Comment by Someone1234
Comment by Someone1234 15 hours ago
Most of those smoke detectors are old and already passed their 10-year-lifespan. People keep putting 9-volt batteries in them, but they shouldn't.
If you go look at modern smoke detectors, many-to-most, now have a non-replaceable battery for exactly that reason.
I didn't have to look far to replace my combo CO/Smoke detector or do a ton of hard searching to find one that just took a 9-volt. The first two results on Amazon US for "smoke detector" take 9-volts.