Battery Backup on Wired Smoke Detectors


Old 11-07-19, 01:15 PM
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Battery Backup on Wired Smoke Detectors

So I just finished the annual ritual of replacing the 9V batteries in my 11 wired smoke detectors. I thought I would post here and see if anyone had any other ideas or thoughts as it seems like changing this is a waste of good batteries.

Know that a key priority for me is to never have to hunt down a chirping smoke at 3AM. We have done that a few times before and it is a horrible experience. So I have to admit that changing them annually has caused us to never have to deal with a 3AM chirping smoke.

But this year I decided to check the voltages of these batteries and they were all at 9.3V with expiration date 2023. Do they really need to be changed? It just seems like a waste especially since these are not cheap (at least Duracell's are not cheap).

One thing I did is shop around and found a sale at Amazon on Energizer Industrial so I have those in now as I type this.

And of course I can re-purpose these batteries but it turns out that virtually nothing anymore uses 9V's! I've even started looking for craft projects and science projects that could use 30 or 40 of these batteries!

So I am just asking if anyone has any out-of-the-box thoughts on this or "fresh eyes ideas" on whether or not my annual ritual is necessary and/or can be improved or made more efficient.
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Old 11-07-19, 02:46 PM
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Many of my customers wait until the first chirp to call me to replace them all. I change my own every other year. I wouldn't wait longer than that. Routine battery replacement is a life safety choice. Can't really put a price on that.
Old 11-07-19, 04:00 PM
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Thank you PJmax. Yes I was thinking of skipping a year or waiting until the first chirp and then replace all ... until I read that you want fresh batteries so if they do alarm, the alarm is LOUD and SUSTAINED for as long as possible. But maybe every other year could work.

Old 11-08-19, 03:18 PM
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The newer, lithium batteries, you can go a much longer time. I wait for the first low battery chirp, myself. I plan to upgrade to lithium battery photo-electric models, when I decide that my existing ones are old enough (which will be this spring); which will make my battery life span in the 4-5 year span.
Old 11-09-19, 05:30 AM
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Presumeably you are using alkaline batteries.
One characteristic of this type is that the discharge curve is very steep.
The will produce full voltage for about 90% of the batteries life then drop to zero in an extremely short amount of time.
You will want to replace them when they are at full voltage and any you save will likely be useless.

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