[gwrmarines]

So I was thinking about electric cars. I don't know very much about physics but I do know that perpetual motion defies the laws of physics. A while back I thought why not use an alternator to recharge the batteries while in use, but you lose some energy when you convert motion to electricity, and you lose some energy when you convert electricity to motion. The total amount of energy in the car can only decrease.

Now, correct me if I'm wrong but the batteries will last a bit longer right?

What if you put a windmill contraption on the front of the car connected to another alternator to charge the batteries, and perhaps another setup for a couple solar panels. Would this be possible?

 

[Bullets~n~Beans]

They have built experimental cars that have tried just about everything. I believe the major universities have an annual contest for the engineering students that use nothing but solar.

 

[grandpamonkeytoes]

If I recall some years ago the auto industry was making fun of those vehicles because they would weigh out fuel in grams and figured out to about 1000 mpg and so MIT took up the challenge and took a dodge durango 4x4 and when they were done it got about 200 mpg but it was bought up quick and hushed up

 

[ToeCutter]

Nobody here can answer with absolute certainty. Enter Aladdin's cave and make up your own mind.

www.rexresearch.com

 

[MikeK]

Solar would help, but you're limited by how large solar panels are for how little power they actually make. It might add enough distance to be noticeable, but not enough to be worth the cost.

As for a wind driven alternator, the wind drive will add load to the vehicle because of wind friction loss. It's not going to give back enough to make up for it's loss because no system is 100% efficient. Even if it was, all it would do is replace the extra energy it costed due to wind friction.

Solar is the only technology that doesn't cost much more than added weight.

 

[MikeK]

If I recall some years ago the auto industry was making fun of those vehicles because they would weigh out fuel in grams and figured out to about 1000 mpg and so MIT took up the challenge and took a dodge durango 4x4 and when they were done it got about 200 mpg but it was bought up quick and hushed up

Everytime they've come up with ultra high mileage vehicles as an exercise, it's all been based on ultra lightweight materials, expensive friction reducing technologies, and teeeeeeeeeeeeny underpower engines with just enough power to move the vehicle at the design speed. None of which is useable on the streets.

I'm sure a lot of technologies for increasing mileage have been invented and hushed. I remember Ogle's carburetor back in the 70s or whenever. It was supposed to be pretty impressive too. But I have my doubts about a lot of that when you consider how many BTUs of heat energy a gallon of gas has to start with. There's only so much work those BTUs can do, even at higher efficiency.

 

[Vanishing Nomad]

So I was thinking about electric cars. I don't know very much about physics but I do know that perpetual motion defies the laws of physics. A while back I thought why not use an alternator to recharge the batteries while in use, but you lose some energy when you convert motion to electricity, and you lose some energy when you convert electricity to motion. The total amount of energy in the car can only decrease.

Now, correct me if I'm wrong but the batteries will last a bit longer right?

What if you put a windmill contraption on the front of the car connected to another alternator to charge the batteries, and perhaps another setup for a couple solar panels. Would this be possible?

Didn't you make this exact same post, almost word for word last year some time too?

 

[Mortimer]

As others have said it really doesn't work that way, in fact you'll drain the batteries faster, due to the additional load of having to turn an alternator, which at best has an 80% efficiency at converting the mechanical rotation into electricity.

It's like pedaling a bike hooked up to an alternator connected to an electric motor to power the wheels of the bike you're pedaling . . . you're really just better off just riding the damn bike. There's a word for it -- "Rube Goldberg Machine"

The best design in this area I have seen came from Honda many years ago, they used it in one of their hybrids (can't remember which one), but it actually used braking power to help recharge the batteries. When you hit the brakes, rather than using a disc or drum brake like most cars, it actually engaged a generator to the wheels, the friction of which caused the car to slow down and also generated a little extra power for the batteries. No sense in wasting all that momentum of a 2,500lb car moving down the road.

The best and most efficient design, in my opinion, is a full-electric car with battery bank capable of maybe 60-80 miles, and a diesel/gasoline generator to provide power when the battery becomes drained.

Screw this hybrid crap. A car with two drivetrains makes no sense at all.

 

[Pangea]

I have some magnets that you place on the wheels of any vehicle, guaranteed to increase your mileage by 200%! Send $30 in a self addressed stamped envelope to find out more!!!

 

[gwrmarines]

Didn't you make this exact same post, almost word for word last year some time too?

I joined these boards two weeks ago...

 

[Beachbummer]

the problem

So I was thinking about electric cars. I don't know very much about physics but I do know that perpetual motion defies the laws of physics. A while back I thought why not use an alternator to recharge the batteries while in use, but you lose some energy when you convert motion to electricity, and you lose some energy when you convert electricity to motion. The total amount of energy in the car can only decrease.

Now, correct me if I'm wrong but the batteries will last a bit longer right?

What if you put a windmill contraption on the front of the car connected to another alternator to charge the batteries, and perhaps another setup for a couple solar panels. Would this be possible?

The problem with your plan is that you are increasing FRICTION which requires more power to overcome. That is why No perpetual motion devices exist. Friction will always be just a little ahead of the power required to move an object.

 

[Melsrogue]

I have some magnets that you place on the wheels of any vehicle, guaranteed to increase your mileage by 200%! Send $30 in a self addressed stamped envelope to find out more!!!

Psssssh! WHAT HOOEY!







I however have some magnets that you place on the wheels of any vehicle, guaranteed to increase your mileage by 800%! Send $100 in a self addressed stamped envelope to find out more!! : :thumb:

 

[MikeK]

The best design in this area I have seen came from Honda many years ago, they used it in one of their hybrids (can't remember which one), but it actually used braking power to help recharge the batteries. When you hit the brakes, rather than using a disc or drum brake like most cars, it actually engaged a generator to the wheels, the friction of which caused the car to slow down and also generated a little extra power for the batteries. No sense in wasting all that momentum of a 2,500lb car moving down the road.

Regenerative braking is a good example of capturing energy that would be wasted. I read somewhere about a team that was also working on a shock absorber system that would capture the energy wasted on damping the suspension. They said that's the most energy wasted on a vehicle and would add considerable charge to the battery bank.

Both of them combined would be about the most efficient combination of capturing useable energy without adding parasitic load. Along with maybe making the entire vehicle skin out of solar cells.

Still, it takes a helluva lot of current to propel a car. All these things would add immensely to the cost of the vehicle, while still not really extending the range enough to be worth it.

I've always felt that electric cars will never be particularly practical. If everyone had them, the entire electrical production capacity of the nation would have to increase, and so would electricity costs. They are not going to let us commute any cheaper, now that they know what we're willing to pay to drive. All that it's going to cause is everyone to pay more per KWH of power, making home utilities cost more along with everything else.