i think it detect the voltage left by the battery
How does a rain detector works
If your smoke detector is still beeping after changing the battery, it could be due to dust or debris inside the detector, a faulty battery, or a malfunction in the detector itself. It's important to clean the detector, ensure the battery is properly installed, and if the issue persists, consider replacing the detector.
If the battery dies the smoke detector sill works, that the biggest advantage to using hard wire.
A battery-operated smoke detector is one which is not connected to your homes power supply.
Your smoke detector may still be beeping after replacing the battery with a new one due to issues such as a faulty battery connection, dust or debris inside the detector, or a malfunctioning detector that needs to be replaced.
The battery in a smoke detector should last a year (though the detector should be checked monthly). The detector works on "trickle" current that is always there. NiCads will lose more current than an alkaline battery from just sitting around - much more. Even a fully charged NiCad will usually not last a year in a smoke detector. Alkaline batteries will easily.
If your smoke detector is indicating a low battery, you should replace the battery immediately to ensure that the detector continues to function properly and provide early warning in case of a fire.
the battery
Your smoke detector battery is beeping to alert you that it needs to be replaced. This beeping sound is a signal that the battery is low and no longer able to power the smoke detector effectively. Replacing the battery promptly is important to ensure that the smoke detector continues to function properly and keep you safe in case of a fire.
Your smoke detector may still be beeping after the battery has been replaced due to a few reasons, such as a faulty battery, improper installation of the new battery, or dust or debris inside the detector. It's important to check these factors and ensure the detector is functioning properly for your safety.
If your smoke detector is still chirping after replacing the battery, it could be due to a few reasons such as a faulty battery, improper installation, or a malfunctioning detector. It is recommended to check the battery connection, ensure it is the correct type of battery, and if the issue persists, consider replacing the smoke detector itself.
If your smoke detector is beeping due to a low battery, you should replace the battery immediately to ensure the detector continues to function properly and keep your home safe from potential fires.