Smoke Detector Batteries Cannot Be Rechargeable
Our smoke detectors are always beeping about low batteries. It drives me nuts. They beep intermittently so it’s hard to locate the beeping detector until it’s 2 am and I can’t get back to sleep because a mysterious smoke detector somewhere is beeping.
I felt like I was replacing these batteries so frequently that I started looking at rechargeable 9V batteries. We don’t have all rechargeable batteries–some things, like toys, we might not replace and then forget about the battery and lose it–but I am trying to get better about using rechargeable ones when possible. As I was about to buy a whole set of batteries for all our smoke detectors, I read a review that noted that rechargeable batteries are not approved for smoke detectors.
Because rechargeable batteries discharge very quickly at the end of their life, they could potentially go from working to dead without beeping enough that someone could hear them. The other concern is that their charge generally does not last as long as disposable ones, and because of the importance of a long life span in a smoke detector, they are considered unacceptable.
I was thankful to have figured this out before I bought a whole set of 9V batteries I would probably not use very much (we use AA the most, by far), but it didn’t solve my beeping smoke-detector problems. So I devised a new system: I would change all the batteries on the same regular schedule, on New Year’s Day and the Fourth of July (everything says to replace smoke detector batteries every 6 months).
Interestingly, it is now March and I have had to replace all the batteries again already, because one by one they all started beeping within a two week period lately. Obviously, these batteries have not lasted six months. What does that mean? 1) I am not crazy–I WAS replacing the batteries all the time and 2) Our batteries are lousy! They should have lasted at least three times as long as they did.
Sometimes you get what you pay for; for the sake of not buying more batteries than necessary, spring for the nice name brand ones, they really are better.


