Author Topic: Wi-Charge Infrared Wireless Charging  (Read 5401 times)

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Online Marco

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Re: Wi-Charge Infrared Wireless Charging
« Reply #25 on: June 08, 2018, 01:02:59 pm »
So now we know it's a laser, it pretty much has to be 1450nm ... lower and it fries your retina, higher and it fries your cornea, of course putting a couple watt inside your eyeball still isn't healthy but better than the alternatives. That's probably 1000$ worth of laser diode in there.
 

Offline BrianHG

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Re: Wi-Charge Infrared Wireless Charging
« Reply #26 on: June 09, 2018, 02:08:00 am »
That's probably 1000$ worth of laser diode in there.
Less than 300$ if they buy 1 as a time.
Less than half that in quantity.
Even less if they buy the laser die bar or chip and mount the chip on their own heatsink.
Even less if they don't need communication grade stability and uniformity along the entire laser die bar.  (Sort of like accepting the B-Grade rejects as for optical power delivery charging, a 1 or 2 defective elements on the laser bar die is still acceptable.)
My guess is that they are paying around 50$ for their laser once they build in quantity.  Any more and their product will be economically unviable except for the super rich.
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Online Marco

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Re: Wi-Charge Infrared Wireless Charging
« Reply #27 on: June 09, 2018, 03:20:34 am »
These aren't communication diodes, nor are bars convenient.

PS. well not fibre optic communication diodes at any rate, free space optic communication maybe ... but that's a lot more boutique.
« Last Edit: June 09, 2018, 03:22:56 am by Marco »
 

Offline StillTrying

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Re: Wi-Charge Infrared Wireless Charging
« Reply #28 on: June 09, 2018, 04:04:54 am »
it pretty much has to be 1450nm ... lower and it fries your retina, higher and it fries your cornea, of course putting a couple watt inside your eyeball still isn't healthy but better than the alternatives.

Normal digital cameras and videos seem to stretch to only 1100nm-1200nm, could that be why there's no sign of the laser dot in the videos.
 

Offline ConKbot

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Re: Wi-Charge Infrared Wireless Charging
« Reply #29 on: June 12, 2018, 08:06:12 am »
it pretty much has to be 1450nm ... lower and it fries your retina, higher and it fries your cornea, of course putting a couple watt inside your eyeball still isn't healthy but better than the alternatives.

Normal digital cameras and videos seem to stretch to only 1100nm-1200nm, could that be why there's no sign of the laser dot in the videos.
That and Id expect the RED camera that LTT use for studio work to have a very good IR cut filter. You can't have a pro camera with purple halos around flames and live effects.
 

Offline StillTrying

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Re: Wi-Charge Infrared Wireless Charging
« Reply #30 on: September 05, 2018, 08:13:33 pm »
If this thing really was as good as in the Linus video, safe, approved, efficient, miles ahead of ubeam, they wouldn't still be begging for partners.
www.wi-charge.com/press/wi-charge-6-months-of-industry-recognition-in-review/
 

Offline Cyberdragon

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Re: Wi-Charge Infrared Wireless Charging
« Reply #31 on: September 06, 2018, 01:12:40 am »
It is better than Ubean, since it actually works. But it is still super ineffecient and worthless.
*BZZZZZZAAAAAP*
Voltamort strikes again!
Explodingus - someone who frequently causes accidental explosions
 

Offline StillTrying

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Re: Wi-Charge Infrared Wireless Charging
« Reply #32 on: November 04, 2018, 07:14:34 am »
 

Offline Domagoj T

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Re: Wi-Charge Infrared Wireless Charging
« Reply #33 on: November 04, 2018, 07:29:08 am »
Efficiency 20%.
https://twitter.com/TheChargeGuy/status/1057298664316694529
Don't they use solar panels for the receiver? How are they getting 20% if most panels themselves are roughly there? Are they using something cutting edge? Does it fall under the concentrated PV umbrella? But even those are only around 30-40%.
Hmm
 

Online Marco

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Re: Wi-Charge Infrared Wireless Charging
« Reply #34 on: November 04, 2018, 07:55:41 am »
I wonder if they'll have to use a very bright white light in addition to the laser to trigger blink reflex.
 

Offline StillTrying

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Re: Wi-Charge Infrared Wireless Charging
« Reply #35 on: November 05, 2018, 02:03:59 am »
Don't they use solar panels for the receiver? How are they getting 20% if most panels themselves are roughly there? Are they using something cutting edge? Does it fall under the concentrated PV umbrella? But even those are only around 30-40%.
Hmm

As a very first guesstimate of the power efficiency from emitter and receiver I usually go for 30% X 30% which is only 9%, doubling the efficiency of one of them still isn't enough to get 20%.
They claim all the energy is in a very narrow IR beam, so it's well into the CPV density levels and needing very special PV cells, I don't think they've mentioned that!
They claim 100% link efficiency, but ~50% of the intensity would be lost just getting through the IR cover.

The figures/guesstimates don't add up, I think it's mostly fake, following in the wake of uBeen.
 

Offline Domagoj T

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Re: Wi-Charge Infrared Wireless Charging
« Reply #36 on: November 05, 2018, 04:29:22 am »
The figures/guesstimates don't add up, I think it's mostly fake, following in the wake of uBeen.
Exactly. It doesn't pass the sniff test.
 

Online Marco

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Re: Wi-Charge Infrared Wireless Charging
« Reply #37 on: November 05, 2018, 04:46:36 am »
Efficiency for solar radiation isn't the same as efficiency for a laser.

PS. that doesn't necessarily make the link estimate realistic, but Domagoj T said the cell state of the art was 20%, which it isn't in this niche.
« Last Edit: November 05, 2018, 04:51:31 am by Marco »
 

Offline Domagoj T

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Re: Wi-Charge Infrared Wireless Charging
« Reply #38 on: November 05, 2018, 05:02:10 am »
PS. that doesn't necessarily make the link estimate realistic, but Domagoj T said the cell state of the art was 20%, which it isn't in this niche.
Not quite what I said, but doesn't matter.

This abstract
https://ieeexplore.ieee.org/document/4922910?arnumber=4922910
says the best they achieved with lasers and solar panels was 53,4%, which is still not enough to reach 20% when we take into consideration the efficiency of lasers.
 

Online Marco

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Re: Wi-Charge Infrared Wireless Charging
« Reply #39 on: November 05, 2018, 05:34:59 am »
With a 35% efficiency laser (page 3) you can almost get to 20% with no further losses. This is COTS, though not commodity.
 

Online SiliconWizard

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Re: Wi-Charge Infrared Wireless Charging
« Reply #40 on: November 06, 2018, 01:34:25 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.

What if the IR "dot" accidentally gets onto your eyes? Is that safe?
 

Online Marco

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Re: Wi-Charge Infrared Wireless Charging
« Reply #41 on: November 06, 2018, 01:58:58 am »
Eye safe lasers won't immediately destroy anything, because they dump power inside the volume of your eye rather than the 2D surfaces of the retina or cornea, but it's probably enough power to do damage to the lens quite quickly.

That's why I theorized about the bright white light, a blink reflex might be sufficient to make it safe.
 

Offline Domagoj T

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Re: Wi-Charge Infrared Wireless Charging
« Reply #42 on: November 07, 2018, 05:02:11 am »
With a 35% efficiency laser (page 3) you can almost get to 20% with no further losses. This is COTS, though not commodity.

Add two SMPS (one on transmitter side, one on receiver) with a generous 97% efficiency and you're at 17,5%, which is not 20%.
But all that is assuming they are using the perfect laboratory condition 53,4% efficient panels. I am hesitant to assume that.

They claim near 100% link efficiency, which I am interpreting that (nearly) all the energy that leaves the laser hits the solar panel. I may be wrong, but I would guess that a laser dot is circular, while solar panels shown in Linus Tech Tips video are rectangular. It follows that the laser dot does not cover the entire surface of the panel. My question is how does this affect the power generation when we know that, with standard solar panels, partial shade disproportionately reduces panel power?
 

Online Marco

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Re: Wi-Charge Infrared Wireless Charging
« Reply #43 on: November 07, 2018, 05:07:07 am »
Sectioned panels with diodes help a lot and given the power density you can make the sections quite small in this case. If you make it custom you could even have active circuits selecting the lit sections.
 


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