But since 9V became the standard for smoke detectors, battery companies have made better 9V smoke detector batteries. The good ones are based on Lithium technology, which means you get a battery that lasts 10+ years in operation -- in some cases, the practical life of the detector itself. read more
—William P. Bivins, Greenville, NC. A. Lithium 9Vs aren’t recommended for smoke detectors unless you follow a strict battery replacement schedule. read more