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[saki]

Hope this is the correct forum for this question. I have two wired smoke detectors in upper and lower hall. They have the usual 9v battery back-up. Due to the recent storm our power has been switched off several times for many hours. The smoke dtector in lower hall began chiruping after two hours which I assumed meant the battery was low. The detector in upper hall was silent. When the power was restored I expected the low battery warning would continue but to my surprise it fell silent immediately the power came back on. This happened at every power off/on sequence. I'm going to replace the battery anyway but confused as to why the chiruping stops when power is restored. Am I misinterpreting the situation?

[Mr White]

It sounds like it has a rechargeable battery that is indeed going low, but when the mains are restored it charges the battery so it is no longer low. But without more information (Such as Make/model how often it chirps, what colour "lights" are on, how many times do they flash, how often do they flash) it is not possible to be definitive

[saki]

Thanks for your reply. The battery is a standard 9v so not rechargeable. Unfortunately there is no manufacturer's name on the detector and I cannot find the manual. I'll just replace the battery once the power cuts are over.