Myth vs. fact: Do batteries last longer in the refrigerator?

David Kender, USA TODAY

Know Your Stuff is a new column that unlocks the hidden secrets about the everyday products you own. 

If you were to peek inside my refrigerator, you might see a surprise next to the butter drawer: my batteries. I keep them there because, at some point in the foggy past, someone told me it was good idea, and I believed them.    

However, I've learned that gut instincts often fall apart in the face of actual facts. So I took my question to the experts and learned, yet again, that even the simple things we own can be surprisingly complex.  

Myth: Storing batteries in the refrigerator prolongs their life. 

Fact: It's partially true, but you're better off not doing it. 

In order to understand why, it's helpful to have some insight into how a battery works. To keep things simple, we'll limit ourselves to common AA and AAA batteries – not smartphone or laptop batteries.   

To get technical for just one moment, batteries release energy because of a chemical reaction between two or more compounds stored inside. Electrons flow out of the one terminal, through whatever device they're powering, and back into the other terminal.  

But even when they're not plugged in, those electrons can sneak invisibly out of the battery, draining their capacity through a process called self-discharge.  

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It's easy to see how common wisdom would point towards the refrigerator as a solution: If you can slow down the chemical reaction, you should be able to store batteries longer without losing any juice.  

So, should you? The answer from battery makers is a uniform and unequivocal.  

"That's a long-held myth, and the answer is no," says Tom Van Voy of Panasonic Energy Corp. of America. 

All the major brands recommend a clean, dry, room-temperature environment.

When stored properly, the discharge rate of a single-use alkaline battery, the most common type in the U.S., is negligible – only about 3% per year. Single-use lithium batteries lose even less.  

If you've been storing batteries in the refrigerator like me, don't kick yourself too hard. As it turns out, there's good explanation for why the myth exists.

Rechargeable batteries then and now 

Rechargeable batteries are likely the main reason so many people store batteries in the refrigerator. Up until a decade ago, the customer experience was pretty terrible and refrigerators were a stopgap measure. 

NiCd (nickel-cadmium) and NiMH (nickel-metal hydride) – the most commonly used rechargeable batteries – could lose as much as 20%-30% of their capacity per month. A few months on the shelves and they were effectively dead and in need of a full recharge. 

At that time, storing these types of rechargeable batteries in the refrigerator, or even the freezer, was recommended by some as a way of slowing such a rapid loss.  

Fortunately, there have been significant improvements in rechargeable batteries. Reviewed's current top recommendation for rechargeable batteries, Panasonic Eneloop Pro, can maintain 85% of their full charge for up to a year at a time – no fridge required.   

When your room's temperature isn't "room temperature" 

While refrigeration is a no-no, temperature still has a big impact on a battery's shelf life. 

When battery makers recommend "room temperature," they generally mean between 68-78°F. Depending on your location, though, your house may get a lot warmer than that.  And the hotter it gets, the faster your batteries lose their charge. Stored in a hot garage or closet, those batteries could drain themselves out two- to four-times faster.   

Keeping them dry 

Yet another reason experts recommend not keeping batteries in the fridge is condensation.  

"Humidity can impact batteries as a whole, says Van Voy, "and that's why we recommend a dry storage environment. You build up condensation in a refrigerator."  

If you insist on keeping your batteries in fridge, at least put them in an airtight container where water vapor can't get at them.   

But consider me reformed. You'll find my batteries in the drawer from now on.    

David Kender is the editor in chief of Reviewed, a product review website and part of the USA TODAY Network. If you have a question about how your stuff works, or just want to know what to buy, email him at request@reviewed.com.  

This article originally appeared on USA TODAY: Storing batteries in the refrigerator: Myth versus fact.