Does Cold Temperature Affect LED Flashlight Performance?

Morning chillDog mushers, oil riggers, fishermen – these are the types of people likely to use LED flashlights in extremely cold conditions. Indeed, all three of these occupations are plentiful in Alaska, where it’s not unusual for temperatures to drop to -50 degrees Fahrenheit, or even lower. Furthermore, some parts of Alaska see as few as five hours of daylight around the winter solstice, so LED flashlight performance can be very important.

In these situations, special precautions must be taken to ensure one’s equipment functions properly. Extreme cold causes many types of machinery to fail, and LED flashlights are no exception. As we explain below, there are several culprits for poor LED flashlight performance in cold conditions. Fortunately, by understanding how cold impacts the science behind LED flashlights, you can often prevent any drop in performance – a helpful trick indeed, even if your work conditions aren’t quite as cold as those in Alaska.

Battery Performance Decreases as Temperature Drops

Batteries depend on a chemical connection between their negative and positive terminals to produce power. At cold temperatures, this chemical connection occurs more slowly. As a result, you may notice that the batteries in your LED flashlight don’t last as long in very cold weather. That’s because the battery’s slow chemical reaction means less current is available, and the battery soon runs out. (On the flip side, if you want to batteries to retain their charge longer, keep in them in the fridge; rechargeable batteries in particular keep their charge twice as long if they are kept in a chilled environment.)

Regular battery manufacturers’ websites state they should operate well between -4 and 130 degrees Fahrenheit. Lithium batteries, in contrast, are supposed to work between -40 and 130 degrees Fahrenheit. Therefore, many flashaholics depend on lithium batteries in cold weather. Still, many users report that certain LED flashlights won’t work at all when temperatures drop below zero.

That has a lot to do with the amount of current different LED flashlight models require. To enjoy battery-powered flashlight performance even in cold conditions, choose LED flashlights that don’t need much current to operate. Even with low-current models, you may notice a significant decrease in brightness – users report as much as 50 percent lower lux ratings in cold settings.

Finally, remember that batteries are liable to leak, swell or even explode in extreme temperatures. The internal chemistry of an alkaline battery will freeze at around -48 degrees Fahrenheit. At that point, you need to start keeping an eye out for leaking or swelling, which is not unusual in such frigid locales. If you must use batteries on a cold expedition, stash them in your pocket or parka so your body temperature keeps them warmer.

Another option is to use capacitor-powered LED flashlights. These torches power up when you shake them, so there’s no battery drainage issues to worry about – your shivers can provide all necessary power.

LED Bulbs are Safer to Use in Extreme Cold

Incandescent bulbs operate by heating up a metal filament until it glows. This means in very cold temperatures, there is a wide gap between the external temperature and the temperature within the bulb. Indeed, this contrast has been known to cause flashlight bulbs to explode when they are used in cold environs.

In contrast, LED bulbs operate via imbalances in atomic charges, so they do not release heat. As far as safety goes, an LED flashlight is much safer to use in extreme cold than an incandescent flashlight.

Varying Metal Connectors Can Cause LED Flashlight Malfunction in Cold Environments

Those who plan on regularly using LED flashlights in extreme cold would do well to check the metal connectors within their torches. It’s best if all of the connectors are composed of the same metal. Different metals expand and contract at different rates. As temperatures drop, metals shrink. This shouldn’t be a problem as long as all of the metal within your LED flashlight is of one type – otherwise, connections could be thrown off, and the flashlight might not work at all.

In the end, LED flashlights are an excellent choice for cold conditions – as long as they don’t require a lot of current, their internal metal matches, and you use the best batteries available.

[ Photo by: BryanAlexander, on Flickr, via CC License ]

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