How is this possible

[weressl]

That was my initial thought also, but after reading the references I posted earlier about how MIT transferred power over 2 meters at 60+% eff, and over 1 meter at 90% efficiency - due to 10mhz freq & tuned resonant coils, I have come to the conclusion that 6" is nothin' and no c0il dropping is likely required!

Yep, that is a lot of conversion equipment. I seem to recall that the MIT calcs only included the efficiency of the sending and receiving point, eg. the air-gap, not the efficiencies of the conversion equipment, which could be additional.

 

[K8MHZ]

That was my initial thought also, but after reading the references I posted earlier about how MIT transferred power over 2 meters at 60+% eff, and over 1 meter at 90% efficiency - due to 10mhz freq & tuned resonant coils, I have come to the conclusion that 6" is nothin' and no c0il dropping is likely required!

Do you have a link that supports the 10 MHz thing? And do you know if that is the frequency that the cars will be using?

The reason I ask is that 10 MHz is very close to the 30 meter ham radio band (10.10 to 10.15 MHz). Interfering with a licensed operator using that band is against the law, intentional or not. (That is the same for any band that requires a license, not just ham radio). If a complaint is made, the FCC will force the owner of the charging device to shut it off or face very, very large fines. I worked with the FCC on a case where a telephone system that had just been installed was interfering with a ham radio operator across the street. They sent in a field agent and basically told the owner of the phone (that just spent big bucks on it) he had so much time to fix it, get rid of it or else face a big fine and still have to get rid of it.

10 MHz is an HF frequency that can propagate via the ionosphere all over the world. Under the right atmospheric conditions, ham operators can talk thousands of miles on 30 meters using 5 watts or less.

This could be interesting.

 

[K8MHZ]

Another thing.....

WWV, the radio station that broadcasts time over the air from the NIST, uses 10 MHz as one of their frequencies. Besides being cool to listen to the exact time coming from an atomic clock on 5, 10 and 15 MHz, the 'atomic clocks' the we have in our homes and on our wrists use the signals from WWV to keep the clocks accurate.

 

[weressl]

Do you have a link that supports the 10 MHz thing? And do you know if that is the frequency that the cars will be using?

The reason I ask is that 10 MHz is very close to the 30 meter ham radio band (10.10 to 10.15 MHz). Interfering with a licensed operator using that band is against the law, intentional or not. (That is the same for any band that requires a license, not just ham radio). If a complaint is made, the FCC will force the owner of the charging device to shut it off or face very, very large fines. I worked with the FCC on a case where a telephone system that had just been installed was interfering with a ham radio operator across the street. They sent in a field agent and basically told the owner of the phone (that just spent big bucks on it) he had so much time to fix it, get rid of it or else face a big fine and still have to get rid of it.

10 MHz is an HF frequency that can propagate via the ionosphere all over the world. Under the right atmospheric conditions, ham operators can talk thousands of miles on 30 meters using 5 watts or less.

This could be interesting.

http://web.mit.edu/newsoffice/2006/wireless.html

 

[K8MHZ]

http://web.mit.edu/newsoffice/2006/wireless.html

Interesting.

The claim is that they are using 'non-radiative' electromagnetism. I am sure they are, but I doubt they have mitigated any possible interference problem.

Non-radiative EMF is what you get in the near field of any antenna. It's the far field that gives us radiative EMF that we can use for radio signals.

Now, I understand that 6 inches is well within the near field of a 30 meter signal, but there is life beyond 6". It's the far field radiation I am concerned about.

Time will tell. But I don't see how it's possible, shy of a Faraday cage, to keep all the EMF in the garage. Even if they only 'lose' 10 percent, that's enough to wreak havoc on radios many miles away. Or worse, your neighbor that has thousands of dollars worth of radio equipment rendered useless by your charger, leading to obvious disenchantment.

 

[mike_kilroy]

yes, from my studying the topic I see that they must be in the near field (less than 1/4 wave) to make it work.

K8mhz, the reference I gave had the 9.99mhz freq listed.

AC8V

 

[hillbilly1]

I know when they first talked about level 3 chargers, they were going to use "split" transformers, the paddle just snapped into a socket, with no physical voltage passing through the connection. Just using magnetism to create the voltage in the windings on the car side.

 

[mike_kilroy]

the old EV1 used this method so nothing new there.....

 

[hillbilly1]

the old EV1 used this method so nothing new there.....

Yeah, that was a couple of years ago when we first started doing chargers.