There is a cruel irony in the fact that we rely more on electronics, like flashlights, during the short days of the winter months when cold weather can wreak havoc on your batteries. Cold weather slows the chemical reactions that take place inside the battery which lowers its ability to deliver the power you need.
Have you ever had a phone or flashlight refuse to work because of cold weather? Depending on the circumstances, that can be anything from a mild annoyance to a very serious situation. Fortunately, you can mitigate the effects with solid gear selection and some planning.
Bring Them Inside… Your Jacket or Sleeping Bag
Your first line of defense against the cold is your clothing. The same goes for your electronics. Anything that you have with a battery should be stored inside your jacket during the day and your sleeping bag at night. This will keep them at a similar temperature to your body which is more than warm enough to keep them running.
This is, perhaps, the best argument for choosing compact, lightweight gear. It needs to be able to fit in pockets or sleeping bag, close to your body, without being a burden. It’s also the reason that I prefer base layers with a chest pocket as this can be a great place to store a smartphone even if you have removed insulation layers during high activity.
If the electronics you are keeping near your body are sensitive to moisture, consider keeping them in a plastic bag or some other vapor barrier to protect them from your perspiration.
Battery and Gear Selection… Choose Wisely
This series has covered a lot of rechargeable electronics in part because I have been working to streamline my own loadout with rechargeable options. However, I will readily admit that rechargeable battery chemistries are often very susceptible to cold weather. There are ways to mitigate this with your battery and gear selection.
Choose the Right Battery – Lithium-ion rechargeable batteries show a significant reduction in efficacy when the temperature of the battery drops to around freezing according to published testing by Panasonic. You are unlikely to notice this until the air temp is colder than the freezing point since factors like the battery’s own warming from internal resistance, warmth from your hand or head, or other factors can play a role but the fact remains that these batteries can begin to suffer performance loss at freezing and more drastic losses below freezing. Recharging at these low temperatures can also be an issue.
Lithium primary batteries like CR123As or lithium AAs, are more resistant to cold. These batteries can usually provide acceptable performance to temperatures well below zero. Energizer for instance, touts that their AA Lithium batteries will retain around half of their capacity down to -40C/F (depending on the rate at which they are discharging). Which brings us to…
Choose the Right Gear – If you are going to select something like a flashlight or headlamp that uses rechargeable batteries, it would be wise to ensure that it can also operate with lithium primary batteries for cold weather use. If you have selected a light that will accept lithium primary batteries, you can then either leave the rechargeables at home when you expect cold temps or at least carry some spare lithium primary batteries as a backup. Options are a good thing.
In the early days of 18650s, it was typical for a light to be made for CR123A batteries but also accept 18650s. This dual-fuel concept is not always the case these days with more and more lights being made specifically for these high-performance batteries. Flashlight makers are chasing lumens and courting flashoholics that seek only the highest performance which can often only be provided by lithium rechargeable batteries. Make sure you understand what kind of batteries your light can take before you open your wallet.
The following are headlamps that accept rechargeable batteries for 3 season use and primary lithium batteries for cold weather. I have purchased all of these, use them, and will be reviewing some in future installments:
If you need even more cold resistance than battery selection alone can provide, consider something like a headlamp with a remote battery pack. Headlamps with battery packs in the back, separate from the light emitting portion of the lamp can be worn with the battery pack under your hat and/or hood to keep the batteries at a good operational temperature. Some headlamps that are built for cold and/or longer runtimes even have larger remote battery packs with a long cable that allows it to be placed in a coat pocket or on the beltline.
Headlamps with remote battery pack options:
There MIGHT Be a Cold Weather 18650 Option… Maybe
I should point out that Nitecore, who is known for selling good quality 18650 batteries (I say selling instead of “making” because most flashlight makers just rewrap batteries from other makers), offers two batteries that they claim are built to handle temps down to -40C/F fairly well. Many people who know more than me speculate that these are just rewrapped Panasonic NCR18650F cells which will cost less but are not as easy to find. I couldn’t find much in the way of testing, other than anecdotes, on these batteries so I am hesitant to spend the money on them when I have other workarounds.
Cold weather doesn’t have to be a death sentence for your electronics. You can mitigate its grip on your batteries with some planning and remember, you should always carry some analog backups where possible, like a map and compass.
Do you have a gear or concept recommendation that fits the On Foot, Off Grid series? Do you have strategies for dealing with cold weather? Tell us about it in the comments below or drop us a line on the Contact page.
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