![]() ![]() I plan to change my device handler for the First Alert alarms to reinterpret the battery status message range so SmartThing’s Device Health will warn me with enough time to avoid the midnight chirping incidents. I think the behavior for new alkaline batteries is predictable with a nice linear slope. My multi-meter read both batteries at just above 1.3 Volts 77% of 1.5V would have been 1.15V under load. Both were running on the original Duracell AA alkaline batteries included in the package. So the resolution on the First Alert alarms is 1% decrements. Both of the previous battery levels were 78%, and had been at 78% for at least one week. Both started chirping immediately after reporting a battery level that showed up in my SmartThings logs as 77%. Both of my incidents involved First Alert Z-Wave alarms manufactured in Q’3 2015 one detects smoke, the other also detects CO. I’m going to put the same batteries in a second device and see if it also reports 1% though I’m not sure that information will help contribute to this problem.ġ9 minutes agoĝEVICE batteryđ Den Smoke CO Alarm battery is low! trueġ hour agoĝEVICE alarmState clear Den Smoke CO Alarm test cleared trueġ hour agoĝEVICE carbonMonoxide clear Den Smoke CO Alarm carbon monoxide is clear trueġ hour agoĝEVICE smoke clear Den Smoke CO Alarm test cleared trueġ hour agoĝEVICE alarmState tested Den Smoke CO Alarm was tested trueġ hour agoĝEVICE carbonMonoxide tested Den Smoke CO Alarm was tested trueġ hour agoĝEVICE smoke tested Den Smoke CO Alarm was tested trueġ hour agoĝEVICE Den Smoke CO Alarm code 13 is 0 trueĤ hours agoĝEVICE batteryė7 Den Smoke CO Alarm battery is 77% trueĥ hours agoĝEVICE batteryė8 Den Smoke CO Alarm battery is 78% trueĢ days agoĝEVICE batteryė8 Den Smoke CO Alarm battery is 78% trueĤ days agoĝEVICE batteryė9 Den Smoke CO Alarm battery is 79% trueĦ days agoĝEVICE batteryė9 Den Smoke CO Alarm battery is 79% trueĪlthough with duty-cycled devices that are designed for low power operation, the voltage under test shouldn’t be too far away from open circuit voltage, and irregardless, the behavior with my alarms is repeatable, and that is why I posted to provide two data points. In other words, I could say the batteries are pretty close to the 77% reported, but I also could understand if the device thinks that 66% is too low and warrants chirping, but how can it report 77% one moment, and 1% after just inserting the batteries the next moment? I understand that “low voltage conditions” are necessarily considered linear to “battery capacity”, so (1v+1v)/(1.5v+1.5v) = 66% normal voltage does not necessarily correspond to 66% battery capacity. ![]() Checking with a multimeter, the batteries have about 1v each. Of course, if the device were a little smarter, then it should offer an additional special “low battery alert” message that corresponds exactly with the start of chirping (or perhaps at a level that is typical of 24 hours before chirping?.), but absent that, I wonder what’s happening here. The device promptly reported battery level as 1%! ![]() I took out the batteries and re-inserted. In other words: *there was apparently sufficient battery and connectivity to a rather more than sufficient battery capacity at 8:15am& … I’m not sure what time the chirping started though!). So I had one of my First Alert Z-Wave ZCOMBO Smoke & CO Detectors go into the dreaded (though not as bad as fire! ) “low battery chirping mode” this morning.Įxactly one of the situations I was hoping to avoid by using a “smart” device.Īccording to the “Recently” tab, at 8:15am the battery was reported to be 77% (history shows a drop from 79% to 78% over the last 6 days … seems perfectly normal).
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