The article mentions (rumored) issues with 3D/overlapping coils that I imagine were needed to allow for multiple device placement anywhere on the mat.

>> Specifically, I’ve heard that they ran too hot because the 3D charging coils in close proximity to one another required very, very cautious power management.

It's not the end of the world if it slows down under multiple devices, and that trivially solves the heat problem.

Is it lack of satisfaction with those tradeoffs? Is there a more fundamental flaw somewhere else? It would be nice to know what actually caused this decision.

Selling point is that you can put all your mobile devices on it. So it’s assumed you’re using more than one and it isn’t a quality experience if you have to sacrifice charging speed for regular use.

The phone is the only one that needs a particularly high wattage. If sharing drops the phone speed by a third, that leaves enough spare capacity to do a watch and airpods at the same time (with both of them getting more percent per hour than the phone). That's still a pretty good experience.

What if they couldn’t get the multi coil design to work charging ANYTHING at high power.

Maybe it was capable of charging the watch and the AirPods just fine, it was the phone’s power demands that were the thing killing it.

Definitely one possibility of many! That's why it's so hard to guess which one or two aspects really tanked it.

Fire? Like, GS Note 7 fire? That would do the trick!

Their design had many overlapping coils which dynamically could be activated. This design would allow you to place the multiple devices on the mat in any orientation.

Apple's plan was to let you place it anywhere on the mat, not on the very small charging sweet-spot.

Worth the huge premium it would've sold for? Probably not for a good deal of people, but it would've sold.

Kinja posted a deal on a dual powered mat for $35 yesterday. Crazy to think that Apple couldnt crack this to reach some level of product that consumers would find attractive.

They wanted you to just toss some devices arbitrarily on the mat and have it "just work". The one you discuss requires alignment, like all others -- for a reason! There's a reason the watch has a magnetic alignment setup.

I thought you might be able to use a 2D array of small loops but a little bit of modeling shows that to be a pretty dumb idea.

That’s what you really want to get too. A big charging mat you just toss everything on.

TBH I don’t find wireless charging today a particularly big win. It’s a bit easier than plugging in a cable. Of course, in the watch, it eliminates a port which is a win for other reasons.

I find Anker 24w fast charging bricks and 10’ lightening cables are a pretty reasonable way to quickly charge Apple devices while still using them. I bought a cheap 5w wireless charging pad to throw my phone on while I sleep.

My problem is that every charging cable I get seems to fail eventually. Either the charging port in the phone gets loose, filled with lint, or the cable mysteriously stops working. Even expensive Ankers. Meanwhile my no-name QI charger that I bought for my LG G3 like 5 years ago is still working perfectly. No parts to loosen or clog.

I don’t even bring my wireless charging when I travel. One more piece of gear to pack and keep track of.

I wouldn't either but now that I have one one my desk, nightstand, and coffee table; I could never go back.

yeah no thx. With how long devices last me now and days the only thing that will accelerate my trade in would be the extra battery wear from wireless charging.

Unless it's a particularly hot charger, a slower wireless charge is actually better for your battery.

In retrospect, I wonder if a motorized device that moves the coils to match the location of your device would have been a better approach.

I had the same thought.

I l suspect that Apple has so little in house experience with moving parts these days that they’d have a hard time shipping a good one that worked this way.

I am curious what you discovered during your modelling.

From a first principles point of view it seems to me like it might just work.

It's hard (very lossy) to try to couple the B fields when the rings are different sizes.

But what if they’re all small and all the same size? In a Grid pattern, like streets between city blocks?

That is not remotely related. Having a mat with two or three separated coils for phones is really easy to do. You basically just glue a few of these together.

AirPower was intended to have basically an entire surface of charging pixels. You could place phones, watches, AirPods, and combos of those on the mat in any orientation. There was also no sweetspot.

By attemping to make inductive charging mats work really well, Apple ran into some big tech contraints.