replace the batts in the Yale lock on our most-used house door every fall as an abundance of caution.

Everything else is fly-to-fail.


As needed, unless it's a smoke detector where I do it once or twice a year as is often recommended (except I get lazy with the "smart" detectors sometimes that I guess are the scope of this question and wait until they start chirping--they are never my only detector in a room, just something I added, so I'm less concerned).

It may not surprise you to learn that I use Device Activity Check primarily to help me see when "as needed" ends up being.


One thing I have noticed since migrating to the C-8 is that batteries are draining much slower, and I think the battery life was generally pretty good before.

A big thank you for that handy little app. That’s what I’m doing as well.


Indeed, thank you for that. It's a key part of my notification method mentioned above. And it also has been invaluable in letting me know when one of my ZW15Rs has decided to go deaf-and-dumb again.

And while I'm handing out kudos, thanks to whomever also graciously wrote the 'Device Refresher' app, and to the HE team for including the ability to add battery notifications to the alarm functionality.

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+1 on using the Device Watchdog app. It's fantastic. (The Device Activity app is also great) It has allowed me to wait for a battery to either be below my threshold (20%) or fallen off of a dead battery and not reporting for 48hours.

Same, I thought I was replacing batteries way too often, but this has helped me realize I get 6months for most chatty devices (that have temp sensors) and a year+ for the rest.

The one exception is if we are about to go on an extended vacation, I will check the battery sensor of some items like water leak detectors and preemptively change them if it's been a while.

I run Device Activity Check.
I have emprically assessed each type of device and what the battery level really means, AKA about to die.
For the Aqara/Xiaomi stuff I have it report when Presense is lost.
I have 4 categories and get a notification in HE when any device gets to a threshold.

I use the device activity as well. I have no locks so if a water sensor is down for a day I consider it very low risk.

I do however have a sensor in the attic which is a pia to get to. So if I have to go up there and the old battery is more than 6 months, it gets changed.

because i have one house empty at all times.. when i leave there i replace all critical batteries whether needed or not . ie door locks.. temp sensors.. therms etc.

@JB_TX I use HSM to monitor all my batteries. Get a notification at 10% (was 20) and simply change them out... I also use Device Activity Check just in case as well.

I wait for the batteries to fail, then change them. Moved all that I could to rechargeable (CR2, CR123, AA & AAA).


You mean wait for the automation not to run when it should, then check the batteries? Sounds like me :joy:


Hehe, in some cases, yup. In others, I use Robert’s Activity Check app.

Looks like I need to pay more attention to it… I have redundancy for most of these, so it can take a bit of time until I start wondering why things aren’t working as well as they should…

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Me too. :joy: I've been getting a notification every evening for weeks but don't seem to care enough about those blinds (pretty much always closed this time of year) or basement temperature sensor (meh).

I'm thinking I should add an "every other day" option or something to avoid notification fatigue. But I guess that's why I added snooze...


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