LPT: Only Use Lithium-Ion 9V Batteries in Smoke Detectors—Last 10 Years, No Late-Night Chirps Smoke detector batteries always seem to die in the middle of the night. After time and time again waking up in the middle of the night, finding a ladder, and replacing the battery, I knew there had to be a better way. A little research led me to 9V lithium-ion batteries, which can last up to 10 years in smoke detectors. I had no idea these even …