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Topic: Smoke Detector  (Read 4040 times)

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Offline Enthalpy

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Smoke Detector
« on: September 16, 2023, 07:51:53 PM »
Hi everyone and everybody!

My home's smoke detector contains an Li-SOCl2 battery. That's the most dangerous choice: not only does it burst and catch fire if flames reach it. This combination is also more prone to light if crushed. Worse: it releases badly toxic gases if burning.

A company installs and replaces the detectors. They, and the inhabitants, complain about the battery's duration. This explains the Li-SOCl2 with more capacity in the same size. Probably a late drop-in change, when the detector was already designed. But I hate this unreasonable risk.

Designing a smoke detector isn't that difficult! Send collimated light pulses in one direction, detect in an other the light diffused by smoke particles, if too strong sound the alarm. Any decent duo of optics+electronics engineers should achieve it, within correct power consumption.

Most competitors achieve longer operation from an alkaline battery. An even better choice would be a Zn-air battery: safe, powerful enough, longer operation life than most Li batteries.

I opened hence destroyed the detector because it started to yell repeatedly with no reason. Its battery isn't even replaceable anyway. On the same day, my computer's Cpu drew too much power as indicated by the fan's speed, and my cell phone's battery went empty far too early. This is consistent with an electromagnetic weapon on that particular day. It's no general explanation for the abnormal consumption of this design.

Marc Schaefer, aka Enthalpy

Offline Enthalpy

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Re: Smoke Detector
« Reply #1 on: September 20, 2023, 05:30:06 AM »
The smoke detector contains not one SOCl2 battery, but TWO in parallel, not even with diodes. When I was young, this was taboo. Obviously,  someone tried to tinker the battery life problem. It costs a fortune and isn't solved.

The circuit is essentially a microcontroller with ADC. What a fuss to compare a number of optical pulses with a threshold!

So the general explanation is simple: incompetent electrical engineer. The customers should seek a different design by an other company. Competitor smoke detectors use one replaceable alkaline battery for years.

Offline Absence

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Re: Smoke Detector
« Reply #2 on: November 09, 2023, 04:03:45 AM »
Were you able to find out what the problem is with energy consumption?

Offline wildfyr

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Re: Smoke Detector
« Reply #3 on: November 10, 2023, 10:21:43 PM »
Thionyl chloride is found in homes??!?!?!!!?!??!

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