lotta news about everything going wireless. but it's always just wireless data. and seeing that battery technology has been pretty stagnant for past decade and that future battery tech seems a ways off and not that great of impovement, i think that the next best solution would be wireless power. is it possible?
is wireless power possible?
- Thread starter ucjffj
- Start date
It's like I've always said, Tesla was WAY smarter than Einstein could ever hope to be. About midway through the article. But read the whole thing, its all interesting
Wasn't there are thread about this a few months ago?
The short answer is yes it is possible (laser/microwave beams) but unless you confine the energy to a narrow beam you can only use it to tranfer very small amounts of power; otherwise it becomes too inefficient and dangerous.
The short answer is yes it is possible (laser/microwave beams) but unless you confine the energy to a narrow beam you can only use it to tranfer very small amounts of power; otherwise it becomes too inefficient and dangerous.
Battery technology stagnant? Are you kidding? Batteries have taken off! Just look at lithium- everything is lithium now. NiCd and NiMH batteries have seen great increases in capacity per-unit, and charging methods have become much more advanced. Laptops from 10 years ago, some even 5 years ago were still using NiCd/NiMH batteries with poor life ratings. Now, there are LiPoly and LiIon batteries that last much longer, and are smaller to boot. I think that batteries have come a long way in the past 10 years.
Not to mention LiIon batteries tend to explode causing serious damage if improperly maintained... Imagine hte poor Vietnam soldiers who used the first gen ones way back when... ; ;
TuxDave
Lifer
- Oct 8, 2002
- 10,571
- 3
- 71
There's alot of work actually being done in this area. For very small devices.. I mean.. VERY SMALL, there's no room for a battery. As effective as LiIon and NiCd batteries are, they are still too bulky. Hence we get the term of energy scavenging where the device tries to gather as much energy from its surroundings. That amount of energy is not very large so the devices have to be carefully designed for minimal power consumption. So far the current application that I have heard of is with very small tranciever nodes that can recieve and retransmits whatever data while using only energy from the enviroment.
Nikola Tesla claimed that he could transmit power wirelessly (in 1899), by building a giant coil that would resonate and create a standing-wave pattern on the Earth. He claimed to have succeeded, but offered no real proof and never was able to demonstrate the effect for anyone. He gathered a lot of money and started building a 200 foot Tesla coil on Long Island, but after a few years, he lost backers and went bankrupt.
Tesla was a smart guy. He had a few years of college, which was more education than a lot of "inventors" of that era. You can see in his notes that he understood what an LC tank oscillator was. He was also a little confused about things, and stated that radio really worked by high-frequency conduction through the earth, not by electromagnetic waves.
He has a cult following who range from sensible admirers to total nuts who think he is still alive on the planet Venus, so be cautious when reading about him on the web. But he really was a very interesting scientist.
Tesla was a smart guy. He had a few years of college, which was more education than a lot of "inventors" of that era. You can see in his notes that he understood what an LC tank oscillator was. He was also a little confused about things, and stated that radio really worked by high-frequency conduction through the earth, not by electromagnetic waves.
He has a cult following who range from sensible admirers to total nuts who think he is still alive on the planet Venus, so be cautious when reading about him on the web. But he really was a very interesting scientist.
if you mean by wirelessly you mean by not making contact of course it is possible and I have even seen it done...
it is really quite simple.
(now this isn't really all that usable for the real world but it is possible)
what you need is an alternating current running throught a loop of wire that is wound up many times (aka a coil of wire)
This coil would create an induced alternating magnetic field.
That alternating magnetic field could be harnessed by placing another coil that is connected to whatever you want to power in the mag field. The inductance in the coil will cause a voltage across your load and voila you have wirelessly transmitted power. I have seen it done by using a lightbulb as a load.
ok now there are quite a few problems with this.
1. One of the most important problems... think of all those high power mag fields needed... might do a little damage to your computer... (just maybe
)
2. you have to have your device properly angled to maximize the mag field capture (not necessarily a prohibitive problem)
3. Probably the most important problem is power loss/decay. Lets suggest that the mag field is evenly distributed in all directions from a point (just for simplification). The power in the field can be realized in spheres around the point. The integration of the power availible at each point is equal to the area integral of the device coil over the area of the sphere at that point. in other words for the same size receptor you have a decay rate of 1/r^2 where r is the radius or distance from the transmit point. This would severely limit the power transmission capabilities.
This is the fundamental problem with all wireless transmissions (power, data, voice etc). This is also why there was a recent article on CNN talking about how our best bet to find other life might be through message in a bottle b/c of the decay rate of radio signals. As they go farther away the random interference of stellar noise will easily drown out the signals.
There are other possible ways like lasers but they would require a direct line of sight and could be a problem if the object was moved.
overall wireless power transfer can be done and probably will be done but for the near and probably middle future only over short distances.
(i am not stating that they would be done in the above way i was just showing that it could easily be done)
Josh
it is really quite simple.
(now this isn't really all that usable for the real world but it is possible)
what you need is an alternating current running throught a loop of wire that is wound up many times (aka a coil of wire)
This coil would create an induced alternating magnetic field.
That alternating magnetic field could be harnessed by placing another coil that is connected to whatever you want to power in the mag field. The inductance in the coil will cause a voltage across your load and voila you have wirelessly transmitted power. I have seen it done by using a lightbulb as a load.
ok now there are quite a few problems with this.
1. One of the most important problems... think of all those high power mag fields needed... might do a little damage to your computer... (just maybe
)2. you have to have your device properly angled to maximize the mag field capture (not necessarily a prohibitive problem)
3. Probably the most important problem is power loss/decay. Lets suggest that the mag field is evenly distributed in all directions from a point (just for simplification). The power in the field can be realized in spheres around the point. The integration of the power availible at each point is equal to the area integral of the device coil over the area of the sphere at that point. in other words for the same size receptor you have a decay rate of 1/r^2 where r is the radius or distance from the transmit point. This would severely limit the power transmission capabilities.
This is the fundamental problem with all wireless transmissions (power, data, voice etc). This is also why there was a recent article on CNN talking about how our best bet to find other life might be through message in a bottle b/c of the decay rate of radio signals. As they go farther away the random interference of stellar noise will easily drown out the signals.
There are other possible ways like lasers but they would require a direct line of sight and could be a problem if the object was moved.
overall wireless power transfer can be done and probably will be done but for the near and probably middle future only over short distances.
(i am not stating that they would be done in the above way i was just showing that it could easily be done)
Josh
For those seriously interested in an extrapolation of Tesla's work have a read of this site:
http://www.16pi2.com/index.htm
some very complicated maths and physics but very interesting reading.
http://www.16pi2.com/index.htm
some very complicated maths and physics but very interesting reading.
Anyone seen batery chargers that charge without any electrical contacts? Is that considered wireless? By electric toothbrush has a permanent, internal battery with no visible contacts, just a plastic case. To charge it you just set it in the platsic base that's plugged to the wall and it charges. I've seen other devices like this too. I always wondered how that worked. Is it wireless?
They use the induced coil method that SocrPlyr mentioned, there's a coil of wired in the base of the toothbrush and another in the plastic base which has an alternating current through it. Since they're right next to each other you can get enough power to charge it while not having a huge magnetic field.
As for methods of transmitting power, how about focused radio transmitter, could it be made efficient enough over smallish distances (10 meters r so)? Alternatively you could use higher frequencies that would travel further, but then you have problems with it being dangerous if anyone crossed the beam.
As for methods of transmitting power, how about focused radio transmitter, could it be made efficient enough over smallish distances (10 meters r so)? Alternatively you could use higher frequencies that would travel further, but then you have problems with it being dangerous if anyone crossed the beam.
i heard that with all the signals going around in the air (from radio and cell phones...) there is a method to use the energy stored in those signals in order to charge up batteries. it will also soon be possible to build a chip or something that doesn't have a battery on it. you send out a signal and the chip uses the energy in that signal to charge a capacitor which then powers the chip for a small time. pretty cool.
Jeff7
Lifer
- Jan 4, 2001
- 41,596
- 19
- 81
I've got some of the 1300mAH NiMH batteries from back when $3/battery was a good buy. Now there's 2250mAH for around $1.50 each.
Lithium Ion is nice too, though those batteries are a lot more complicated when it comes to charging them.
I'd be neat if there was some way of just confining electrons themselves. I tried the math awhile ago, based on the weight of an electron, and how many are in a coulumb; think it came to something like 50 megawatts in a pound of electrons. Something insane like that. Of course, it would be so dense that setting it on your hand, it'd just fall right through like the point of a super sharp needle. And it'd be dangerous - if the containment fails, you'd get a nice lightning bolt.
Yeah, it's realy just a transformer, with assembly required. A transformer is just two coils of wire - in the toothbrush's case, there's one in the base, and one in the toothbrush. Put them together, and you make the transformer complete.
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