Electronics in the cold: keeping the things you depend on alive

Modern outdoor travel leans heavily on electronics: navigation, communication, avalanche transceivers, headtorches, cameras, watches. Nearly all of it is powered by lithium cells, and lithium cells behave badly in the cold.

What cold does

Battery chemistry slows as temperature falls, which reduces both the available capacity and the current the cell can deliver. A phone that lasts a full day in summer can die in a couple of hours at genuinely low temperatures.

Worse, the failure is often abrupt. A device reports a healthy charge, then shuts down without warning when a load is applied, because the cell cannot deliver the current. Warm it up and the same battery reports charge again — the capacity was there, it just could not be accessed.

This is why "my phone said sixty percent and then switched off" is such a common winter complaint. It is normal behaviour, not a fault.

Keep everything warm

The single most effective measure. Devices live in an inside pocket, against your body, under insulation. Not in a pack, not in an outer pocket, not in a chest pocket on the outside of a shell.

Spare batteries and power banks go in the same place. A cold power bank cannot charge a cold phone; both need to be warm for the transfer to work efficiently.

At night, take batteries into the sleeping bag. A phone left in a tent vestibule overnight in real cold will be functionally empty by morning.

Reduce the load

Aeroplane mode is the biggest single saving. A phone searching for a signal in a valley with no coverage burns power continuously at maximum transmit power, which in the cold is exactly the load the battery cannot supply.

Turn the screen brightness down. Screens are a major consumer, and a bright screen also destroys your night vision.

Close background applications, turn off anything that polls — mail, messaging, fitness tracking — and download maps for offline use before you leave so the device is not trying to fetch tiles.

GPS itself is relatively economical; what drains the battery is the screen and the radios.

Charging in cold conditions

Do not charge a lithium battery below freezing. Charging a cold lithium cell can cause permanent damage and, in extreme cases, is genuinely unsafe. Warm the device first — inside a jacket for twenty minutes — then charge.

Solar panels work poorly in winter: low sun angle, short days, cloud, and cold cells. On a winter trip, carry capacity rather than expecting to generate it.

Size a power bank on the assumption that everything will perform worse than the specification suggests. Capacity ratings are quoted at room temperature.

Physical problems beyond the battery

Touchscreens do not work with gloves unless the gloves have conductive tips, and even then unreliably. Cold fingers also work poorly on capacitive screens. Learn which functions of your device you can operate with physical buttons.

Condensation. Taking a cold device into a warm hut or tent causes moisture to condense inside it. Put it in a plastic bag before bringing it into the warm, and let it come up to temperature inside the bag.

Screens crack more easily in cold and plastics become brittle. A drop that would be survivable in summer may not be.

Cables stiffen and break at the connector.

Redundancy, which is the real answer

The important principle: no electronic device should be your only means of doing anything essential.

Navigation. Carry a paper map and a compass, and be able to use them. This is not nostalgia — a map does not run out of battery, does not shatter, and works with mittens on. Anyone relying solely on a phone for navigation in winter is one dropped device from a serious situation.

Light. A second torch or a set of spare batteries.

Communication. A whistle, and a plan left with someone at home.

Time. A simple watch, which is also useful for turnaround discipline when the phone is off.

Transceivers, specifically

Avalanche transceivers use replaceable alkaline cells for exactly these reasons: they behave more predictably as they drain and their state of charge is easier to judge. Follow the manufacturer's guidance, replace them well before they are exhausted, and never substitute rechargeable cells unless the manufacturer explicitly permits it.

And keep phones and other electronics well away from a transceiver, both while transmitting and, more importantly, while searching. Interference degrades range and accuracy at exactly the moment those matter most.