Have you ever wondered about replacing a battery in the battery-operated smoke alarm or detector? Hi, I'm Chief Joe Bruni. Changing the battery on a battery-operated smoke alarm or smoke detector is relatively a simple procedure and process. Most smoke alarms that are battery operated operate off of a simple nine volt battery. And many have some type of a mounting plate such as this smoke alarm. The mounting plate stays to the wall as a simple twist of the smoke alarm will remove it from the mounting plate. The smoke alarm battery should be replaced approximately every six months and we recommend every time you change your clock, you change your battery. If the smoke alarm starts to emit a chirping sound approximately every minute to two minutes, it's simply telling you the battery is low and needs to be replaced. The battery can be removed by simply pulling on the small ribbon that will release the battery from, from the battery holder or carriage. Sometimes a small plastic lever will expose itself and that's simply a lever that is for safety purposes so the smoke alarm cannot be disabled and put back together on the mounting surface without the battery being in place. Check the terminals and the contacts on both the battery and in the smoke alarm for corrosion at the time of battery replacement. If corrosion is noted, clean the surface of the contacts and replace with a fresh clean battery. If the corrosion has caused damaged to the smoke alarm, replace the smoke alarm itself. They're relatively inexpensive. Inside the carriage will be marked a positive and negative sign for polarity of the battery. The positive is the smaller terminal that is round in shape; the smaller oblong or octagon shaped terminal is the negative one. Line up those properly with the polarity, a positive and negative and make sure the ribbon goes under the battery. Snap the battery in place and simply mount the smoke alarm back onto the mounting hardware surface and reinstall the smoke alarm. I'm Cheif Joe Bruni, stay safe.