9 Volt Battery Safety Alert

Estimated reading time: 2 minutes, 59 seconds

I saw a heartfelt plea from a gentleman on the internet that had a 9 volt battery cause a serious house fire. Part of his concern is that he felt very responsible because he was ignorant of the danger and asked that I pass this information along.

I’m doing my duty to pass on the warning.

The story is that when he changed out his smoke detector batteries once a year at daylight savings, just like the fire department recommends, he put the old ones in a bag and left them in the garage on a shelf. Later he inadvertently bumped the bag and in doing so, jumped the contacts together which caused a heat reaction that ignited some nearby clothing. Ultimately a lot of property damage occurred but thankfully, there was no loss of life in this case.

In my estimation 9 volt batteries last anywhere from 2-10 years, hell the smoke detectors themselves should be changed out every 8-10 years. Smoke detectors, like CO (Carbon Monoxide) detectors save lives.

They all alert folks in enough time to either extinguish a small fire or get out in time to save lives. Most new ones are designed to be electrically energized with a battery backup.  However, many homes are still only equipped with the battery only units.

9 Volt Survival Tool

Fire Starter

Fire Starter

9 volt batteries have long been used as a survival tool. It only takes a second to start steel wool on fire, just to give you an idea of how much potential energy is stored inside of them.

Inherent problems

No one wants to hear the chirping or experience a false alarm (which always happens in the middle of the night.) Yet, I’m thankful that they do because the assumption is that, if they are silent, then they are armed and fully functional. A little known bit of trivia is that they start chirping when they still have 2/3rds of their strength left.

Building codes now mandate that all of the installed smoke and CO detectors are electrically tied together so when one goes off, then they all do. (Exceptions exist when remodeling, they are rare and likely hardship generated)

When to Change Them Out

Here is my recommendation: Disclaimer (This is just how I do it) Rather than switching batteries annually, test the unit by depressing the test button with the handle of a broom or some spray some synthetic smoke to see if it is working every year. If it doesn’t work, then do some trouble shooting or replace the darn thing. It is a small investment in the big picture.

Using a simple battery testing tool will also help in making a trouble shooting diagnosis. I’ll bet you’ll stop throwing away perfectly functional strong batteries.

Storing 9 Volt Batteries

Disposing of good batteries is silly. If you do have to dispose of a dead one, just throw it away. But if you are  saving one that has been chirping, or storing 9 volt batteries for any reason, put a piece of tape over the contacts to render the strong batteries super safe.

In the words of one of my hero’s, Sargent Phil Esterhaus of the Hill Street Blues, “Lets roll, and be careful out there!”

For more information than you would ever want to know about these batteries click here

Your comments are welcome. To ask questions or get more information about remodeling, click here to email me directly, or call 208-947-7261


  • howard olivier says:

    Thanks for significantly reducing the waste of good batteries – this is the very best kind of ‘green’ advice.

    I like knowing about the survival tool aspect! thanks for the solid tip on covering the contacts with Electrical tape, for full safety in storage.

    • Joe Levitch says:

      I hadn’t dawned on me that this was a “green” thing to do, but you are right! I’m glad you appreciated the safety tip. This one has a pretty serious down side if ignored.

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