Why Your Phone Dies in the Cold

You're scraping the windshield, standing at a Siena or RPI tailgate, or waiting for the bus on Central Avenue, and your phone says 40 percent. A few minutes later it shuts off. Bring it inside, plug it in, and suddenly it shows 35 percent again. You're not imagining it, and in most cases nothing is broken. Here's what's going on and what to do about it.

What cold does to a battery

Phone batteries are lithium-ion, and they work through chemical reactions that slow down when they're cold. Apple explains that a battery's impedance, basically its internal resistance, goes up in the cold. When the phone asks for a burst of power, the battery's voltage can dip too low, and the phone shuts itself off to protect its components.

Apple says this kind of shutdown is more likely when three things stack up: a low charge, an older battery, and cold temperatures. That's why a new phone at 80 percent might be fine outside, while a three-year-old phone at 30 percent quits.

The good news: Apple states that the battery drain from cold is temporary. When the phone warms back up, the battery life returns to normal.

The numbers worth knowing

Apple says iPhones and iPads are designed to be used between 32 and 95 degrees Fahrenheit, and stored between -4 and 113 degrees. A Capital Region January morning is well below that first range. Most Android phones have similar guidance in their manuals.

Don't charge a frozen phone

This one is less known and more important. Battery University, a long-running battery reference site, advises against charging standard lithium-ion batteries below freezing, because metal lithium can build up inside the battery during cold charging. That causes permanent capacity loss and can create a safety risk.

Your phone partly protects itself. Apple says an iPhone that's too cold may slow or stop charging and show "Charging On Hold" until it warms up. But it's still smart to let a phone come up to room temperature before plugging it in. Don't speed things up with a heater, hair dryer, or by setting it on a heat vent. Apple specifically recommends warming the phone gradually before you charge it.

The same goes for a car. Plugging a phone that's been sitting in a frozen car into the charger the moment you start the engine isn't ideal. Give the cabin and the phone a few minutes first.

Simple ways to keep it going

Carry it close to your body. An inside coat pocket stays much warmer than a jacket's outer pocket or a bag.
Head out with a good charge. Since low charge makes shutdowns more likely, top up before a long day outside.
Don't leave it in the car overnight. Apple's storage range bottoms out at -4 degrees, and a parked car in a deep freeze can get colder than that.
A case helps a little. It slows how fast the phone cools down, though it won't keep it warm forever.
Bring a power bank, but keep it warm too. A power bank in a cold bag has the same problem as your phone.

When it's the battery, not the weather

Cold makes a weak battery show itself. If your phone shuts off in mild cold, or at 20 or 30 percent even indoors, the battery has likely worn down. Check it:

iPhone: Settings, then Battery, then Battery Health (on newer iOS versions, Battery Health and Charging). Apple notes the phone may show a message there if the battery needs service.
Android: it varies by brand. Many Samsung phones can run a battery check in the Samsung Members app under diagnostics. Other brands have a battery section in Settings.

A battery replacement is usually a straightforward repair when parts are available for your model. When a phone comes in for random shutdowns, we check the battery and also look at whether something else is going on, like a charging problem or a fault on the board, so you're not replacing a good battery by mistake.

It's not just phones

The same rules apply to anything with a lithium-ion battery: laptops left in the car, wireless controllers, Steam Decks and Switches on a ski trip, earbuds, and cameras. Keep them warm, let them come up to room temperature before charging, and don't store them in a freezing car.

Want us to take a look?

Tech Station is an appointment-only repair shop at 6 Northway Lane in Latham, NY. Pick whichever of these is easiest for you:

Book online: choose a time that works for you on our online booking calendar.
Call us: 518-900-1663 if you'd rather talk it through first.
Text us: send a quick description (and a photo if you can) to 518-900-1663.

We give you an estimate before we start. If a diagnostic is needed, it runs $40 to $100, and we explain it and get your okay before we start. We offer free pickup and delivery within 5 miles of the shop, and a flat one-way fee beyond that. We can't promise every device can be fixed, but we'll always tell you what we find.