DIY Doctor UK DIY Forums

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?

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

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.