Is it theoretically possible to power up a device wirelessly?

[T & P]

Apologies in advance for what must be a very dumb question to anyone with an ounce of knowledge on the subject... But seeing as we're already capable to transmit huge amounts of data by wi-fi, Bluetooth and other such wireless ways, I was wondering if it is theoretically possible to send power wirelessly as well to mobile devices...

 

[Fez909]

Yes. It's called inductive charging and the Nexus 4 (among other phones) have it.

 

[T & P]

Mmm... The potential is massive then, if we could achieve devices being able to stay powered indefinitely by feeding power off a wireless source... But I guess that would result massive wastage of power.

 

[weltweit]

An industrial company I worked with was doing this some years ago, it isn't difficult but the devices do have to be quite close to another.

 

[Crispy]

It works via magnets, so the charger and the receiver have to be as close as your typical household magnets do to feel an attraction, ie. very.

 

[ferrelhadley]

Many RFIDs use this.

 

[free spirit]

I'll happily admit that to me, wireless charging is akin to witch craft and something to be feared.

Sure I'll get my head around it one day and probably be installing it.. til then it's wires all the way for me

 

[Dexter Deadwood]

I am reminded of the dreadful tv series Falling Skies. I have a few episodes left to watch but have other things to do.

 

[TruXta]

Tesla/conspiracy/aliens.

 

[DotCommunist]

you can do it at distance but those invisible power rays are called 'microwaves' and they tend to cook portions of anyone who moves through the path of them

 

[gentlegreen]

My toothbrush does it.
By using higher than mains frequency it at least makes the inductors small and the separation distance manageable - doesn't stop it being a hugely inefficient transmission method.

 

[weltweit]

It works via magnets, so the charger and the receiver have to be as close as your typical household magnets do to feel an attraction, ie. very.

Pretty sure the industrial method I mentioned was just two large coils, one in the base and one in the device.

 

[Crispy]

So electromagnets then

 

[Citizen66]

Btw - power up tends to mean switch on so I was expecting to give a completely different answer.

I'm sure I read somewhere that the military are developing (or have developed?) a system where planes could be 'refueled' using lasers.

 

[Disjecta Membra]

Tesla/conspiracy/aliens.

Tesla did actually build the Wardenclyffe Tower, tho it was never fully operational, as people have said the idea was sound. Justly conspiracies abound imo, capitalist lightbulb conspiracy etc.

 

[Crispy]

The idea was sound, but wires are much better.

 

[Remus Harbank]

Tesla/conspiracy/aliens.

No. Tesla vs Edison. Edison won.

 

[gentlegreen]

No. Tesla vs Edison. Edison won.

No he didn't.

Edison's "brilliant" idea was to have a small coal-fired power station on every block supplying DC at the voltage required.

Tesla's AC allowed centralised power generation of high voltage AC for efficient transmission and easy conversion to lower voltages as needed.

Tesla's mistake was to give his system away to Westinghouse for the greater public good.

 

[ItWillNeverWork]

Edison's "brilliant" idea was to have a small coal-fired power station on every block supplying DC at the voltage required.

That's insane.

 

[gentlegreen]

That's insane.

I feel sure he must have realised very early on - but persisted with it - electrocuting elephants etc, to prove that AC was "too dangerous".

 

[gentlegreen]

Actually, I've just been refreshing what I thought I knew about Tesla and once you get the Serbian Nationalist / pseudo-scientific conspiranoid crap out of the way, it seems he just developed what was there before - like a good engineer. He'd first worked for Edison and then Westinghouse ...
He could have retired young and very comfortably in spite of losing out on a lot of royalties, but ploughed all his money into more and more fanciful projects.

 

[HAL9000]

if mobile phone companies can ever get this to work. It will be great for long standby times,

LONDON — Nokia has started demonstrating a prototype mobile phone that uses energy harvesting technology to recharge itself using only ambient radio waves - emitted from mobile antennas, TV masts and other sources.

The prototype has been developed at the Finnish group's Cambridge, England research laboratory.

Current prototypes can scavenge between 3 to 5 mW.

The short-term goal is to get in excess of 20 mW, enough power to keep a phone in standby mode indefinitely without having to recharge it. But this would not be enough to actually use the phone to make or receive a call. So ultimately the hope is to be able to harvest as much as 50 mW which would be sufficient to slowly recharge the battery.

http://www.eetimes.com/document.asp?doc_id=1253967

 

[gentlegreen]

There used to be a recurring discussion in "Practical Wireless"-type circles about whether "carrier-power" was actually theft ..

And urban myths about people living near BBC transmitters with suspiciously-large antenna arrays...

Personally I would love to steal as much power as possible from iPhones.

 

[ViolentPanda]

No. Tesla vs Edison. Edison won.

It was more that Edison's ideas served the existing corporate interests better than Tesla's did.

 

[ViolentPanda]

That's insane.

Not for the generating combines who'd have constructed and administrated the power stations, though.

 

[HAL9000]

That's insane.

Instead of coal fired power stations, you could have a small gas powered electrical power station in every home. Take a look at this

http://www.energysavingtrust.org.uk...ology/Micro-CHP-micro-combined-heat-and-power

Its an idea that's not taken off. But it could have an impact in the future if the costs are right.

Why would want your own power station?

1. Gas power stations only convert some where between 40% and 50% of the heat from gas combustion into electricity, the rest of the heat is thrown away.
   
2. Electrical transmission losses in getting that electricity to your home.

So there are opportunities for home generation and using any wasted heat to warm water for your home.

At a guess there will be a number of problems,

1. Home generation is unlikely to be as efficient as a large scale power station, but new technology could change this like thermophotovoltaic cells (http://en.wikipedia.org/wiki/Thermophotovoltaic)
2. Cost.

 

[gentlegreen]

I have dreams of building a woodgas-powered CHP unit.

Where it falls down with me is I have little use for the waste heat - I only have hot water once a week.
But I suppose I might appreciate it in old age - though by then I hope to have at least part of my home super-insulated.

 

[free spirit]

1. Gas power stations only convert some where between 40% and 50% of the heat from gas combustion into electricity, the rest of the heat is thrown away.

more like 60% for CCGT, which most are now.

 

[HAL9000]

more like 60% for CCGT, which most are now.

I didn't know about CCGT.

But lobby groups around micro power plants for the home still think it has a future. ( also known as micro chp, chp = combined heat and power)

Long term I think local power generation could have a future, its applying internet ideas to power generation. Traditional telephone systems had all the control functions in a central place, the internet moved most of the controls to the edges of the system.

Local power generation might be able to shift some of the power generation to the edge. Perhaps improving the efficiency of power generation and possibly making the system more robust.

But...... I believe current solar solutions for the home in the US do not work during a power failure. The reason for this is that the electricity company does not want their workers to get electrocuted by solar power systems when they try and repair a broken transmission line.

 

[hiccup]

Here's a guy doing a ted talk, demoing wireless electricity:

http://www.ted.com/talks/eric_giler_demos_wireless_electricity.html

(the actual demo starts at about 7 minutes)