[Via –Lifehacker]
Image from stock.xchng

Storing batteries at freezing or near freezing temperatures will greatly extend the amount of time they hold a charge, but only for some kinds of batteries. Read on to see which batteries don’t need the meat locker treatment and which benefit.

Over at The Huffington Post, they highlight several unusual things they’ve put in freezers for some benefit—Voodoo masks? If you’re concerned your ceremonial gear has worms, by all means—including batteries. It turns out that not all batteries benefit from the cold however:

A number of studies have shown that storing batteries in the freezer helps them retain their charge longer. This is less true for alkaline batteries (freezing extends their shelf life by only about 5%) than it is for NiMH and Nicad batteries often used in electronics. Keeping NiMH batteries in the freezer can boost battery life by 90%.

At the battery-centric site GreenBatteries they expand on the topic in greater detail:

Alkaline batteries stored at “room temperature” self discharge at a rate of less than two percent per year. So normally refrigerating or freezing them will only help maintain their charge by a tiny amount. Hardly worth the effort of chilling them. However, if alkaline batteries are stored at higher temperatures they will start to lose capacity much quicker. At 85 degrees F they only lose about 5% per year, but at 100 degrees they lose 25% per year. So if you live in a very hot climate or are storing your batteries in a very hot location, it may be worthwhile for you to store your alkaline batteries in a refrigerator instead.

NiMH and NiCd batteries self discharge at a MUCH faster rate than alkaline batteries. In fact, at “room temperature” (about 70 degrees F) NiMH and NiCD batteries will self discharge a few percent PER DAY. Storing them at lower temperatures will slow their self discharge rate dramatically. NiMH batteries stored at freezing will retain over 90% of their charge for full month. So it might make sense to store them in a freezer. If you do, it’s best to bring them back to room temperature before using them. Even if you don’t freeze your NiMH batteries after charging them, you should store them in a cool place to minimize their self discharge.