Can I Use Lithium Batteries In A Smoke Alarm?
| Lithium 9V | Alkaline 9V | |
|---|---|---|
| Voltage | 9V | 9V |
| Diameter | Same size | Same size |
| Thickness | Same size | Same size |
| Capacity | ~1200mAh | ~550mAh |
| Chemistry | Lithium | Alkaline |
| Common uses | smoke alarms (recommended), carbon monoxide detectors, emergency devices | smoke alarms (adequate), guitar pedals, multimeters, general use |
Are they interchangeable?
Yes — interchangeableYes, and lithium is actually the better choice. Lithium 9V batteries last significantly longer than alkaline — typically 8-10 years vs 1-2 years. Most smoke alarm manufacturers now recommend lithium. Lithium batteries also perform more reliably in the temperature extremes found in lofts, garages and hallways.
The verdict
Use lithium 9V in smoke alarms whenever possible. The longer life means fewer low-battery chirps and better safety. Energizer Ultimate Lithium is the most common choice. Never use rechargeable batteries in smoke alarms.
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