I have an alarm clock with an LED display that has a 9v battery back-up. If I leave the battery plugged in will that use up battery power?

The alarm clock offers a 9v battery back-up. If I lose power, the 9v battery will keep the alarm clock running so that it wakes me up on time. If I leave the battery installed, will it automatically use battery power, whether the alarm clock is plugged in or not? Or would it only use battery power when I lose electricity? Intuitively, it would seem that it wouldn't use battery if the alarm clock remains plugged in, but is that wrong?

5 Answers

  • Anonymous
    6 months ago

    If the battery is in the clock and the clock is in the wall outlet plugged the battery would remain inert up until the clock loses power, you unplug the clock from the wall outlet.

    Even still it is guaranteed to probably work a few hours in keeping time because when you plug the clock back into the wall outlet, it might loose some minutes or be off some.

  • 6 months ago

    The battery is there to keep Approximate time during a power outage

    (usually it is pretty far off in terms of minutes) so that,

    IF the power comes back on before your alarm is supposed to sound,

    you will be awakened at something vaguely resembling the correct time.

    The alarm Will Not sound if the power is still off.

    In order to keep the backup function reliable,

    the battery should be replaced every six months whether it is run down or not.

    So far as I'm concerned, it's a waste of money

    and I prefer a wind-up alarm so it can't be affected by a power outage.

    I have a nice Westclox La Salle (61-J) from the 1930s

    with a pleasant but effective bell inside it.

    That is my favourite clock for important wake-ups.

  • 6 months ago

    If it is well designed, it will not use battery power unless there is a line power failure. The battery will run down at the same rate as it would if it was in the desk drawer - i.e. its shelf life.

  • 6 months ago

    yeah why not yes

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  • 6 months ago

    I have one of these.

    The only purpose of the 9v battery is to keep time while the power is out. The alarm will not go off when the power is out.

    And even if you never lose power, the battery will run down.

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