First Alert Smoke & CO: Battery level report very wrong...?! CHIRP! CHIRP!

Wouldn’t that be nice? Can’t really say what’s going on in their firmware though.

I ran into this problem just today, as the first of my units started chirping at 77% battery. I wouldn’t hold my breath for a firmware fix for these, so I figured I’d just re-calibrate their existing battery report to the approximate 77-100 range that it seems like these actually work in. I grabbed DH code off Github from the link above and changed line 190 to this:

map.value = (int) ((cmd.batteryLevel - 77) * 4.347826087)

That definitely won’t help with accuracy or the frequency of reports, but at least the values it reports would make more sense since they’ll be scaled appropriately.


How often do these First Alert combo units report battery level, and is there any way to force it? Yesterday I tested one of my units and it immediately went from reading 88% to 1% and started chirping. I replaced the batteries, and tested it, but it still hasn’t reported the new battery level.

If you read the posts above, you’ll see that the “1%“ is what smartthings uses when it receives a special “low battery!“ Message from the device, but the device might send that message at anywhere the manufacturer thought was significant, even 70%.

All smoke detectors, regardless of brand, try to use as little battery as possible to stay ready for a real emergency. And since even sending a battery report uses up battery life, they tend to report much less frequently than many other device classes.

I don’t know specifically for this model, but most of the battery powered smoke alarms I’ve looked at only report the battery level once a week. And they do send a “low battery!“ message much sooner than most other devices as well, typically quite a bit above 50% reserve.

So… The dropping from 77% to 1% probably is an artifact of the way smartthings handles the “low battery!” Message. It might well just have dropped from 77% to 70%, for example.

And the reporting frequency may well be just once a week, that is typical for smoke detectors. You could contact the manufacturer to be sure.

Both of mine are above 80%, however I have moved them on Edge driver, and there is no battery capability in history. I have them on this batteries for more than a year.

Added this just to see if it’s monitored by SmartThings

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