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Thread ID: 150597	2022-04-16 07:05:00	family shield mini smoke alarm	tweak'e (69)	Press F1

Post ID	Timestamp	Content	User
1485548	2022-04-16 07:05:00	i have a couple of family shield mini smoke alarms and one of them started randomly beeping in the early mornings. we have just got some cooler weather. i found a few reviews that said they are poor and warranty not worth the paper its on. all the info seams to say low battery. so today it started false triggering and i could find which one it was, and then pull it to bits. these are photo electric so no radioactive stuff to worry about. the main thing i was looking at was the battery. open voltage seamed ok, low but not to low. but that also depends on what voltage the chip needs. this has a varta brand battery, fairly good brand. these have a storage life of 10 years. but the interesting thing is the date code. so i found a data sheet that explains the codes. this battery was made in may 2006, the smoke alarm was made in oct 2017, and i bought it in 2019. so the battery is 16 years old already and its meant to last for another 5 years. no wonder these have a reputation of failing, they are made with end of life batteries.	tweak'e (69)
1485549	2022-04-18 04:08:00	update. possibly i have date code wrong. however i did find a similar chip and wiring diagram to it. a couple of interesting things is that it actually runs on about 9v. the 3v is upconverted to 9v but only in a pulse. to save power it operates it once every 10 seconds or so. but the pulse actually draws quite a bit for a very short length of time. this makes it rather reliant on having a good battery. its noted in the tech sheet that it should have a very low resistance to the battery. however this design does it poorly. it runs the power over two daughter boards, so there is a lot of extra connections. any poor join can make the voltage drop to much. also i notice that there is a lot of poorly cleaned flux on this, mostly where they soldered the daughter boards on. that makes me wonder if humidity is playing a role in the failures. a lot of these fluxes will soak up moisture which could cause tracking across pins. especially as its got some on the chip legs. that might explain the weird beeps it was making. as it wasn't a full alarm and wasn't the typical flat battery beep. it could simply be poor quality manufacture rather than battery failure.	tweak'e (69)
1485550	2022-04-18 05:04:00	Why not connect suitable new batteries and see how it goes, that will tell you if it was manufacturing defect or sad battery. Up-converting from two AA or AAA is a much better idea than using those 9volt rectangular packs.	zqwerty (97)
1485551	2022-04-18 09:13:00	Why not connect suitable new batteries and see how it goes, that will tell you if it was manufacturing defect or sad battery. Up-converting from two AA or AAA is a much better idea than using those 9volt rectangular packs. because its such a random failure, extremely annoying and possibly dangerous. it might take months if not a year for it to fault again. its not just worth keeping. once i get some replacements i might go test the other one of this make.	tweak'e (69)
1485552	2022-04-18 09:35:00	I have three of the radioactive type in my place (one in the kitchen, one in the passageway and one in the garage). I reduced the number down to one because of random false alarms, lo-battery beeping/chirping on colder mornings and at best they only last about one year before battery, (the dreaded 9v type) needs to be replaced. A not very good product used to distribute Americium waste radioactive material, from nuclear reactors, around the world. The most annoying part is that my dog hates the sound and will not come back in the house for ages after the thing starts beeping for whatever reason, 3 of them was too many to manage.	zqwerty (97)
1485553	2022-04-18 09:41:00	I have three of the radioactive type in my place (one in the kitchen, one in the passageway and one in the garage). I reduced the number down to one because of random false alarms, lo-battery beeping/chirping on colder mornings and at best they only last about one year before battery, (the dreaded 9v type) needs to be replaced. A not very good product used to distribute Americium waste radioactive material, from nuclear reactors, around the world. thats why i went to the 10 year battery models. the cavius brand i have no issues with, its just these others. the cost of replacing 9v batteries is more than the cheap smoke alarms. having one per room is recommended. especially bedroom. the photo electric ones are meant to be better for smoldering fires. with the amount of electrical gear plugged in, its a more common type of fire. actually a guy at work had it recently when the end of the cell phone charger cable started melting and smoking.	tweak'e (69)
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