Attaching a Generator to a Motor or Wheel

Many people believe they've discovered the way to fix all energy and transportation problems.

Their answer? Power an electric generator with an electric motor that are wired together!

The problem is, this simply does not work, even if a battery system is introduced, nothing will cause the motor to infinitely turn the generator.

Why you say? Well it's basic laws of physics.

Read the Wikipedia article on Perpetual Motion for more on the physics:
http://en.wikipedia.org/wiki/Perpetual_motion

You can never have an electrical or mechanical or thermal system which is more than 100% efficient, in fact, to date, you can not even have a system which is 100% efficient.

The energy inside of any closed system will find some way of escaping as another form of energy.

For example, electrical energy will escape a closed loop of wire (or a motor attached to a generator) by either turning into Magnetic energy or Heat energy from the electrical resistance.

This means you'd have to find some way of keeping the energy from converting into another form of energy inside your closed loop to have a 100% efficient system.

Even if you do achieve this 100% efficient system, there is still absolutely no way you can create more energy from this system, the energy must come from somewhere.

If you must completely isolate your closed system from everything to reach 100% efficiency, how would more energy find it's way into your 100% closed system?

Some people believe that Fusion power plants are Perpetual Motion machines, but unfortunately they are not.

In order for a Fusion Generator to run, you must keep introducing more Matter to convert into Energy, meaning you are not getting more power out of the system without placing some kind of fuel into it first.

In conclusion, there is no such thing as infinite energy system.

If some of this article boggles your mind, you may want to step back for a few minutes and read it again later.

Adding a Wind Generator to the Car

Another proposition given out has been adding a wind generator to the outside of the car. The idea being at high speeds the wind generator can generate electricity to power the car. This is also impossible. Here are a few examples why it won't work...

Let's say it takes 10,000 Watts to keep your car at 50 mph. And we're striving to maintain speed.

First example...
Say you put the wind generator attached to the outside of the car. Wind generators work by creating drag on free flowing air to convert the wind energy into rotational then into electrical. Thus the wind generator can't produce any more energy than the drag it creates on the air. So if you installed a 100% efficiency 1,000 Watt wind generator on your car, your car will then need 11,000 Watts of power to maintain speed. Your wind generator is supplying 1,000 Watts of that, so you're back to 10,000 Watts to maintain speed. Hence without even looking at efficiency losses, there is no gain.

Second example, slightly more complex...
Your car needs the 10,000 Watts to maintain speed because of the drag on the body and wheel friction. We'll just look at the drag on the body as at high speeds it is much larger than the wheel friction. Now imagine you removed the radiator under the hood as you don't need it for your electric car. Reason stands you could duct the air from your car's grill into a wind generator where your radiator once was.

Let's assume again everything is 100% efficient. The car is already suffering from drag because of the air being stopped under the hood so we'll say drag is the same with the wind generator, 10,000 Watts. Let's imagine you can fit a 1,000 Watt generator underneath the hood driven purely by the frontal area of the grill. With everything perfectly efficient, you will deliver 1,000 Watts additional to your motor, effectively decreasing your energy needs down to 9,000 Watts.

Sounds good right? Well in actuality there are inefficiencies. 95% loss from motor, 95% loss from controllers, 95% loss from transmission. 1,000 * .95 * .95 * .95 = 857 Watts. So now 10,000 - 857 = 9,143 Watts. Still better than nothing.

Now let's approach this differently. Instead of trying to harness the drag we're creating, let's try to get rid of it. Buy a $20 sheet of aluminum and place it over your grill. Your drag has reduced by 1,000 Watts, meaning your car only need 9,000 Watts to maintain speed. Much easier, simpler, and cheaper than a complex ducting/generator system.

Third example...
We've been assuming no external wind. Say like your car was parked with your wind generator running. It would generate power from the external wind and store it into the battery. You then bring in the generator to remove the drag and begin driving. That is completely doable and why many people install wind generators at their house (it'd be a pain in the butt to haul it around in the car).

Fourth example...
Given that the car needs 10kW to move at 50MPH, how big will the turbine be? Well, the Skystream 2.4kW turbine has a rotor width of 12ft (4m), and weighs 170lbs (77kgs). To get 10kW, you'll need 4-5 of these.

[Electra]

What a great explanation! Our club just finished showing our EVs at the local Sustainable Living Expo and I really needed a good answer to that question. I can't believe the number of people that ask that question.

Your explanation is perfect. Thank you.

[Ellrot]

Excuse me if I seem ignorant, I'm new to this

Couldn't you just use a wind generator to just charge the batteries whilst moving, to simply give a slightly longer range.

Paired with solar panels, could that make a small difference, surely every little helps...

[Sunking]

Originally Posted by Ellrot

Excuse me if I seem ignorant, I'm new to this

Couldn't you just use a wind generator to just charge the batteries whilst moving, to simply give a slightly longer range.

Paired with solar panels, could that make a small difference, surely every little helps...

Nope the extra drag created by the fan blades will use more energy than the turbine can produce thus giving a shorter range.

[Ellrot]

I'm not trying to argue with your logic, but has anyone tried this? I'd like to see the test results

[Sunking]

Originally Posted by Ellrot

I'm not trying to argue with your logic

Well it is not logic, it is physics law of Thermal Dynamics and Conservation of Energy. What it implies is above unity gain which is impossible. I do not know if anyone here has tried it or not, but I can tell you there are people who have tried, and will even sell you a book telling you how to do it. It is called a SCAM like HHO and Water-4-Gas.

As for solar panels has some merit, but debatable whether it is worth it or not. Solar panel efficiency ranges from 5% on the low end for lightweight flexible film, up to 20% for heavy rigid mono crystalline panels. That means for a 5% panel you can generate up to 50 watts/meter square at solar noon, up to 200 watts/meter square. Depending on where you live and time of year with 2 square meters of surface area you can generate anywhere from 75 watt hours per day on the low end up to 1200 watt hours on the high end. With a 400 wh/mile battery to wheel efficiency translates to 1/4 mile up to 3 miles extended range per day. IMHO not worth the added expense and extra weight.

[TX_Dj]

Originally Posted by Ellrot

I'm not trying to argue with your logic, but has anyone tried this? I'd like to see the test results

You can break the law, but you can't break the laws of physics.

There is no way that putting a generator, let's say it's about 80% efficient, into the wind stream is going to net you anything better than a 20% loss. The truth of the matter though is that the blades turning that generator aren't 100% efficient either, so the loss number will be even greater.

[Jason Lattimer]

Originally Posted by Ellrot

I'm not trying to argue with your logic, but has anyone tried this? I'd like to see the test results

Sure did here it is...........http://www.youtube.com/watch?v=bkcn8...next=1&index=4

[Beyonder]

There's to many variables in all of the statements. The amount of power solar panels could generate is dependant on your location....parking position, direction of travel,etc.

The use of wind generators not working is not entirely 100% correct either, it is correct that they increase drag, however consider the existing drag already there from your current radiator. You could utilize a pm gen there, this will NOT generate 100% and make your vehicle perpetual, however it will increase the overall efficiency a small fraction, by reclaiming energy already lost. This isn't saying slap a 10 KW turbine there, you would be looking at more along the times of 1kw at the absolute most, anything over that I believe would increase the drag to much creating an inefficiency as stated originally.

If you want to improve efficiency, look into thermoelectric modules ( like the ones in coolers ) these only generate about 10% (if memory serves) there capacity. A typical module should generate about 3 - 5 watts, giving you about 30ish per square foot, = 90 - 150 watts per square foot. These require temperatures of the extreme, therefor you would need to utilize the wasted energy from the EM. Waste on these is roughly 10 - 15%? somebody correct me if I'm wrong here. Figure out the waste @ 10% of a say 20HP ( 15KW ish ) motor, your recovery not counting any losses from thermal transfer would only by 1.5KW. So you could theoretically bump your efficiency up 10% or 20% by recovering energy, not to mention regenerative breaking,etc.

Also, the rating of 400W/mile isn't 100% accurate either, Each vehicle weighing much differently, etc will have different ratings. Lightweight body panels would help a little, however do you really want to get into an accident with fiberglass panels....lol, i sure dont.

Just my thaughts
Clarence

[JRoque]

hmm, how about making a giant wheel and attach it to the moon with a really, really long pipe. When the moon goes around the Earth, the wheel rolls and generates free electricity!!!

Ok in all seriousness, do not pursue that idea shown in the video link above. It's flawed from the start. You cannot get more energy out of your car than you put in. Sure, you can park your wind-farm-mobile facing the wind on a beach and charge your battery pack in a couple of days or roll it down a 45 deg incline and get a few watts back. But otherwise, it doesn't work. The drag created by the fan blades consume more energy than they generate.

BTW, the same goes for adding an alternator to your EV expecting to "recover" power. The alternator idea is great if you think of it as a DC-DC converter alternative. You probably already have an alternator in your donor car, it's relative efficient, it's already hooked up to your 12V system and it just needs to be driven. But it will always create more drag than generate power.

JR