‘No, wireless charging doesn’t kill your phone battery’: Scientists explain the myth and how to avoid a ‘lifetime tax’

Wireless charging has become a modern convenience. It’s easy, tidy and strangely satisfying when you feel that little magnetic pull, isn’t it? Just drop your phone on a pad and it starts charging. No complicated cables, no worn out ports, no cluttered nightstand. Some wireless chargers can even power multiple devices at once, and many of them are now built into furniture, cars, and offices.

But even if it’s convenient, it’s not always the case feel as the best option. Charging your phone often takes much longer than just plugging it in, and it may feel warmer when sitting on the mat. This heat has led to concerns that wireless charging could wear out or even damage your phone’s battery over time.

The myth: wireless charging “stresses” your phone’s battery

The supposed myth is that wireless charging damages your phone’s battery, and the extra heat it produces makes your device degrade faster or lose capacity over time.

It’s an idea that seems easy to believe. When you charge wirelessly, your phone often gets noticeably hot, and that heat makes the process harder on the battery than a cable would be.

Add to that the fact that wireless charging can be slower and sometimes inconsistent, and it’s easy to assume that something unnecessary or damaging is happening when you place your phone on a charger.

There is also a common belief that the electromagnetic field used to transfer energy could somehow “stress” the battery or flood it with energy, as if the invisible current is somehow overcharging your phone.

So could the heat we feel during wireless charging actually reduce battery life? Or is it just another misunderstood piece of folklore?

What the experts say

“No, wireless charging doesn’t kill your phone’s battery,” says Associate Professor Ritesh Chugh, a socio-technology expert at Central Queensland University, Australia. “But it can make it slightly warmer, which may have a slight effect on battery health in the long run if you do it frequently.”

To understand why, it helps to know what’s going on behind the scenes. “Wireless charging works by transferring energy through electromagnetic induction,” Chugh explains. “Inside the charging cradle is a coil of wire that creates an alternating magnetic field when electricity passes through it. Your phone has a similar coil on the back. When you place the phone on the cradle, the magnetic field induces an electric current in the phone’s coil, which is then converted to direct current (DC) to charge the battery.”

The main difference between wireless and wired charging is efficiency. “In wired charging, electricity flows directly through a physical connection, making it faster and more efficient,” says Chugh. “When charging wirelessly, the energy must first be converted into a magnetic field and then converted back into electricity inside the phone. »

Kent Griffith, assistant professor of chemistry and biochemistry at the University of California, San Diego, says that while the process is not dangerous, we need to remember that it is less efficient.

“Wired charging is about 95% efficient, while wireless charging is typically 70-80% efficient – ​​sometimes more in ideal conditions,” he says. “Whenever energy is lost, it’s lost as heat, and heat is what can accelerate battery aging.”

However, both experts emphasize that modern phones and certified chargers are designed to handle heat safely.

“Wireless chargers follow standards like Qi (pronounced “chee”), which regulate the amount of energy that can be transmitted and ensure safe alignment and communication between the charger and the device,” Chugh explains. “The phone and charger constantly “talk” to each other, adjusting current and voltage to maintain safe temperatures and prevent overcharging.

So what’s the best way to recharge?

What is the ideal charging configuration? “Occasional wireless charging is perfectly acceptable, and even daily use won’t cause noticeable harm to most users,” Chugh says. “Just be careful of excessive heat.”

He recommends keeping your setup cool and flat. “Avoid charging on soft or heat-retaining surfaces such as sofas or beds. If your phone becomes visibly hot, lift it from the holder for a few minutes to let it cool before resuming.”

Griffith explains that you also need to think about the charger. “Make sure the coils are aligned correctly to ensure the best efficiency and always use a wireless charger that is compatible with your device,” he says.

Chugh adds that you should make sure you have a Qi-certified charger. “They include important built-in safety features such as temperature monitoring, automatic shutdown and foreign object detection.” You can find our recommendations for the best Qi2 options we’ve tested in our guide to the best wireless chargers.

So while wireless charging can make your phone hotter and is a little less efficient than wired charging, it doesn’t kill your battery. And while it might age a little faster, even experts say the actual effect is minimal.

Becca is a TechRadar contributor, independent journalist and author. She’s been writing about consumer technology and popular science for over a decade, covering all kinds of topics, including why robots have eyes and whether we’ll ever know the overview effect. She is particularly interested in VR/AR, wearables, digital health, space technology and talking to experts and academics about the future. She has contributed to TechRadar, T3, Wired, New Scientist, The Guardian, Inverse and many others. His first book, Screen Time, was released in January 2021 by Bonnier Books. She loves science fiction, brutalist architecture, and spending too much time floating in space in virtual reality.