News

PSA: Never charge your smartphone if it has been in freezing temperatures

Give your gadgets time to warm back up to room temperature before plugging them in.

by
Joe Rice-Jones
January 11, 2022

Image: KnowTechie

It’s a new year and freezing temperatures are blanketing many states right now. Even if you aren’t actively seeking out the snow at your favorite ski hill, cold temperatures are seeping into our homes and cars.

While using a smartphone or another tech gadget in the cold might be fine, we’re here today to remind you not to charge your lithium-ion-powered tech when the device is below freezing.

Just don’t. Wait until it has warmed up to room temperature, whether you were out on the slopes or you just snagged your new iPhone delivery off the porch. We’ll tell you why.

Wait, why shouldn’t you charge your devices if they’re freezing?

ipad pro usb-c port with cable — Image: Joe Rice-Jones / KnowTechie

There are two reasons, and neither is good. See, one damages your device, irreparably, and the other could damage you. Yeah, we told you neither was good. If your device is powered by lithium-ion, as most smartphones, tablets, and laptops are, you should never charge them if they’re below freezing.

You might know that all batteries degrade chemically, which is why modern mobile operating systems have a battery health display to show you how it’s aging. Every battery has a rough lifespan with charge and discharge cycles, and that display keeps track of it.

That’s under normal conditions, but if your lithium-ion battery is below 32°F/0°C, some funky stuff happens. A single cold charge can instantly reduce the capacity of that battery, and it’s proportional to the speed of the charging. Yes, that means your fancy, new fast-charging chargers will kill your battery forever, possibly in one charge.

iphone battery health — Image: KnowTechie

Your device’s lifespan is reduced, that’s bad news. The really bad news is that your lifespan could be reduced; as you’ve turned your phone/flashlight/etc into a grenade with an unknown fuse length. Really. We’re not joking around.

The worrying thing here is that other than the shortened charge capacity, you won’t otherwise know you’re putting something liable to explode in your pocket. It’s a case of when not if. The responsible thing to do is to dispose of that battery, so find your local battery recycler and pay them a visit.

Here’s why you can’t charge your smartphone when it is below freezing

We found a long explanation for why on Stack Exchange, by user metacollin. If you want a longer explanation, it’s worth reading the full thing. Otherwise, stick around for the TL:DR version.

See, lithium batteries don’t work like other batteries. All batteries have two sides, an anode, and a cathode. In a normal battery, electrons move to the anode when charged; in a lithium-ion battery, it’s lithium ions that move across to the anode from the cathode. It’s a little like moving water from one sponge to another.

And just like our sponge analogy, when the battery of your smartphone is freezing, the anode can’t absorb the lithium ions like before. It gets coated in pure lithium instead. Now think back to science class, and that impressive “lithium dropped into water” reaction. Now imagine that happening while in your jeans.

Safe charging in cold temperatures

We’re not saying you can’t charge your devices if it’s cold out. We’re saying you have to be careful if you think your lithium-ion battery is below 32°F/0°C. If you think it’s that cold, let it warm up a little before you plug it in to charge.

The good news is that using your lithium-ion batteries in these temperatures won’t cause the same effect. Take your selfies, listen to your tunes, call your friends and family. Just stay away from the charger.

Have any thoughts on this? Let us know down below in the comments or carry the discussion over to our Twitter or Facebook.