Some household batteries may last slightly longer if stored in the refrigerator or freezer. Even when not being used, the internal components slowly corrode over time, and cool temperatures can slow down this process. The type of battery and how it is stored will greatly affect whether refrigeration is an efficient means of extending its shelf life, however. Rechargeable varieties get more benefit from the cooler temperatures than alkalines do. All types of batteries must be protected from moisture in the refrigerator, so they should be kept in a sealed container.
Refrigerating Alkaline Models
Since most manufacturers recommend storing batteries in a cool, dry location to last as long as possible, it may seem logical to keep alkaline models in the refrigerator. Most refrigerators maintain an average temperature of 40° Fahrenheit (approximately 4° Celsius) or lower, and the atmosphere inside is very low in humidity. This seems like an ideal storage environment, as the lower temperature reduces the power drain on the electrolyte fluid inside the battery, which acts as a medium for the flow of the electrical current. According to the results of several tests, storage at very cold temperatures will increase the shelf life, but only by a small amount. Alkaline models stored in a refrigerator can retain 93% of their power after five years, compared to 90% for non-refrigerated models stored in other cool, dry areas.
The downsides of refrigeration for alkaline varieties may outweigh the minor extension in their shelf life. Although a refrigerator has low humidity, batteries that are not sealed in an airtight container may be subject to contact with moisture from other items in the refrigerator, which can destroy the electrical circuit. Extremely cold temperatures can also corrode the contact points on either end of the battery, rendering them unusable. One of the biggest downsides is that the batteries must be returned to room temperature before they can be used, so they cannot simply be taken out of cold storage and put immediately into electronics.
Refrigerating Rechargeable Models
Rechargeable varieties, such as nickel-metal hydride (NiMh), can benefit greatly from cold storage when cared for properly. While rechargeable models offer many advantages over alkaline varieties, they suffer from a fairly short charge life, and may need to be charged every few days when stored at room temperature. Carefully stored in the refrigerator, a rechargeable battery can hold at a 90% charge for months at a time.
For best results, rechargeable batteries need to be kept in a sealed freezer bag inside an airtight container to reduce the risk of moisture damage or condensation. Any moisture can cause corrosion inside of the battery, making it unusable. Like alkaline models, rechargeables will need to be thawed before they can be used.
Other Ways to Extend Shelf Life
People who are concerned about getting the most use out of their batteries should consider investing in rechargeable models, which can be used dozens of times without replacing. This not only cuts down on the cost of supplies over time, but is also more environmentally friendly. Recharging the batteries before they are completely depleted can also extend their lifespan, as draining a battery fully usually causes it to wear down more quickly.
It is also best to use the right type of battery for specific electronics. Some devices, such as digital cameras, use up a lot of power quickly, and eat up regular alkaline varieties in just a few hours. Some batteries are built to withstand the increased power needs of high-drain electronics, so they should be used to reduce costs.
Batteries should be removed from electronic devices when they are not in use to extend their life. Most electronics draw small amounts of power even when they are turned off, sometimes called "vampire power" or "phantom load." These electronics will drain batteries over time. For rarely used devices, removing the batteries can cut down on energy costs.
Rather than worrying too much about refrigeration, most users get more benefit from finding a cool location with low humidity to store their batteries. While cold storage may extend the shelf life slightly, exposure to heat and humidity will cause a much more rapid decline. Some experts recommend avoiding storing batteries in the kitchen, since using the stove can cause frequent and rapid temperature jumps. Cool closets that do not receive much light are often excellent storage locations.