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Wireless charging in mobiles has a big problem: it needs almost 50% more energy than charging the mobile with cable

Wireless charging is great until it stops, and an analysis of its efficiency reveals that this type of feature has a problem: much more energy is wasted.

The Wireless Power Consortium itself has long warned of the inefficiency of wireless charging systems, but a new study makes it clear that almost 50% more energy is used when charging the mobile with a wireless charger compared to doing so with the conventional wired charger.

The Qi standard is the best we have, but it is not very efficient

Being able to transmit power without cables is an old technological dream that has long come true. Wireless chargers that use techniques such as induction have long allowed us to charge our phones or smart watches and make our lives more comfortable, but they do not make it more efficient or cheap.

The Wireless Power Consortium (WPC) already warned years ago (PDF). In a study to evaluate the efficiency of wireless charging they confessed that measuring that parameter was quite difficult because, in the first place, there was no standardized methodology that allowed us to establish how efficient (or inefficient) a wireless charging system was.

It is precisely for this reason that they set out to compare wireless charging technologies such as Rezence and Qi, which is currently the de facto standard in the industry. The first, Rezence, was a great implementation for charging multiple devices on the same surface at the same time, but its cost and efficiency didn’t make it particularly desirable.


In that WPC study, it was concluded that efficiency should be calculated as a spatial average, and after comparing different chargers – all are purchased optionally, something that soon seems to be true with cable chargers as well – became clear. that the efficiency of these technologies it was very poor in the case of Rezence (39.6%) and mediocre in the case of Qi (59.4%).

Wireless charging makes us use almost 50% more energy

The data has now been validated by a OneZero study in which it was compared how much power was needed to charge a Pixel 4 from 0 to 100% using multiple wireless chargers and pitting that average figure against the energy needed to charge it with your cable charger.


The result was overwhelming: on average, wireless charging used 21.01 Wh, while wired charging used 14.26 Wh. That means wireless charging used 47% more power “for the convenience of not connecting a cable” that actually if you connect, but instead of doing it to the mobile you connect it to the wireless charging base, of course.

Wireless charges on mobiles: the technologies and powers of Samsung, Xiaomi and the rest of manufacturers

“In other words,” concluded those responsible for the study, “the phone has to work harder, generate more heat and collect more energy when charging wirelessly to be able to fill a battery of the same size. “Things are even more difficult when we want to go further and think about this system for electric cars, although there are already those who are working on it.

In that experiment, something was clear that was also observed in the Wireless Power Consortium study: The position in which you place the mobile on the wireless charger clearly affects to the efficiency of the load.


It is true that this impact is not particularly worrisome for a single user: the study we carried out in Engadget revealed that the approximate investment we make to charge the mobile it is just 1.5 euros a year.

Imagining a world of mobile without ports and totally wireless

The problem, of course, arises when we look at that on a macro scale. As those responsible for iFixit said when consulted by OneZero: “If the more than 3,000 million smartphones that are in use needed 50% more energy to do so, the thing would end up adding a large amount. So this is a social problem, not a personal one. “

Via | OneZero