Author Topic: Wi-Charge Infrared Wireless Charging  (Read 7187 times)

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Offline EEVblog

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Wi-Charge Infrared Wireless Charging
« on: May 30, 2018, 11:58:25 pm »
Linus tested it:

But didn't us a power meter, no mention of system efficiency, or how the directional aspect works.

 

Offline Precious Roy

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wi-charge wireless charging (de bunk?/Tip)
« Reply #1 on: May 31, 2018, 07:12:10 pm »
hey,

I just saw this and thought of the other wireless room charging we saw a while ago and i was wondering what you all think about this one. Real and practical or fake/unusable?

http://www.wi-charge.com/

and an actual vid of it in action by a reputable source:


Roy
 

Offline thm_w

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Re: Wi-Charge Infrared Wireless Charging
« Reply #2 on: May 31, 2018, 08:16:20 pm »
He mentioned something like 0.5W for the small phone case and 1.5W maximum for the larger receiver unit for the speaker. So not uselessly low but still significantly less than a traditional charger.
I can see niche use cases. Although the example given (cell phone chargers in coffee shop), could be achieved other ways. You could simply use a larger internally battery, and take the units to a charging dock at the end of the day for example. 1.5W * 10hr = 15WHr, not much more than a single 18650 lithium cell.

No mention of efficiency no, in the comments someone calculated around 20-30% optimal (photovoltaic efficiency combined with IR LED/laser efficiency).
 

Offline CJay

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Re: Wi-Charge Infrared Wireless Charging
« Reply #3 on: May 31, 2018, 08:52:09 pm »
So pretty much 'Completely useless test, Holy Sh*t"
 

Offline BrianHG

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Re: wi-charge wireless charging (de bunk?/Tip)
« Reply #4 on: May 31, 2018, 10:30:02 pm »
Laser beamed IR does sent power to solar cells exactly as advertised.  What they are not saying is that to get 1 watt out at the other side, you need a good 5-10 watts of optical power landing directly on the solar cell and the power efficiency of the laser to convert DC current into watts isn't also that accurate as well as aiming the beam directly on target, not to mention that they split the beam to multiple targets.  And you need un-obstructed line of sight for only 1 watt of charging power, on phones today which are all display screen.

My whole point about all this tech is that Lithium-Nitrogen batteries are coming soon doubling the current battery size/mah capacity.  Unless you don't sleep at all, many handheld devices will no longer need to be charged from day to day.  A decade from now when Lithium Oxygen becomes available with over 3x the current capacity, not to mention the portable electronics drawing less current as well as more space for the battery as what final little streamlining there is which can be made, there will be no need to continuously charge our devices as we use them during the day.

This will be a temporary product seeing a limited use at best unless that solar cell can be hidden inside the LCD screen of a phone for near free, available on all phones being sold, it will be a fancy luxury product.
« Last Edit: May 31, 2018, 10:33:38 pm by BrianHG »
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Offline EEVblog

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Re: Wi-Charge Infrared Wireless Charging
« Reply #5 on: June 01, 2018, 12:06:50 am »
No mention of efficiency no, in the comments someone calculated around 20-30% optimal (photovoltaic efficiency combined with IR LED/laser efficiency).

I've been talking to the marketing dude on Twitter:

 

Offline EEVblog

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Re: Wi-Charge Infrared Wireless Charging
« Reply #6 on: June 01, 2018, 03:06:15 am »
More, and it doesn't add up.

 

Offline EEVblog

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Re: Wi-Charge Infrared Wireless Charging
« Reply #7 on: June 01, 2018, 03:07:27 am »
Been going at this for 6 years and they won't release data  ::)
But of course happy to target huge blogs for publicity that they know won't ask hard engineering questions - the usual story.

« Last Edit: June 01, 2018, 03:12:46 am by EEVblog »
 

Offline EEVblog

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Re: Wi-Charge Infrared Wireless Charging
« Reply #8 on: June 01, 2018, 03:44:58 am »
Does anyone know how to find the FDA approval document / test results for this thing?
Asking for a friend  ;)
 

Offline thm_w

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Re: Wi-Charge Infrared Wireless Charging
« Reply #9 on: June 01, 2018, 10:14:45 pm »
Tried searching here, but its all classifications: https://www.fda.gov/Radiation-EmittingProducts/default.htm
Can only seem to look up medical devices, not radiation devices.

Is it possible the document is not public? and FDA is just saying to them, it falls within some classification and that is OK (ie power is less than xmW for a laser product).
http://www.wi-charge.com/press/wi-charge-secures-fda-approval-to-charge-all-your-devices-using-infrared-beams/

Did some FCC searches but nothing either, probably way too early.
https://apps.fcc.gov/oetcf/eas/reports/GenericSearch.cfm
 

Offline StillTrying

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Re: Wi-Charge Infrared Wireless Charging
« Reply #10 on: June 02, 2018, 04:30:33 pm »
"End-to-end efficiency is comparable to an LED light."

They might as well say that the efficiency is comparable to a push-bike, except that would actually make more sense!
Perhaps they're just referring to the round white light as being as efficient as a LED bulb, because it is a LED bulb!

The intensity in their beams must be many 1000's of times that of sunlight, and yet the video cameras never pick up any dot or speck anywhere.

"Nearly 100% link efficiency."   http://www.wi-charge.com/technology/

So now we know the efficiency, although they don't say power efficiency.LOL
CML+  That took much longer than I thought it would.
 

Offline Marco

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Re: Wi-Charge Infrared Wireless Charging
« Reply #11 on: June 02, 2018, 11:14:30 pm »
Are there cheap high power LEDs in the >1400nm range? Because I don't think I want to look into that thing and have the light reach my retina.
 

Offline BrianHG

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Re: Wi-Charge Infrared Wireless Charging
« Reply #12 on: June 04, 2018, 12:52:50 am »
The company's website shows these chargers being installed in a coffee shop.  Who leaves their expensive phone on the table in plain sight in a crowded public coffee shop just so it may charge?
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Offline EEVblog

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Re: Wi-Charge Infrared Wireless Charging
« Reply #13 on: June 04, 2018, 12:55:57 am »
"End-to-end efficiency is comparable to an LED light."

They might as well say that the efficiency is comparable to a push-bike, except that would actually make more sense!
Perhaps they're just referring to the round white light as being as efficient as a LED bulb, because it is a LED bulb!

The intensity in their beams must be many 1000's of times that of sunlight, and yet the video cameras never pick up any dot or speck anywhere.

"Nearly 100% link efficiency."   http://www.wi-charge.com/technology/

So now we know the efficiency, although they don't say power efficiency.LOL

Calculating best case system efficiency is not rocket science:


References:
http://www.semiconductor-today.com/news_items/2014/JAN/EPISTAR_080114.shtml
https://www.extremetech.com/extreme/252295-layered-solar-cell-can-capture-wavelengths-solar-spectrum
http://brolis-semicon.com/near-infrared-components-systems/

I'm corresponding with them on this and have asked them to comment on my numbers.
Will do a video when they reply and see if they still want to stand behind their efficiency claim
 

Offline EEVblog

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Re: Wi-Charge Infrared Wireless Charging
« Reply #14 on: June 04, 2018, 01:22:21 am »
They just replied and are implying zero loss in the capture area because (presumably) the entire IR dot is small enough to be fully enclosed within the solar panel area.
 

Offline EEVblog

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Re: Wi-Charge Infrared Wireless Charging
« Reply #15 on: June 04, 2018, 01:28:12 am »
They have come back and said that system efficiency is "greater than 5% and lower than 27%" (the 27% figure I got from assuming no capture area loss).
 

Offline coppice

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Re: Wi-Charge Infrared Wireless Charging
« Reply #16 on: June 04, 2018, 01:44:01 am »
They have come back and said that system efficiency is "greater than 5% and lower than 27%" (the 27% figure I got from assuming no capture area loss).
So, its 6%. Maybe 5.5% on a bad day. :)
 
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Offline EEVblog

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Re: Wi-Charge Infrared Wireless Charging
« Reply #17 on: June 04, 2018, 01:58:57 am »
They have come back and said that system efficiency is "greater than 5% and lower than 27%" (the 27% figure I got from assuming no capture area loss).
So, its 6%. Maybe 5.5% on a bad day. :)

My guess would be 10% if they can hit the target 100%
I wonder how well they track the trains in that demo. I need to get data on those trains, but you probably only have to hit a small percentage of the time with a high energy short pulse to keep the train going.
Something like a phone on a desk might need some sort of feedback to "dial in" the laser. i.e. it measures the solar cell energy output and feeds back that data as the beam hunts round.
 

Offline JohnnyMalaria

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Re: Wi-Charge Infrared Wireless Charging
« Reply #18 on: June 04, 2018, 02:05:24 am »
Does anyone know how to find the FDA approval document / test results for this thing?
Asking for a friend  ;)

It's not a medical device so the FDA has no involvement.  (If it were then all the correspondence between the manufacturer and the FDA would be publicly accessible though heavily redacted).


e.g., https://www.accessdata.fda.gov/drugsatfda_docs/nda/2006/021254s000toc.cfm (my baby!)
« Last Edit: June 04, 2018, 02:13:49 am by JohnnyMalaria »
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Offline BrianHG

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Re: Wi-Charge Infrared Wireless Charging
« Reply #19 on: June 04, 2018, 02:45:21 am »
Looking at the second half of this article, if they are using the right solar cell tuned to the laser diode, the solar cell will have close to 100% efficient power recovery: http://blog.innovation4e.de/en/2016/09/12/power-by-light/  Though I find it doubtful that they are making their own silicon solar cells.

This does not speak to the efficiency of the laser led, optics, focus and aiming though...
« Last Edit: June 04, 2018, 02:48:11 am by BrianHG »
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Offline TrickyNekro

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Re: Wi-Charge Infrared Wireless Charging
« Reply #20 on: June 06, 2018, 01:06:26 am »
Man, I´ve already made a post for it down below same forum! |O

I do not think it´s a laser, I suspect something like a LED matrix through a planoconcave gallium arsenide lens.
The tracker shouldn´t be something more than a beacon mechanism, they target the receivers lighting up separate segments of the matrix.
The lens should also help with tracking, get fewer sense elements for larger area.

If you can see in the video, Linus is powering up at some point 2 trains and a speaker, multiple devices.
If they were not using a LED matrix and they were using a laser, they would just lose so much power output even with good and fast galvos.
Plus solar panels tend to get quite sensitive with shadows, a laser would only create a flat spot effectively making the rest of the panel look
like a shaded area.

Regards, Lefteris
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Offline StillTrying

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Re: Wi-Charge Infrared Wireless Charging
« Reply #21 on: June 06, 2018, 01:57:52 am »
Looking at the second half of this article, if they are using the right solar cell tuned to the laser diode, the solar cell will have close to 100% efficient power recovery:

If they were getting that efficiency I think they might have mentioned it!

I'd guesstimated it at 20-30% X 20-30% which = 6%.

The TX in the test video can power up to 4 clients / trains :), which sounds like 4 lasers, we still don't know how the finding of clients works, and I still don't know why any of the very intense IR doesn't appear on the video.
CML+  That took much longer than I thought it would.
 

Offline Cyberdragon

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Re: Wi-Charge Infrared Wireless Charging
« Reply #22 on: June 06, 2018, 05:29:54 am »
A lens filter of some sort maybe?
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Offline BrianHG

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Re: Wi-Charge Infrared Wireless Charging
« Reply #23 on: June 06, 2018, 05:47:09 pm »
They have come back and said that system efficiency is "greater than 5% and lower than 27%" (the 27% figure I got from assuming no capture area loss).
So, its 6%. Maybe 5.5% on a bad day. :)

My guess would be 10% if they can hit the target 100%
I wonder how well they track the trains in that demo. I need to get data on those trains, but you probably only have to hit a small percentage of the time with a high energy short pulse to keep the train going.
Something like a phone on a desk might need some sort of feedback to "dial in" the laser. i.e. it measures the solar cell energy output and feeds back that data as the beam hunts round.
Probably only when the line of sight is only perpendicular.  What do you think happens at sheer angles?
For a wireless system, no one will always be directly beneath the transmitter, especially when transmitting to 4 devices simultaneously, devices which may be hand-held.
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Offline texaspyro

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Re: Wi-Charge Infrared Wireless Charging
« Reply #24 on: June 08, 2018, 12:57:50 am »
All these efficiency calcs seem to ignore the power required by the scanner and control electronics.  Wanna bet those draw more than 1-5 watts?  That addition cuts the system efficiency down to nubbins.
 


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