I would get the brand name off the cover and google it...there is usually an owner's manual on line that will tell you how to get the cover off without breaking it! Or phone the manufacturer and ask. There are so many different ways these covers come off!
There is a door in the side that when depressed opens. The whole cover does not come off. When you get the door open (not easy), slide out the old battery and insert a fresh alkaline one, close door and test it. Mine are sensitive and don't work with all batteries.Some are fresh and still chirp because they aren't compatible with my brand smoke detector. Get on a ladder so you are eye level with the detector to see the door that needs to be opened. Jill
Removing smoke detector covers can be difficult. Usually a tab has to be depressed. Try usinf a small flat blade screwdriver. Replace the battery with an ALKALINE battery. Ordinary batteries may be fully charged but will not work in a smoke detector. Good luck!
Getting the lid off can be a pain. There's usually a little tab that's supposed to give to pressure. Just keep trying; my son finally got ours off after I was sure it wouldn't.
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