Hi - Installed six First Alert Zcombo smoke/CO sensors couple of months ago. One of them started chirping this morning. Checking the status of the battery shows that it is at 92%. I was expecting a notification when battery is below 50% but since it at 92% there are no notifications but it started chirping. There are two others sensors that are at 92% with no chirp. Does anybody else has such a experience with First Alert? Checked the battery voltage. They are at 1.44V and 1.1V. 1.1V looks low.
So is it 1 chirp or multiple?
| Chirp Pattern | This means… |
|---|---|
| The horn chirps 1x per minute. | Low battery warning. |
| The horn sounds 3 chirps every minute. | Malfunction warning. CO alarm needs to be replaced. |
| The horn sounds 5 chirps every minute. | End of life signal. CO alarm needs to be replaced. |
I've had the old (non-ZWave Plus) version of these for a few years; though they have adequate battery life (probably approaching a year or more) their batteries require replacement before indicating 80% or they will chirp.
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Six months ago I replaced all my smoke detectors because they had reached end-of-life. I also replaced the batteries with lithium batteries. After 6 months the device report 100% battery level and the battery measures at 1.74 volts. I did this to reduce the replace battery chirp.
1.1v? I have 6 Z-combos, anything <1.3 will get you a chirp. I always measure my batteries when exhausted, usually they are 1.3. I keep the batteries around as they're still good for my wife's crappy fake candles and random holiday singing elfs. I'm guessing as it's a life safety device, they program it very conservatively with regard to battery life.
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I am running 4 of these smoke/CO sensors and my magic number has also been 80%. I am on borrowed time once I reach that point.
The difference in battery voltages is the only part that concerns me. One was in bad shape - either from the factory or an unintentional discharge event. If a fresh pair behave well, then I would simply call it a fluke and move on.
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One chirp every 40s. Replaced the battery and it is behaving now. I still see the new battery at 92%. Will check it again at night.
Does battery attribute really works in z- wave world? So far it has never worked on 10s of sensors that I own. I attend them when they go belly up with no notification.
Let me know if you guys have this attribute working reliably. May be I am missing something.
Accurate battery reporting is one of the long ongoing discussions around here, but the general consensus looks to be that it is not achievable with today's devices and standards.
You have a point. We can do that easily in modern cell phones using something called coulomb counting. Here is a good article on it and a regulator that does it. At $4, it may be cost prohibitive for $10 to $20 z-wave devices.
Ring devices has the same issue. I got around 50 of those, none of them report bad battery and just die on you.
Ha Smarthings can do it perfectly fine. It's been telling me my motion sensor is at 15 % and it's time to change the battery (for NINE MONTHS)- it's almost accurate! 
I just looked at my one Zcombo. It's at 88% after almost exactly a year. It's in the garage so I might not hear the chirp. Do they send some kind of message out as well? Something that Hubitat recognizes?
Maybe if you use @jtp10181 ’s driver. I’ve been using it on my zcombo detectors for a while, but mostly to detect the eol chirp when it happens (2 of my detectors are getting up there in years).
I don't think it will pick it up. I just checked the list of system events and none of them are about low battery.
Technically the device should be sending a battery level of 0xFF (255) which indicates low battery. That would cause the driver to report 1% battery and a WARN log saying low battery reported. But it is obviously not doing that so....
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