A word about lights and batteries

Winter ultras provide a robust proving ground for the battle between nature and technology. Despite all of our best efforts, many of the electronics that we come to depend on simply don’t work well when the temperature drops. In addition, the winter months reduce the amount of natural light that is around, causing us to rely on artificial means of illumination for longer periods of time. Therefore, it’s prudent that we say a few things about batteries, lights, and extreme cold.


One of the biggest issues for technology in the cold is how batteries react to it. If you remember back to some of you elementary school science lessons, you learned that batteries are a chemical reaction. Various chemicals and metals interact within the cells of a battery to produce electric current, and thereby power our devices. When the temperature drops, these chemical reactions have a much harder time working. That’s why it’s important to understand which batteries work better in the cold, and which ones do not.

Alkaline and NiMH batteries are two of the most popular types out there. Many headlamps use AA or AAA batteries, and rechargeable NiMH batteries are a great way to keep your device powered without being wasteful. However, as soon as the temperature hits 32F/0C, these types of batteries start to fail very quickly. The chemical reactions inside of them simply don’t work.

There is one type of battery that is rated to work, even into the negative digits, and that is Lithium Ion (li-ion). These batteries hold their charge much better, even in extreme cold temps. Rechargeable li-ion AA and AAA batteries are not nearly as prevalent as NiMH yet, so in the meantime it’s best to stick with single use versions. These are the only batteries that are going to reliably last 12+ hours in extreme cold.

Cell phone batteries are rechargeable li-ion, however in the cold the chemical reaction slows down to the point where they phone cannot draw enough power. Your phone may suddenly drop from 60% battery life to 1%. The battery did not drain that fast, but it simply could not keep up with the draw that is required to run a small pocket supercomputer. Keeping your phone warm and close to your body is the best way to keep it operating throughout a long cold night.


With the winter cold comes darkness. Not only are the days shorter during the winter, but the angle of the sun is lower, giving everything a dimmer light. Therefore, it’s important to have lots of light when out in the winter time. The St Croix 40 takes place almost completely in the dark, so you will have plenty of opportunity to use your lights throughout the race.

The key with darkness in the winter time is to have lots of very bright lights. The reason that winter ultras require so many lights is not just because it’s dark out. Snowmobilers are also bundled up in the cold and their range of vision may not be what it would be in warmer temps. Therefore, the best thing that you can do is make yourself as visible as possible. In addition to reflective material, you also need lots of lights.

The winter ultras in the midwest have gone to requiring larger lights in recent years because the smaller ones just aren’t visible enough. By the time a snowmobiler is able to pick out the light from the darkness it might be too late. It’s vitally important to not skimp on your light setup. Larger bike tail lights are some of the best options around. They offer multiple flashing modes, and have much greater quantities of bulbs and LEDs than smaller lights. Do yourself a favor and invest in some nice lights. Good quality ones will last you year after year.

Surviving in the cold is a challenge, but it’s one that humans have met head on. With the right equipment and some knowledge, it’s possible to exist in our extreme winters, and even thrive. We hope that your efforts over these winter months prove fruitful, and you even come to enjoy these beautiful winter days.


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