It’s time to check your smoke detectors! Change your battery when you move time back on Sunday, November 4, 2018. Almost 25% of smoke alarm failures were due to dead batteries. Smoke Detectors SAVE LIVES! FREE battery operated smoke detectors are available for residents living within the City Limits. If you need help installing or checking your battery home smoke detectors, call the Smoke Detector Hotline at 512.393.8484.