During my army days, I was stationed in Alaska. Winters were pretty cold (imagine 57 below), and during trips to the field, shaving with cold water wasn’t an appealing option. The alternative was to bring a battery-powered razor with spare batteries to the field. In the cold mornings, I’d find that my battery-powered razor wouldn’t run at full speed until after “warming up” the batteries with my hands. The lesson learned from this experience is that in cold conditions, battery voltages will drop in cold climates.

Many household smoke detectors have a low battery alarm. This alarm can be a simple “chirp” every minute on the minute. Over time, a battery will loose some of its charge. After enough charge is lost, the “chirp” notice will start taking place. When do you believe is the most common time for a fire alarm to start “chirping?”

Many homes are air conditioned throughout the day. The air conditioner is able to maintain a steady, cool climate in the home. During nighttime, the sun is no longer heating the shell of the house. Temperatures can drop lower than the cool setting on the air conditioner. The end result is that the coolest temperatures of the home is somewhere between 3am and 5am. During this time, the voltage in the smoke detector batteries can reach their lowest voltage. If low enough, your fire alarm battery alarm can wake you hours before your alarm clock.

Everyone has a choice to make. You can either replace your fire alarm batteries every year on a specific date (New Year’s is a popular option), or you can wait for your smoke detector to “tell you” that it’s time to change the battery. Just remember that you can always smash the alarm clock to shut it down. Some smoke detectors are mounted high on the wall, and some will still chirp after ripping it off the wall and hurling it down the hallway, if the circuit is still intact.

Pleasant dreams!

-M