Does using a very cold iPhone risk damaging it?
November 15, 2017 6:26 AM   Subscribe

When I use my iPhone in cold weather, it sometimes turns itself off. I thought that was because the battery performs poorly in the cold, so I got an external battery with a cable, so I could keep using my phone while the battery stays warm in my pocket. But then I read that the iPhone turns itself off by design, to protect itself from usage outside its operating range. So is it a bad idea to override that by using the external battery?

I don't know whether it's just the iPhone's battery that it’s protecting by shutting off, so using it on an external battery is fine, or whether other components are at risk when I’m using an external battery.

I have an iPhone 6, and I have the same question about other models. I need to use it near-continuously for a couple of hours at a time, at temperatures in the 20's-30's F, and occasionally lower. In that weather, the battery decreases quickly and in big jumps. It sometimes goes from ~30% to dead instantly, turning itself off. Once I get home and plug it in, it immediately shows that there's still battery life left.

Or, if I plug it in to the external battery while still outside, it comes on and seems to function fine -- but am I screwing up my phone in some unseen way? I’ve googled around and found conflicting advice, so I’m looking for an engineering perspective or other informed opinion.
posted by daisyace to Technology (3 answers total)
Best answer: Batteries respond really badly to cold weather, so you will definitely experience reduced life in those environments. I would expect the battery to bounce back a little bit when it warms up, which would explain what you're seeing when you bring the phone home.

As far as actual damage you may be incurring to the phone - the primary failure mode here is thermal shock as components in the phone heat up rapidly compared to the outside temperature. The temperature difference causes solder joints to flex and potentially crack. This is more of a fatigue-related failure, which would manifest itself by an overall reduced life of the phone. That being said, I would not consider 20F to be an "extreme" temperature, even for commercial grade products; I would expect products of that quality to be tested down to 0F or even lower, so I don't think you have to worry too much about it.

(Source: ten years of experience running environmental testing on electronic hardware)
posted by backseatpilot at 6:34 AM on November 15, 2017 [5 favorites]

If the external battery pack is completely inside your coat (say, in a shirt pocket), your body heat should keep it from getting too cold. When I’ve used my cameras in outside temperatures below the reliable operating range of their batteries, I’ve put a spare battery in my front jeans pocket next to a hand warmer, so I could swap in a warm battery when the one in the camera gets too cold. That said, the specs for the iPhone 6 (and every other model I checked) say:

Environmental Requirements
Operating ambient temperature: 32° to 95° F (0° to 35° C)
Nonoperating temperature: -4° to 113° F (-20° to 45° C)

The phone shouldn’t be damaged just by being in temperatures below freezing, but I'm not surprised it shuts itself down.
posted by fedward at 7:11 AM on November 15, 2017

Response by poster: Thank you!
posted by daisyace at 8:26 AM on November 16, 2017

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