EEVblog #1369 - Xiaomi Mi Air Wireless Charging BUSTED!

Dave debunks the Xiaomi Mi Air wireless charging system that claims to be able to charge at 5W up to several meters using mm wave RF beam steering technology.
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#Xiaomi #WirelessCharging #Debunk

[Thesignalpath]

It was nice talking to you Dave! I wonder how much this wireless charging unit would cost at the end, it doesn't look cheap. I would be very surprised if they actually end up shipping this in any significant quantity. It could be that they are using this "commercial" as a vehicle for some specialized applications in the future. In our lab using our 95GHz 384-element beamformer I could place my hand in front of the array and feel a warm spot where the beam was going. It is an unusual feeling!

[EdwinSteiner]

Dave: "It's not ethical to produce a product that wastes 99% of 500W."
*Bitcoin has left the chat.*

[deansean]

Finally good to see some actual engineers who check instead of falling for these gimmicks

[Afrotechmods]

It's Energous all over again. Fun fact: Everyone's favourite chairman of the FCC, Ajit Pai, pumped their stock on Twitter and was one of the reasons it went as high as it did.

[eiriseven]

Everyone trying to create these wireless chargers instead of just offering an extra swappable battery for the phone (for obvious reasons).

[phil-sw]

Hi Dave. I am a researcher at an institute where we develop RF power amplfiers in the mmW frequency region. Apart from all the stuff you mentioned there is another caveat with this. To generate the amount of power needed is insanely expensive in the 28 GHz range. To give you a frame of reference: a typical state of the art GaN PA can deliver about 5 to 10 W at 28 GHz. To generate half a kW, you would need about 50 to 100 of these chips (and they are not cheap, hundrets of dollars per IC!). I guess you wouldn't need that many, because your quoted power level was at the wall outlet, but still several chips and a combiner would be required. Absolutely crazy.

[donepearce]

Basically this thing is a microwave oven with no screened box. I'm not going near one. I remember when I used to design radio pagers in the early seventies. We used TV Yagi antennas as dummy loads for the transmitters - we could light up distant fluorescent tubes by pointing at them. We'd work until the headache got too bad.

[cholila-chubut-patagonia]

EEVblog debunking wireless power transmission to charge a phone, while the other 90% of youtube viewers are waiting for free wireless power from Nicola Tesla

[markevans]

Maybe they should sell this as a "microwave space heater" instead.

[unbekannternutzer]

If it is this inefficient they could just market it as a room heater with wireless charging capabilities.

[OzRetrocomp]

I'm looking forward to the next version of Solar Freaking Roadways having built-in wireless recharging tech for EVs!

[SuperSiggiboy]

The world’s most expensive space heater

[ats]

Remember when Apple was having problems with people holding the antenna of their iPhone? Steve Jobs response was "They're holding their phone wrong". Problem solved!

[therealb]

It's about time eevblog took on consumer electronics /"tech" genre. 99% of tech tubers aren't sound in electronics & mostly read off marketing material.

Wish to see you talk more about consumer tech as a lot of cutting edge electronics developments occur in consumer tech space.

[Fifury]

The LG G5 had the perfect solution, fast charging batteries or the ability to swap out the battery! 0-100% charge in less than 10 seconds! In fact it takes longer for the phone to boot up than it does to swap the battery!

[niklaskoskinen]

I mean, at least it'll be a good electric heater in the winter. Almost 100% efficient.

[franciscolevrino]

Xiaomi has phones with more tan 70 hours of battery. Can't you wait half an hour for it to charge every 3 days?

[electrodacus]

This reminds me of that targeted microwave heater from the 70's or around there. The idea was to save energy by just heating the people in the room and no the entire room. In that case this will be a very efficient device but not just for charging the phone.
I do understand that there is huge demand for a product like this so some companies will try to deliver just so they can take advantage of this demand.
In full sun you get 1000W per square meter in ideal conditions so that is about that 10W on a 10x10cm area and that is in the hundreds of THz so one can just use a small solar panel on the back of the phone may get about 2W in ideal conditions with 20% efficient cells and if expensive multi junction cells are used maybe close to 4W.
If you heat the house with electricity then the 1% or lower efficiency is not relevant in winter :)

[WooShell]

That's like somebody learned about PoE and decided "I want this on wifi"...

[Pianet]

Fringe science: 5g deathbeams!
Engineers: Not really....
Startup folks: Hold my beer!