https://onezero.medium.com/wireless-charging-is-a-disaster-waiting-to-happen-48afdde70ed9
> We crunched the numbers on just how inefficient wireless charging is — and > the results are pretty shocking > Eric Ravenscraft > > Wireless charging is increasingly common in modern smartphones, and there’s > even speculation that Apple might ditch charging via a cable entirely in the > near future. But the slight convenience of juicing up your phone by plopping > it onto a pad rather than plugging it in comes with a surprisingly robust > environmental cost. According to new calculations from OneZero and iFixit, > 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. (Unless > manufacturers find other ways to make up for the energy drain, of course.) > > On paper, wireless charging sounds appealing. Just drop a phone down on a > charger and it will start charging. There’s no wear and tear on charging > ports, and chargers can even be built into furniture. Not all of the energy > that comes out of a wall outlet, however, ends up in a phone’s battery. Some > of it gets lost in the process as heat. > > While this is true of all forms of charging to a certain extent, wireless > chargers lose a lot of energy compared to cables. They get even less > efficient when the coils in the phone aren’t aligned properly with the coils > in the charging pad, a surprisingly common problem. > > To get a sense of how much extra power is lost when using wireless charging > versus wired charging in the real world, I tested a Pixel 4 using multiple > wireless chargers, as well as the standard charging cable that comes with the > phone. I used a high-precision power meter that sits between the charging > block and the power outlet to measure power consumption. > > In my tests, I found that wireless charging used, on average, around 47% more > power than a cable. > > Charging the phone from completely dead to 100% using a cable took an average > of 14.26 watt-hours (Wh). Using a wireless charger took, on average, 21.01 > Wh. That comes out to slightly more than 47% more energy for the convenience > of not plugging in a cable. In other words, the phone had to work harder, > generate more heat, and suck up more energy when wirelessly charging to fill > the same size battery. > > How the phone was positioned on the charger significantly affected charging > efficiency. The flat Yootech charger I tested was difficult to line up > properly. Initially I intended to measure power consumption with the coils > aligned as well as possible, then intentionally misalign them to detect the > difference. > > Instead, during one test, I noticed that the phone wasn’t charging. It looked > like it was aligned properly, but while trying to fiddle with it, the > difference between positions that charged properly and those that didn’t > charge at all could be measured in millimeters. Without a visual indicator, > it would be impossible to tell. Without careful alignment, this could make > the phone take way more energy to charge than necessary or, more annoyingly, > not charge at all. > > The first test with the Yootech pad — before I figured out how to align the > coils properly — took a whopping 25.62 Wh to charge, or 80% more energy than > an average cable charge. Hearing about the hypothetical inefficiencies online > was one thing, but here I could see how I’d nearly doubled the amount of > power it took to charge my phone by setting it down slightly wrong instead of > just plugging in a cable. > > Google’s official Pixel Stand fared better, likely due to its propped-up > design. Since the base of the phone sits flat, the coils can only be > misaligned from left to right — circular pads like the Yootech allow for > misalignment in any direction. Again, the threshold was a few millimeters of > difference tops (as seen below), but the Pixel Stand continued charging while > misaligned, albeit slower and using more power. In general, the propped-up > design helped align the coils without much fiddling, but it still used an > average of 19.8 Wh, or 39% more power, to charge the phone than cables. > > On top of this, both wireless chargers independently consumed a small amount > of power when no phone was charging at all — around 0.25 watts, which might > not sound like much, but over 24 hours it would consume around six > watt-hours. A household with multiple wireless chargers left plugged in — > say, a charger by the bed, one in the living room, and another in the office > — could waste the same amount of power in a day as it would take to fully > charge a phone. By contrast, in my testing the normal cable charger did not > draw any measurable amount of power. > > While wireless charging might use relatively more power than a cable, it’s > often written off as negligible. The extra power consumed by charging one > phone with wireless charging versus a cable is the equivalent of leaving one > extra LED light bulb on for a few hours. It might not even register on your > power bill. At scale, however, it can turn into an environmental problem. > > “I think in terms of power consumption, for me worrying about how much I’m > paying for electricity, I don’t think it’s a factor,” Kyle Wiens, CEO of > iFixit, told OneZero. “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.” > > To get a frame of reference for scale, iFixit helped me calculate the impact > that the kind of excess power drain I experienced could have if every > smartphone user on the planet switched to wireless charging — not a likely > scenario any time soon, but neither was 3.5 billion people carrying around > smartphones, say, 30 years ago. > > “We worked out that at 100% efficiency from wall socket to battery, it would > take about 73 coal power plants running for a day to charge the 3.5 billion > smartphone batteries once fully,” iFixit technical writer Arthur Shi told > OneZero. But if people place their phones wrong and reduce the efficiency of > their charging, the number grows: “If the wireless charging efficiency was > only 50%, you would need to double the [73] power plants in order to charge > all the batteries.” > > If everyone in the world switched to wireless charging, it would have a > measurable impact on the global power grid. > > This is rough math, of course. Measuring power consumption by the number of > power plants devices require is a bit like measuring how many vehicles it > takes to transport a couple dozen people. It could take a dozen two-seat > convertibles, or one bus. Shi’s math assumed relatively small coal power > plants outputting 50 MW, as many power plants in the United States are, but > those same needs could also be met by a couple very large power plants > outputting more than 2,000 MW (of which the United States has only 29). > > However, the broader point remains the same: If everyone in the world > switched to wireless charging, it would have a measurable impact on the > global power grid. While tech companies like Apple and Google tout how > environmentally friendly their phones are, power consumption often goes > overlooked. “They want to cover the carbon impact of the product over their > entire life cycle?” Wiens said. “The entire life cycle includes all the power > that these things ever consumed plugged into the wall.” > > There are some things that companies can do to balance out the excess power > wireless chargers use. Manufacturers can design phones to disable wireless > charging if their coils aren’t aligned — instead of allowing excessively > inefficient charging for the sake of user experience — or design chargers to > hold phones so they align properly. They can also continue to offer wired > charging, which might mean Apple’s rumored future port-less phone would have > to wait. > > Finally, tech companies can work to offset their excesses in one area with > savings in another. Wireless charging is only one small piece of the > environmental picture, and environmental reports for major phones from Google > and Apple only loosely point to energy efficiency and make no mention of the > impact of using wireless chargers. There are many ways tech companies could > be more energy-efficient to put less strain on our power grids. Until > wireless charging itself gets a more thorough examination, though, the world > would probably be better off if we all stuck to good old-fashioned plugs. -- Kim Holburn IT Network & Security Consultant T: +61 2 61402408 M: +61 404072753 mailto:k...@holburn.net aim://kimholburn skype://kholburn - PGP Public Key on request _______________________________________________ Link mailing list Link@mailman.anu.edu.au http://mailman.anu.edu.au/mailman/listinfo/link
