You’re supposed to replace the smoke detectors every 10 years because they lose sensitivity. In my experience, 9v alkalines in the AC powered models last nearly that long. I assume it’s just the shelf life of the battery.
73 Josh W6XU Sent from my mobile device > On Oct 5, 2021, at 1:22 PM, jerry <[email protected]> wrote: > > I have a related questions about batteries discharging... Not really about > ham radio, all please feel free > to delete... > > We have a *lot* of smoke detectors. They are the kind that runs off the AC, > but each one has a backup > battery. The other day, one started beeping...and beeping...and beeping. > That momentary beep that says > "change my battery!". > > Amazon couldn't get me batteries the same day. And the beeping makes it hard > to sleep. So I went to the garage > and got one of a set of rechargeable lithium 9V > rectangulars that I had bought for test equipment - DMMs and such. > > The old battery in the smoke detector was 7.88V. The lithium - 9.4. > Installed it...and no beeps! > > It's tempting to just load all the detectors with lithiums. The alkalines > last a couple years. Maybe a fully-charged > lithium would last as long... and then you recharge it? If so, they'd be a > good deal. If OTOH they only last a couple months, > that's NOT a good deal, because I'd have to get out the ladder etc every time. > > ?? > - Jerry KF6VB ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [email protected]
