Last year I went to change the batteries on my label maker
only to find the back encrusted with whitish discharge from leaky alkaline batteries. I have a big stash of rechargeable batteries—would that have saved my label maker from corrosion?
Probably. I talked to our staff writer, Sarah Witman, who recently updated our guide to rechargeable-battery chargers
. Sarah told me that rechargeables are made of generally more corrosion-proof
materials than disposables are. The latest ones are made with low-self-discharge nickel–metal hydride (LSD NiMH) and they tend not to leak the way that alkaline batteries do. They can still corrode but they don’t tend to do it as often.
And you don’t lose much by switching. Our favorite AA rechargeable batteries
, the Energizer Recharge Universal
, have two or more times the capacity of a cheapie disposable. And they have excellent shelf life—maybe not quite as long as disposables, but in our testing we found that they can last for years when stored in a cool, dry place. Sarah said, “Rechargeable batteries are almost always the better choice.”
If you’re trying to decide when to use alkaline over rechargeable, Sarah said, “Things with a low power draw—like some wall clocks, cameras, or flashlights—work better with alkalines because they release power consistently right up until they die, whereas a rechargeable battery’s voltage will get gradually lower and lower over time and cause problems. Also, most smoke-alarm brands
tell you not to use rechargeable batteries, and the US Fire Administration
says a smoke alarm should be powered either by a disposable 9V battery or a built-in battery that’s designed to last up to 10 years. We say in our guide to the best smoke alarms
that you should always check the manufacturer’s instructions to find out what kind of batteries you should be using, and how often to swap them out.”
When you find a device with corroded batteries, here’s Sarah’s advice: “Remove the batteries from your device and recycle them (if you don’t know how to safely dispose of batteries in your area, Earth911
is a great resource). Then you should clean out the battery compartment
with a tablespoon of boric acid diluted in a gallon of water, or else a solution of equal parts vinegar (or lemon juice) and water.”