Why do phone batteries drain faster in winter?

Don’t worry, it’s probably not time to change your phone’s battery just yet – the cold temperatures are the problem.

Inside our phones are lithium-ion batteries that we can see in many other electronic devices such as toys, wireless headphones, cordless tools, kitchen appliances, but also in electric vehicles or electricity storage systems. Batteries, just like people, work best at room temperature, so exposure to temperatures below or above 20°C can significantly affect their performance and thus the autonomy of our devices. So if your phone battery seems to be draining these days, don’t worry, you’re not the only one.

High temperatures

Although room temperature is ideal for battery operation, many manufacturers advertise its specifications at 27°C, as batteries perform better at higher temperatures. In such conditions, the chemical reaction in them takes place more easily, and the result is a higher voltage and capacity. However, it is not without reason that it is said that the biggest enemies of batteries are time and temperature – no matter what you do, they will degrade over time, and the speed of this process depends on the frequency of use at higher temperatures. Thus, a battery used frequently at a temperature of 30°C will have a 20% shorter life, while with frequent use at 40°C, its life is 40% shorter than that of a battery used at room temperature.

Low temperatures

On the other hand, if batteries are used at lower temperatures, they lose their voltage and capacity. Drivers of electric cars know this best, because their vehicles have a shorter range during the winter, but not only because they use extra energy to heat the cabin, but also because in these conditions the resistance in the batteries themselves increases. At extreme temperatures of -20°C, lithium-ion batteries can lose around 50% of their capacity.

So, although we popularly say that our phones wear out faster, it’s not about more energy consumption, but about less battery capacity. Fortunately, this decrease in capacity is not permanent, but will increase again when the device warms up. Because of this, it is recommended that you keep your phone in the inside pocket of your jacket during cold days and use it as little as possible in the cold if autonomy is an important factor for you.

In the image below, you can see how the 18650 lithium-ion battery, with an advertised capacity of 2,800 mAh, behaves at different temperatures.

Fortunately, apart from the reduced capacity, i.e. less autonomy of the battery in the shadow, the average phone user is not in danger of permanently damaging their battery in these conditions. Many other components of our devices will begin to cause problems much earlier than the battery, and because today’s phones are smart, they will certainly disable further use of the device if they judge that it may lead to failure.

However, what will damage the battery and is not recommended to do during winter is to charge your device outside or in cold rooms. Although lithium-ion batteries can be safely charged in a temperature range of 5°C and 45°C, charging at lower temperatures will take longer due to increased resistance and may cause permanent performance degradation.

If you want to use your phone in extremely cold or hot temperatures, consider buying a rugged device that meets the US military MIL-STD-810 standard, such as the Samsung XCover6 Pro, Ulephone Armor X6 Pro, or Oukitel WP19.