Households are being told to stop storing batteries in the fridge because it can actually damage them, rather than make them last longer. An old wives' tale has circulated for many years suggesting that putting AA or AAA batteries in the fridge can make them last longer when not in use.
This is not actually untrue, but the technology has since moved on, except the advice has stuck. So many people are now storing their batteries in the cold when it isn't helping anything, and in fact could even be dangerous.
Why the advice is outdated
According to BatteryGuy.com, the difference is due to a change of battery technology from the old zinc-carbon to modern alkaline. Zinc-carbon batteries powered almost all portable devices for nearly 50 years after their invention in the late 1800s and do indeed last longer if stored at between 40 to 50°F (5 and 10°C).
After four years at this temperature, a zinc-carbon battery will still maintain 80% of its capacity compared to 65% for a unit stored at 70°F (21°C). Zinc-carbon batteries are disposable, once they are flat they are of no use, and so the practice of keeping batteries that were not in use in the fridge became widespread.
Modern batteries do not benefit
But alkaline batteries were invented in the 1950s and these do not benefit from being kept cold. Alkaline shows almost no improvement in self-discharge when chilled or frozen. However, for many people a battery is just a battery and so the practice of chilled storage was often continued.
Although modern, post-1990 alkaline batteries do show some benefit from being kept cooler, manufacturers no longer recommend fridge temperatures.
What manufacturers say
Duracell, on its website, has an FAQ which asks: “Should I store my batteries in the refrigerator or freezer?” Its answer is: “We recommend storing batteries at room temperature in a dry environment. Extreme heat or cold reduces battery performance. You’ll want to avoid putting battery-powered devices in very warm places. In addition, refrigeration is not necessary or recommended.”
Energizer, in its guide on storing batteries, simply recommends avoiding storing in excessive heat, but does not suggest refrigeration. It says: “Storage: Store in a cool, well ventilated area. Elevated temperatures can result in shortened battery life.”
