[7granddad]

What I don't follow is how other multi-charging mats do exactly this. According to the article, by their estimation it was powerful harmonic EM interference that did AirPower in. If AirPower were only powering 3 coils at a time like other multi-charging mats why did it run into this problem when others had not

[hmottestad]

I guess it is because no other mat has overlapping coils. In the apple one they wanted you to not care where you put down your devices. Since they have so many coils, it then becomes likely that the 3 active ones overlap.

[radiorental]

There has to be something else going on here. It strikes me as relatively simple to have the device talk to the mat and optimise on which coil was providing the most current draw.

I suspect that engineering does have a design that meets regulations but they couldn't get the cost down. I.e. the extra circuitry in both the met and possibly the devices to precisely sense which coil(S) are providing optimal charging is cost prohibitive.