It's cold: how to protect your phone battery

Woman looking at her smartphone
30/01/2018 - 12h03

Every year, you can see the devastation wreaked by the winter weather: your battery runs out faster and sometimes your mobile phone goes down for no apparent reason. We explain why ... and how to fix it.

Lithium the guilty party                                                                                                                                                                                                                                                                           
Today, while waiting for the generalization of graphene, hailed as the crystalline material of the 21st century, our batteries are still composed of lithium, a technology that is less expensive for manufacturers. So what’s the problem? Lithium is highly sensitive to climatic conditions, especially the cold.
If the temperatures are low or very low, the internal resistance of the battery increases and the voltage decreases. As a result, the battery runs out faster and ... the phone may shut down itself. Indeed, at low temperatures, the smartphone may think that it’s uncharged and shut down without warning.
The problem is noticeable only in direct contact with the cold. As soon as conditions get back to normal, the molecules of the battery warm up and everything starts up again.

And the new phones?
Even the latest smartphones are concerned. For example, the iPhone X tends to block as soon as it is subjected to negative temperatures. The screen can become insensitive. Apple is well aware of the problem and advises using its devices in temperatures ranging from 0°C to 35°C. Yes but ... we don’t always have the choice.

What to do in case of a cold snap?
First of all, just use some common sense. Start by keeping your smartphone in a trouser pocket or, better still, in your jacket, as close as possible to your body. This keeps the temperature of the smartphone at a level sufficient to avoid the risk of a cold snap. If it's really too cold, the pocket of a very light pair of jeans won’t be enough, so opt for the jacket.
Be careful not to warm it up too quickly. Don’t subject it to a change of -3° to 30° in a few seconds. Don’t use a radiator or a hair dryer either: thermal shock could create instabilities. Leave your phone at room temperature and be a little patient (not always easy, we know!).
Cases are available, specially designed for those who work outdoors, able to preserve the temperature of the smartphone. Often the protection is double: falls and cold. These cases may not be top models in terms of beauty, but they do offer a practical solution for phone users who have to contend with the cold.