Wireless Charging Is Shockingly Inefficient (But Could Apple’s Mysterious Magnetic Ring Fix It?)

iPhone Wireless Charging Apple Watch Charger Credit: Melvin Thambi / Unsplash
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You’re probably already aware that wireless charging is dramatically slower than simply plugging your iPhone in — even if you’re using a high-speed wireless charger — but what you may not realize is that it’s actually far less efficient as well in terms of how much of the power that’s being used is actually getting to your iPhone.

Many folks with a basic understanding of electronics have always realized that wireless charging has to be at least slightly less efficient by its very nature — even wired charging results in some energy being lost as heat — but now a new set of calculations from OneZero and iFixit have demonstrated that it’s actually a lot worse than most of us suspected.

In fact, according to Eric Ravenscraft, wireless charging could actually be an environmental disaster waiting to happen as more and more users turn to the much more convenient technology. The problem is that since wireless charging draws more power from the grid to produce the same amount of juice for your iPhone, it’s going to place an even greater demand on power plants as it scales up.

Wireless charging is drastically less efficient than charging with a cord, so much so that the widespread adoption of this technology could necessitate the construction of dozens of new power plants around the world.

Eric Ravenscraft, OneZero

Specifically, the team’s calculations show that wireless charging on average uses around 47 percent more energy than simply plugging in a cable to charge your phone.

For his tests, Ravenscraft used a Google Pixel 4 and multiple wireless chargers, along with a high-precision power meter to measure power consumption. Charing the Pixel 4 from completely dead to 100% took approximately 14.26Wh when using a cable, while a wireless charger required 21.01Wh to achieve the same charge level.

As Ravenscraft notes, while 47 percent may sound like a big number, the extra power consumption is quite negligible on an individual basis. It’s not going to cost you, the consumer, any significant amount of money to charge your iPhone wirelessly instead of plugging it into a cable — it’s about the same as leaving an LED light bulb on for a few extra hours — but of course as it scales up to the billions of smartphones being used around the world, it can add up to a pretty significant environmental impact.

If all of a sudden, the 3 billion-plus smartphones that are in use, if all of them take 50% more power to charge, that adds up to a big amount. So it’s a society-wide issue, not a personal issue.

Kyle Wiens, iFixit CEO

Ravenscraft got together with iFixit to do the math and figure out exactly what the environmental impact could be if every smartphone user on the planet switched to wireless charging. According to their calculations, it would take 73 typical 50MW coal power plants running for a day to provide the power to charge 3.5 billion smartphone batteries full at a 100% efficiency level — a number that could easily double if everybody was using wireless charging instead.

Positioning Is Critical

While you can’t really plug your iPhone in the wrong way and expect it to charge properly, wireless charging presents an additional challenge that actually has a measurable impact on charging efficiency, and that’s how well-positioned your device is on the charging mat.

In fact, when using a Yootech charging pad, Ravenscraft found that it actually took 80 percent more energy for his Pixel 4 to fully charge, due to “setting it down slightly wrong.” This was less of an issue with Google’s official Pixel Stand, since the upright design ensured that the coils were properly aligned at least along the vertical axis, although it was still possible for it to be misaligned from side to side.

Even a slight misalignment resulted in some fairly significant differences in charging performance and efficiency, and with that in mind we might have an explanation for the mysterious magnetic ring that we heard could be coming to the iPhone 12.

With Apple’s strong focus on environmental responsibility, this kind of wasted energy would be an abomination, and we can definitely see Apple leading the way in ensuring that wireless charging operates with the maximum level of efficiency possible, and as we’ve seen from OneZero’s study, the biggest factor is ensuring that the iPhone gets placed on the charger in properly alignment to the charging coils.

While it would be theoretically possible for a ring of magnets to slightly help get the proper alignment with any charging coil, the best way to implement this would be a matching ring of magnets in the wireless charging on the other end, ensuring that the two devices would always meet up in the exact same way, in perfect alignment for maximum efficiency.

This would also help to make a lot more sense of reports that Apple is working on a single-device charging pad, since even though there are several cool things Apple could bring to the table, certainly built-in magnets for proper alignment would be a really big one, especially if Apple can get up on stage and talk about how doing so will help users save money (even if the amounts are negligible in reality) and help the environment.

Further, there’s a good chance that Apple would lead the way on this, since the popularity of the iPhone would certainly encourage other wireless charging manufacturers to take advantage of the new magnetic alignment feature for ideal compatibility with the iPhone 12.

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