Making EVs BETTER than traditional cars

[dcb]

re: 1 yup, useful wireless. most wireless keyboards are permanently parked, within a couple feet of the cpu.

re 2: +1, I had a fancy reel mower but managed to break it.

[NiHaoMike]

Originally Posted by dcb

A typical high power AM station putts out 50000 watts, or 67 horsepower, that is radiating out in three dimensions. The power available to a given sized antenna (say car sized) is a rapidly decreasing fraction of that as you get farther from the transmitter.

If I figure it right (no promises) a saturn sw2 sized rectangle could at most see 1%. or 0.7 hp at 17 feet from the antenna! It gets worse at an accelerating rate the farther you get.

I mean the inefficiencies are obvious, right? We aren't seriously considering wireless en-mass for powering vehicles, for convenience, are we?

It doesn't quite work that way with resonant circuits.
Nikola Tesla Page, Tesla's power receiver
You'll need superconductors (very high Q) to get useful amounts of power, but if that is solved, then it's possible to build a car that can charge from radio waves.

[dcb]

well superconductors are not exactly new, has anyone actually tried it? Even if they do solve room temperature superconductors (or an antenna in a thermos?) does it make wireless powering of a car efficient? i.e. within a percentage of a wired connection (assuming we get to use superconductors in the grid too)?

Or are there some other assumptions going on here that are not obvious?

[Christ]

I also use my 37" TV as a computer from across the room, which makes a wireless keyboard nice.

I have, however, decided that I will probably make a dummy battery with an inverter so I can plug it into the wall next to my couch, which is more economical than even rechargeable batteries. Frankly, it's not that I care if it's wireless, just that with a 1 year old boy running around, I'd rather not have cords draped across the living room, especially considering his penchant for grabbing all things electrically related and cord sized/shaped.

For the most part, we use the laptop, which is basically a home computer at this point, since the "top o the line" battery only lasts about 20 minutes under idle conditions. It stays plugged in at all times.

Regarding the mower, well, I see no problem with using a reel mower. I did it for 3 years in conditions ranging from crab grass to alfalfa/timothy grass and even a bunch of nettles and thistle in between. It's not really as hard as people think it is, once you get used to walking with your back straight. It really does train posture, though. You can seriously hurt yourself if you don't use them properly. Mine's a little worn out at this point, and could use new wood handles, etc. but the blades will sharpen with the first use of the season.

[NiHaoMike]

Originally Posted by dcb

well superconductors are not exactly new, has anyone actually tried it? Even if they do solve room temperature superconductors (or an antenna in a thermos?) does it make wireless powering of a car efficient? i.e. within a percentage of a wired connection (assuming we get to use superconductors in the grid too)?

Or are there some other assumptions going on here that are not obvious?

The main point is to recover some energy that is currently being wasted.

[Christ]

Originally Posted by NiHaoMike

The main point is to recover some energy that is currently being wasted.

Microwaves from space!!!!

[dcb]

meh, I don't know if collecting more sun and focusing it on the earth is gonna go over so well with the environment crowd. Or the arguably un-paranoid "don't point that at me" crowd.

re: recover energy, we could turn off most them towers and problem solved really that transmitter energy is a drop in the baltic sea. If you are saying lets crank up the transmitters I'm saying let's not cus it isn't efficient.

[NiHaoMike]

Originally Posted by dcb

re: recover energy, we could turn off most them towers and problem solved really that transmitter energy is a drop in the baltic sea. If you are saying lets crank up the transmitters I'm saying let's not cus it isn't efficient.

It would be easier to develop practical superconductors than it is to shut down most of the transmitters. And using existing infrastructure with wireless power simplifies implementation in the real world.

And on the note of using EVs as mobile power supplies, a friend of mine has thought about it almost 2 years ago!
design exercise: inverter for Toyota Prius - diyAudio

For a little design exercise, design a large power inverter for a Toyota Prius. Some possible applications include allowing the Prius to double as an emergency generator, allow it to be used as a mobile power supply, etc. The following conditions apply:
1: Input is the 200v battery pack.
2: Output is 120v and/or 240v AC of at least 1kw (preferably 3kw or more) 60Hz sinewave.
3: The inverter must stay within regulation over the entire range of battery voltage.
4: The inverter should only power up when the car is on and ready to run the engine as needed.
5: The design will *NOT* actually be built. It is only a design exercise.

My thoughts:
* 200v is a good amount over the 170v peak of 120v AC, but I'm not sure how low it goes. If it doesn't go too low, a filtered H bridge should be enough for 120v. For 240v, a means to boost the voltage would be needed.
* The fact that a car would almost always be used on a more regular basis than a standalone generator means that problems would be caught earlier than with standalone generators. It's not uncommon for a standalone generator to break down unknowingly until the moment it is actually needed. In addition, the high power rating and very high peak rating would avoid issues when running large loads like central A/C or large commercial refrigeration.
* The idea can be extended. Think of a Prius as a very powerful mobile power supply and lots of ideas pop up. Businesses in particular might like the idea of being able to use something like a powerful arc welder without access to power.

Once again, it is only a design exercise and will *NOT* actually be built.

It could also be useful for large alternative energy systems with high voltage batteries. Or with a few adaptations, it can be used as a VFD for a motor.

[dcb]

Originally Posted by NiHaoMike

It would be easier to develop practical superconductors than it is to shut down most of the transmitters.

Wow, easier to develop superconductors than to pull the plug on the inefficient thing?!? We have a serious disconnect here Mike I guess I have been making the assumption that efficiency of the system as a whole was on your radar, maybe that isn't correct? Even with(if) superconducting antennas, given the average distance to AM towers, how efficient do you expect this to be?

Originally Posted by NiHaoMike

And on the note of using EVs as mobile power supplies

Using a prius to make electricity is flawed from an energy saving perspective, as whatever energy you "put back in the wall" will come from gasoline.

But people do use them as "emergency generators" of a sort, have been for years. But whoopie, I have an inverter that runs off a 12 volt battery too, and a $30 garage sale generator, and lots of 12 volt appliances (and a 12 volt solar panel). I wouldn't encourage gasoline generation for anything but an emergency.

[NiHaoMike]

Originally Posted by dcb

Wow, easier to develop superconductors than to pull the plug on the inefficient thing?!? We have a serious disconnect here Mike I guess I have been making the assumption that efficiency of the system as a whole was on your radar, maybe that isn't correct? Even with(if) superconducting antennas, given the average distance to AM towers, how efficient do you expect this to be?

Since we're not recovering any significant amount right now, the current efficiency is roughly zero. The radio transmitters are already out there. Assuming we cannot shut them down, even 1% is a big improvement over 0%. Superconductors inherently have zero resistance, so efficiency will be determined by the efficiency of the rectifier and the energy used by the support equipment to keep the superconductors operating. At AM radio frequencies, 90% or more rectifier efficiency is not unreasonable. Room temperature superconductors would not need any support equipment to operate.