6 ms·

Wireless electricity? It's here

45 points by uladzislau 13y ago

quesera 13y ago
> Dr. Hall, CTO WiTriCity: > "We just don't think about it anymore: I'm going to drive my car home and I'm never going to have to go to the gas station and I'm never going to have to plug it in. Count me as a wireless electricity skeptic, in general. But this claim is astounding to me. I believe that if you placed a properly resonant circuit into an MRI device, for example, you could charge a decent sized battery (but probably not a vehicle propulsion battery) at a reasonable rate. But it would be horribly inefficient and your car (and everything else in your garage) shouldn't be made of ferrous metal. Cell phone batteries on little charger pads, sure. Maybe even via ambient EM, though I'm not convinced you could get regulatory approval above a certain emissions level (which, critically, has an inverse-square relationship to available current delivery capacity at the device). But the article also talks about lighting and televisions, and cars. WiTricity has investors to fluff, clearly, but is this not absolute crazy talk?
- IanCal 13y ago
  The claim on their wiki page was a light bulb at 90% efficiency at 3 feet. If it's more efficient when closer, you could put one in the bottom of your car and one just below the surface of your garage, and you'd probably only have a separation of about 1 foot. > But the article also talks about lighting and televisions, and cars. WiTricity has investors to fluff, clearly, but is this not absolute crazy talk? They've apparently already powered lighting, and the TED talk supposedly had them powering a TV [0] [0] http://www.ted.com/talks/eric_giler_demos_wireless_electricity http://www.ted.com/talks/eric_giler_demos_wireless_electrici...
  - quesera 13y ago
    Ok, sure. If you can control the proximity carefully, you can achieve reasonable efficiency. Transformers work. But it's still a super high powered magnet. There are more places than not where that's just a bad idea. Garages are high on that list. Also carports, kitchens, living spaces in general...offices, sleeping spaces..bathrooms. All bad. LED lighting gets you pretty far down the current draw curve, but I don't see a small, easily moved coil generating enough resonant current to be useful in many common consumer electronics. That coil has to be plugged in to the mains, remember -- invalidating the promise of wireless power, even at three feet. And ambient charging has all of those problems, squared.
    - thefreeman 13y ago
      Also, can't magnets interfere with pacemakers? "Oh, you have a pacemaker? Ya, don't come over or you will die... I don't want to have to plug in my lamps."
  - Stwerp 13y ago
    From what I've seen of their demos (going off memory), they focus on power transfer to a single device. Their efficiency drops to near 0% when multiple devices are being powered. I have a hard time getting excited about these guys' work, but will readily admit they are excellent about generating publicity. There is a lot of _very_ closely related work in resonant energy transfer and use of time reversal or lensing currently being looked at around academia. Hopefully one day it will pan out, but it is never going to be as efficient as running a wire. For some applications wireless power is a great enabling technology, but powering a light or a tv in your home? That's a hard sell for the "convenience" of moving your tv versus the extra costs in energy inefficiency.
- ivanca 13y ago
  For cars is way more feasible just having two electrical-charged metal bars that always touch the underside of your car when is in the garage, and if they are far apart it's complete safe (i.e: children can't touch both at the same time)
  - Someone 13y ago
    Children may have pieces of metal such as bicycles, or they may walk across such bars while holding hands. I bet there are way more failure modes with such an approach (kids never drop buckets of water inside garages, for example) I would put in a few more safety methods.
    - ivanca 13y ago
      You can also have a 4 heavy switches under the 4 wheels, that way a very heavy object (the car) must be there over all of them to turn on the electricity.
      - mikeash 13y ago
        And then you spill some water while the car is parked in the garage and bam, 440V right across the heart.
        ivanca 13y ago
        Are you serious? To touch the car the metal bars must be above the floor, unless you spill tons of water enough to fill the garage you should be okay.
- tobiasu 13y ago
  This is one of the fastest electric race cars on earth right now: http://www.draysonracingtechnologies.com/home.html http://www.draysonracingtechnologies.com/home.html http://www.draysonracingfe.com/technology.html?Wireless-Charging-3 http://www.draysonracingfe.com/technology.html?Wireless-Char... It gets charged via induction. Fifth Gear recently had a segment about this where you could briefly see the black flat device they park it over. edit: pic: http://www.draysonracingfe.com/technology.html?Wireless-Charging-3 http://www.draysonracingfe.com/technology.html?Wireless-Char... Of all the silly things one could do with "wireless" electricity, charging cars is probably one of the better applications. I believe this is in use since quite some time for charging equipment like forklifts, busses on fixed lines, etc.
finishingmove 13y ago
No mention of Tesla (Nikola Tesla) in the whole article? ...
- andyzweb 13y ago
  media generally has a memory of ~9 months to a year at most
- iLoch 13y ago
  Shh this technology is new and was invented by an MIT professor.
- mchouza 13y ago
  He is the first author cited in their paper: http://www.witricity.com/pdfs/highly-resonant-power-transfer-kesler-witricity-2013.pdf http://www.witricity.com/pdfs/highly-resonant-power-transfer...
clarry 13y ago
I sure do look forward to getting rid of the mess of power cables on and behind my desk. A wireless dog leash would be nice too. But I'm not holding my breath. I'm also a little worried about efficiency.
- WiseWeasel 13y ago
  A wireless dog leash probably isn't too far off, for those who enjoy the means to upgrade their furry friend with a remote control brain implant.
daimyoyo 13y ago
It's been here for more than a century. http://en.wikipedia.org/wiki/Wireless_power http://en.wikipedia.org/wiki/Wireless_power
- mmphosis 13y ago
  http://en.wikipedia.org/wiki/Wardenclyffe_Tower http://en.wikipedia.org/wiki/Wardenclyffe_Tower http://theoatmeal.com/comics/tesla http://theoatmeal.com/comics/tesla
iLoch 13y ago
Couldn't this affect pacemakers, etc?
- Ygg2 13y ago
  I'd assume so, but it depends on pacemaker model, and the freq. WiTricity uses.
  - lostlogin 13y ago
    This is a very complicated problem. The length and orientation of the leads, type of pacemaker etc are all factors. And one mistake is one too many. This applies to a growing list of implants. Spinal cord stimulators, sacral nerve stimulators, deep brain stimulators, implantable defibs, cochlear implants, some hearing aids. Its a very long list. The possible complications are not just possible induced currents, but also heating. Many of the problems are covered here (although with MRI in mind) http://www.mrisafety.com http://www.mrisafety.com. It's a great resource but is absolutely terrible to use and everything takes 20x longer than it should to find.
tehwalrus 13y ago
> "Don't worry about getting zapped: Hall assures that the magnetic fields used to transfer energy are "perfectly safe" -- in fact, they are the same kind of fields used in Wi-Fi routers." LOL. power transmitted by a Wifi router ~= mW. Power required for, even a low energy light bulb ~= 10W. The current draw in modern homes is so big that EM transmission, especially at sensitive wavelengths like microwaves, is highly likely to cook things (and people). They may well have found a real way to make it work. But saying "it's the same as wifi" shouldn't convince anyone.
- squintychino 13y ago
  The common type of bulbs in a few years will be led lights. How much power does an led light bulb draw? Certainly less than 10W I'm guessing.
  - dharma1 13y ago
    typically 4-10W (home use)
  - ChuckMcM 13y ago
    True, but its remarkable how constant the amount of electricity the 'typical' home draws, even as the things in it draw less. Things like the TV went from several hundred watts to only a couple of hundred, and then we added a home computer. I agree with the grandparent that you're not going to send a few kW of power into a house like this. The other aspect that wireless power folks face is that any conductor now has a much more serious voltage potential on it. This can cause weird things to happen when dissimilar metals are suddenly energized. Electro transport can cause otherwise strong welds/connections to vanish.
  - nickloewen 13y ago
    Unfortunately, that was the LED lightbulb wattage. http://www.homedepot.ca/product/9-watt-60w-daylight-led-light-bulb-1-pack/827149 http://www.homedepot.ca/product/9-watt-60w-daylight-led-ligh...
  - mnem 13y ago
shakeel_mohamed 13y ago
I want this so bad, mainly just for laptops and phones
kirk21 13y ago
It is just not efficient enough. You lose a lot of energy. JB Straubel commented that Tesla was looking into smart conductive charging is going to win out. Read more at http://evobsession.com/tesla-elon-musk-townhall-meeting-amsterdam-56-minute-video/#EPpeC060WhPrF3tB.99 http://evobsession.com/tesla-elon-musk-townhall-meeting-amst...
Ygg2 13y ago
Couldn't the wireless signal used to transmit energy be used to transmit data as well? Anyway without a solid power source WiTricity would seem to be kinda non applicable for larger areas, but it's still good enough for small home chargers and stuff. From what I remember about Tesla claiming that he would either use the ionosphere as a way to either amplify or bounce the signal. It's hard to separate fact from fiction with that man.
drakaal 13y ago
This isn't new. A "crysal" radio works the same way. http://www.instructables.com/id/Build-an-antique-style-crystal-radio/ http://www.instructables.com/id/Build-an-antique-style-cryst... You can use a Crystal radio to power an LED, or a lot of things, the stronger the RF source, the more power you can extract. The problem is they aren't efficient if you are using them as a power source. When you are pulling "free" energy out of the airwaves they are cool, all that wasted AM band, but if you are broadcasting just to power your cell phone they are about .1% efficient. That's not a very eco-friendly.
adrusi 13y ago
This looks interesting, but the conjectures people are making about pcell (the frontrunner for 5G cellular) being used for wireless power describe a more attractive solution. They would provide power only to the area of space where the receiver is which first and foremost makes it inherently safer than a system which doesn't focus the power. I'm not going to claim I know much on the topic, but intuitively it would seem that the ambient power produced by the pcell transmitters would scale logarithmically with the power being transmitted. But I trust that Witricity's produce is safe for most people since these things are highly regulated for safety. Perhaps more important to adoption is that the nature of Witricity's technology makes it impossible to selectively transmit power. Therefore, it would be impractical to charge a fee for using a power source. Pcell can do this, because it has to to be useful as a cellular technology. I don't see a world where electric cars are charge wirelessly by beacons on roadsides, not at current electricity prices and the loss that would be involved, but I can imagine low power devices such phones and laptops becoming much more elegant through wireless power.
chrismcb 13y ago
Isn't this only about 100 years late?
almosnow 13y ago
Sounds cool, but say goodbye to your credit cards or your hard drives.

45 points by uladzislau 13y ago

> Dr. Hall, CTO WiTriCity: > "We just don't think about it anymore: I'm going to drive my car home and I'm never going to have to go to the gas station and I'm never going to have to plug it in. Count me as a wireless electricity skeptic, in general. But this claim is astounding to me. I believe that if you placed a properly resonant circuit into an MRI device, for example, you could charge a decent sized battery (but probably not a vehicle propulsion battery) at a reasonable rate. But it would be horribly inefficient and your car (and everything else in your garage) shouldn't be made of ferrous metal. Cell phone batteries on little charger pads, sure. Maybe even via ambient EM, though I'm not convinced you could get regulatory approval above a certain emissions level (which, critically, has an inverse-square relationship to available current delivery capacity at the device). But the article also talks about lighting and televisions, and cars. WiTricity has investors to fluff, clearly, but is this not absolute crazy talk?

IanCal 13y ago
The claim on their wiki page was a light bulb at 90% efficiency at 3 feet. If it's more efficient when closer, you could put one in the bottom of your car and one just below the surface of your garage, and you'd probably only have a separation of about 1 foot. > But the article also talks about lighting and televisions, and cars. WiTricity has investors to fluff, clearly, but is this not absolute crazy talk? They've apparently already powered lighting, and the TED talk supposedly had them powering a TV [0] [0] http://www.ted.com/talks/eric_giler_demos_wireless_electricity http://www.ted.com/talks/eric_giler_demos_wireless_electrici...
- quesera 13y ago
  Ok, sure. If you can control the proximity carefully, you can achieve reasonable efficiency. Transformers work. But it's still a super high powered magnet. There are more places than not where that's just a bad idea. Garages are high on that list. Also carports, kitchens, living spaces in general...offices, sleeping spaces..bathrooms. All bad. LED lighting gets you pretty far down the current draw curve, but I don't see a small, easily moved coil generating enough resonant current to be useful in many common consumer electronics. That coil has to be plugged in to the mains, remember -- invalidating the promise of wireless power, even at three feet. And ambient charging has all of those problems, squared.
  - thefreeman 13y ago
    Also, can't magnets interfere with pacemakers? "Oh, you have a pacemaker? Ya, don't come over or you will die... I don't want to have to plug in my lamps."
- Stwerp 13y ago
  From what I've seen of their demos (going off memory), they focus on power transfer to a single device. Their efficiency drops to near 0% when multiple devices are being powered. I have a hard time getting excited about these guys' work, but will readily admit they are excellent about generating publicity. There is a lot of _very_ closely related work in resonant energy transfer and use of time reversal or lensing currently being looked at around academia. Hopefully one day it will pan out, but it is never going to be as efficient as running a wire. For some applications wireless power is a great enabling technology, but powering a light or a tv in your home? That's a hard sell for the "convenience" of moving your tv versus the extra costs in energy inefficiency.
ivanca 13y ago
For cars is way more feasible just having two electrical-charged metal bars that always touch the underside of your car when is in the garage, and if they are far apart it's complete safe (i.e: children can't touch both at the same time)
- Someone 13y ago
  Children may have pieces of metal such as bicycles, or they may walk across such bars while holding hands. I bet there are way more failure modes with such an approach (kids never drop buckets of water inside garages, for example) I would put in a few more safety methods.
  - ivanca 13y ago
    You can also have a 4 heavy switches under the 4 wheels, that way a very heavy object (the car) must be there over all of them to turn on the electricity.
    - mikeash 13y ago
      And then you spill some water while the car is parked in the garage and bam, 440V right across the heart.
      - ivanca 13y ago
        Are you serious? To touch the car the metal bars must be above the floor, unless you spill tons of water enough to fill the garage you should be okay.
tobiasu 13y ago
This is one of the fastest electric race cars on earth right now: http://www.draysonracingtechnologies.com/home.html http://www.draysonracingtechnologies.com/home.html http://www.draysonracingfe.com/technology.html?Wireless-Charging-3 http://www.draysonracingfe.com/technology.html?Wireless-Char... It gets charged via induction. Fifth Gear recently had a segment about this where you could briefly see the black flat device they park it over. edit: pic: http://www.draysonracingfe.com/technology.html?Wireless-Charging-3 http://www.draysonracingfe.com/technology.html?Wireless-Char... Of all the silly things one could do with "wireless" electricity, charging cars is probably one of the better applications. I believe this is in use since quite some time for charging equipment like forklifts, busses on fixed lines, etc.

finishingmove 13y ago

No mention of Tesla (Nikola Tesla) in the whole article? ...

andyzweb 13y ago
media generally has a memory of ~9 months to a year at most
iLoch 13y ago
Shh this technology is new and was invented by an MIT professor.
mchouza 13y ago
He is the first author cited in their paper: http://www.witricity.com/pdfs/highly-resonant-power-transfer-kesler-witricity-2013.pdf http://www.witricity.com/pdfs/highly-resonant-power-transfer...

clarry 13y ago

I sure do look forward to getting rid of the mess of power cables on and behind my desk. A wireless dog leash would be nice too. But I'm not holding my breath. I'm also a little worried about efficiency.

WiseWeasel 13y ago
A wireless dog leash probably isn't too far off, for those who enjoy the means to upgrade their furry friend with a remote control brain implant.

daimyoyo 13y ago

It's been here for more than a century. http://en.wikipedia.org/wiki/Wireless_power http://en.wikipedia.org/wiki/Wireless_power

mmphosis 13y ago
http://en.wikipedia.org/wiki/Wardenclyffe_Tower http://en.wikipedia.org/wiki/Wardenclyffe_Tower http://theoatmeal.com/comics/tesla http://theoatmeal.com/comics/tesla

iLoch 13y ago

Couldn't this affect pacemakers, etc?

Ygg2 13y ago
I'd assume so, but it depends on pacemaker model, and the freq. WiTricity uses.
- lostlogin 13y ago
  This is a very complicated problem. The length and orientation of the leads, type of pacemaker etc are all factors. And one mistake is one too many. This applies to a growing list of implants. Spinal cord stimulators, sacral nerve stimulators, deep brain stimulators, implantable defibs, cochlear implants, some hearing aids. Its a very long list. The possible complications are not just possible induced currents, but also heating. Many of the problems are covered here (although with MRI in mind) http://www.mrisafety.com http://www.mrisafety.com. It's a great resource but is absolutely terrible to use and everything takes 20x longer than it should to find.

tehwalrus 13y ago

> "Don't worry about getting zapped: Hall assures that the magnetic fields used to transfer energy are "perfectly safe" -- in fact, they are the same kind of fields used in Wi-Fi routers." LOL. power transmitted by a Wifi router ~= mW. Power required for, even a low energy light bulb ~= 10W. The current draw in modern homes is so big that EM transmission, especially at sensitive wavelengths like microwaves, is highly likely to cook things (and people). They may well have found a real way to make it work. But saying "it's the same as wifi" shouldn't convince anyone.

squintychino 13y ago
The common type of bulbs in a few years will be led lights. How much power does an led light bulb draw? Certainly less than 10W I'm guessing.
- dharma1 13y ago
  typically 4-10W (home use)
- ChuckMcM 13y ago
  True, but its remarkable how constant the amount of electricity the 'typical' home draws, even as the things in it draw less. Things like the TV went from several hundred watts to only a couple of hundred, and then we added a home computer. I agree with the grandparent that you're not going to send a few kW of power into a house like this. The other aspect that wireless power folks face is that any conductor now has a much more serious voltage potential on it. This can cause weird things to happen when dissimilar metals are suddenly energized. Electro transport can cause otherwise strong welds/connections to vanish.
- nickloewen 13y ago
  Unfortunately, that was the LED lightbulb wattage. http://www.homedepot.ca/product/9-watt-60w-daylight-led-light-bulb-1-pack/827149 http://www.homedepot.ca/product/9-watt-60w-daylight-led-ligh...
- mnem 13y ago

shakeel_mohamed 13y ago

I want this so bad, mainly just for laptops and phones

kirk21 13y ago

It is just not efficient enough. You lose a lot of energy. JB Straubel commented that Tesla was looking into smart conductive charging is going to win out. Read more at http://evobsession.com/tesla-elon-musk-townhall-meeting-amsterdam-56-minute-video/#EPpeC060WhPrF3tB.99 http://evobsession.com/tesla-elon-musk-townhall-meeting-amst...

Ygg2 13y ago

Couldn't the wireless signal used to transmit energy be used to transmit data as well? Anyway without a solid power source WiTricity would seem to be kinda non applicable for larger areas, but it's still good enough for small home chargers and stuff. From what I remember about Tesla claiming that he would either use the ionosphere as a way to either amplify or bounce the signal. It's hard to separate fact from fiction with that man.

drakaal 13y ago

This isn't new. A "crysal" radio works the same way. http://www.instructables.com/id/Build-an-antique-style-crystal-radio/ http://www.instructables.com/id/Build-an-antique-style-cryst... You can use a Crystal radio to power an LED, or a lot of things, the stronger the RF source, the more power you can extract. The problem is they aren't efficient if you are using them as a power source. When you are pulling "free" energy out of the airwaves they are cool, all that wasted AM band, but if you are broadcasting just to power your cell phone they are about .1% efficient. That's not a very eco-friendly.

adrusi 13y ago

This looks interesting, but the conjectures people are making about pcell (the frontrunner for 5G cellular) being used for wireless power describe a more attractive solution. They would provide power only to the area of space where the receiver is which first and foremost makes it inherently safer than a system which doesn't focus the power. I'm not going to claim I know much on the topic, but intuitively it would seem that the ambient power produced by the pcell transmitters would scale logarithmically with the power being transmitted. But I trust that Witricity's produce is safe for most people since these things are highly regulated for safety. Perhaps more important to adoption is that the nature of Witricity's technology makes it impossible to selectively transmit power. Therefore, it would be impractical to charge a fee for using a power source. Pcell can do this, because it has to to be useful as a cellular technology. I don't see a world where electric cars are charge wirelessly by beacons on roadsides, not at current electricity prices and the loss that would be involved, but I can imagine low power devices such phones and laptops becoming much more elegant through wireless power.

chrismcb 13y ago

Isn't this only about 100 years late?

almosnow 13y ago

Sounds cool, but say goodbye to your credit cards or your hard drives.