• Flying Squid@lemmy.world
      link
      fedilink
      English
      arrow-up
      3
      ·
      2 years ago

      The smoke detectors in my house are hooked up to the main power, but they still take a battery and beep when the battery is dead. I thought the battery was backup, but they die after about 2 years, so it can’t be backup, it must be used for something.

    • Blackmist@feddit.uk
      link
      fedilink
      English
      arrow-up
      1
      ·
      2 years ago

      Even the 9V ones didn’t last forever.

      I found that out one very exciting morning, when it decided to sing me the song of its people. If you’ve never stumbled down the stairs at 4am looking for a fire with your bollocks flapping about, I heartily recommend it.