Wireless Charging - Increased Accessibility and Convenience

Isn't wireless charging simply an isolation transformer, but with no iron core and frame physically bonding both sides together?

My toothbrushes charge in exactly the same way and have done for many years, before 2000 at least if I remember correctly....I am open to offers as to when such brushes were initially so charged as I haven't a clue...

So its nothing really new. Even Tesla was a proponent one could say and how long has he been dead?

Its also probably a lot less efficient than "wired" connections, but possibly less dangerous for some users...as well as getting rid of cables that could easily be damaged.

Also, it has been said that we already have too much environmental electrical "noise" for many years, some believe its dangerous to health, and these induction charging systems are not going to improve those noise levels are they!!!

Especially if they do not switch off automatically when no device needs to be charged!!!! They will increase the world's power requirements even further!!!

Now if they HAD to be Solar powered by law, I could get to like them!!!

So the technology has some pluses and minuses.....

Certainly, I have already enough "electrical noise" at home without adding to it!!! So not for me, at least until an affordable Solar version is sold!!

As I understand it the significant difference between a conventional isolation transformer and the wireless charger setup is that in the latter the primary and secondary coils are both part of resonant circuits, which makes the transfer of energy possible even over substantial air gaps.

Even so, you have to ask yourself why for well over a hundred years, why we have used iron (usually) to "link the primary to the secondary".....have we been wasting our time (and iron!) in doing this?

I think not, so no matter how we do it wirelessly, its still going to be "lossy".

A good website comparing both methods would be great....

I found a very biased opinion is here, take it with a pinch of salt!:-

wireless power consortium

It appears that as long as extra electronics is built in to stop charging wirelessly when the battery is full, when compared to wired chargers that have no shutoff (who bought that one??), then they are about the same in efficiency....

But I personally do not like any charger that does not know when enough is enough, which is partly why I design my own chargers......I do not like wasting (my) power.

So if you compare unlike with like, you come out about even....

There are other sites easily found with varying opinions.....but DO read between the lines.

Have fun!!

you have to ask yourself why for well over a hundred years, why we have used iron (usually) to "link the primary to the secondary"
Indeed. I seem to remember steam trains and valve radios dominating the same epoch. Who needs progress anyway?

We may not be using steam trains anymore, or valves in radios but electricity is here to stay (for a bit longer anyway!)....your comparison does not work well I feel......

Even transformers, the point I was trying to make, have only been refined since Faraday first made one in the 1830s?

Electromagnetic induction, the principle of the operation of the transformer, was discovered independently by Michael Faraday in 1831 and Joseph Henry in 1832.^[94] Also, Faraday was the first to publish the results of his experiments and thus receive credit for the discovery.^[95][96] The relationship between EMF and magnetic flux is an equation now known as Faraday's law of induction:

.

These following here are also not quite good comparisons either, but no worse than yours:-

Water is (hopefully) here to stay and we have been drinking Dinosaur piss for millions of years! Have you something better? (Don't say Beer, its mostly water!)

Air is here to stay, or do you have a better suggestion....

Electricity, and I see nothing to replace it yet, is, as I said before, a fundamental part of this world until all the energy is gone and we are back in the stone age!!

Try again.

I think you forget that electricity was used to activate the valves in the radios in the first place, until we found that transistors were a better use of the same electricity. We are still using electricity to charge battery-operated devices, but some engineers have now found that wireless charging, on a scale beyond your toothbrush, is now becoming practical:

Meet the Plugless L2 - wireless EV charging is the new normal.

Given the choice of plugging a cable into my electric car or running it over a pad, I know which I would prefer.

Being able to do something, is not the same as saying its good to do......

I see just further problems with more electrical noise.

Comparing it to tubes invented around 100 years ago is not clever.......

Being able to do something, is not the same as saying its good to do...... How true. I expect you said that when they introduced those new-fangled preset buttons on your valve radios. What's wrong with a big tuning dial knob and lots of station names, after all?

Your arguments are just that, arguments. Your comparisons are not!!

I have a different opinion, its mine and I would like to keep it and not continue argue with some school kid ideas.....

OK?

We must divide this into two catagories.

INDUCTIVE CHARGING. This is usually done in close proximity between the charger and the item charged. Generally the closer the more efficient and the further apart the less efficient. This is due to the fact that it uses magnetism as the means to move energy the same way a transformer does except that the coils are separated. Iron cores generally raise efficiency because it can be used to direct the magnetic field. Basic understanding of AC magnetic fields is all that is needed to be able to build a model. I have seen 3rd grade science fair projects that have done this.

WIRELESS REMOTE CHARGING. This is newer technology and can be done, but at what risk and cost. VERY inefficient. We used to transmit radio and TV signals at very high power so the old receivers could pick them up. Some people complained about being able to detect when the transmitters were turned on. People close to the stations would complain of lightbulbs glowing dimly when the stations transmitted. To transfer power at any distance the amount of energy required would be significant and the amount of power lost would be immense. Still there are people experimenting with this. There are PHD physicists in my town that have government grants to do so. If you think about it, this is very similar to the ideas for tying solar stations in space to the earth without wires. Personally I think it is a fruitless search and except in a few isolated cases basically useless, and a waste of monetary and intellectual resources. I also see some significant safety risks involved with this.

I have to agree with you on all fronts.

Alone the electrical environmental noise........

As I understand it, this is more than just inductive charging. It comes with a twist of resonance to improve the efficiency. From here:

Resonant Coupling

Eberhard Waffenschmidt, Philips Research

From the beginning of inductive power transmission, resonant circuits are used to enhance the inductive power transmission. Already Nicola Tesla used resonances in his first experiments about inductive power transmission more than hundred years ago. Especially for systems with a low coupling factor, a resonant receiver can improve the power transfer. Resonant power transmission is a special, but widely used method of inductive power transmission and is limited by the same constraints of magnetic fields emissions and efficiency.
To understand the effect, it can be compared to mechanical resonances. Consider a string tuned to a certain tone as mechanical resonator. Even a far away and low level sound generator can excite the string to vibration, if the tone pitch is matched.

Here, the resonator in the receiver consists of the receiver inductance and a capacitor. Also the transmitter can have a resonator. The general arrangement is illustrated in Figure 6a. The transmitter and receiver coils LTx and LRx can be considered as weakly coupled transformer. For this, an equivalent circuit diagram consisting of magnetizing and stray inductance can be derived, as shown in 6b. In this diagram, also the resistances of the windings are shown. The diagram shows clearly, that the resonant capacitors cancel out the stray inductance in the receiver and the magnetizing inductance in the transmitter. Now, the only remaining limit for the power transmission is the winding resistances of the coils, which impedance is one or two orders of magnitude lower than that of the inductances. Therefore, for a given generator source, much more power can be received.