klindholm
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Location: Monument, Colorado

Re: Range extender !

Thu Jan 09, 2014 9:26 am

YAREI - Yet another range extender idea......

http://gizmodo.com/strap-this-wind-turb ... 1497320336

Thoughts?
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HParkEV
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Location: Toronto, Ontario

Re: Range extender !

Thu Jan 09, 2014 10:15 am

They must be kidding...
Maybe it can generate a miniscule amount of energy when the car is parked in a windy spot, but that would sure be more than offset by the extra drag it creates when you're driving around. The only way this could work is if it was removable when you drive the car, and even then it would probably not generate enough electricity when the car is parked to make it worth the hassle.
Please don't tell me this thing will generate more power than the drag it creates when you drive with it strapped to your car, because that can only happen in a different kind of universe where our laws of physics don't apply.
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fjpod
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Re: Range extender !

Thu Jan 09, 2014 1:51 pm

I could envision one built into the roof of the car...but to be used as an air scoop when the car is moving, especially at high speed. If it can truly generate 1000 watts as it claims, might it not be enough to get a decent charge while you are moving?

PV1
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Re: Range extender !

Thu Jan 09, 2014 2:56 pm

While most likely not worthwhile, what about putting these turbines in the grill opening? (The smiling mouth in the bumper?) There is airflow there that is hitting resistance (the radiator), putting drag on the car. Putting these there wouldn't change airflow over the car, just slowing the air before it hits the radiator.
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danpatgal
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Re: Range extender !

Thu Jan 09, 2014 3:13 pm

Yes, totally impractical.

But, your idea might have merit. I don't know how it could be done, but if some of the drag the car would normally incur could actually turn a generator and NOT increase the drag on the car, then you can get some of that energy back ... like regenerative braking. Or, like regenerative braking, only open an air vent with air turbine inside when you want to slow down.

But, probably totally impractical.

Don
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Re: Range extender !

Fri Jan 10, 2014 6:33 am

fjpod wrote:I could envision one built into the roof of the car...but to be used as an air scoop when the car is moving, especially at high speed. If it can truly generate 1000 watts as it claims, might it not be enough to get a decent charge while you are moving?
You wouldn't get any 'charge' because you'd be using more electricity than it generates. If it could generate more energy than it used (more electricity made than the amount of electricity it's presence cost you) then you would be the first person to actually 'invent' . . . . perpetual motion. If you pull that off, you can drive your electric car from coast to coast and never need to stop to recharge
danpatgal wrote: I don't know how it could be done, but if some of the drag the car would normally incur could actually turn a generator and NOT increase the drag on the car, then you can get some of that energy back ... like regenerative braking.
Again, you just described perpetual motion - Getting more energy back than the energy installing the device cost you. None of us know how that could be done

Even if you built a miniature 'car' with a near perfect Cd just to fit one of those 1,000 watt generators, the car's motor is always going to use more electricity moving that wind turbine down the road than the turbine can generate. There are energy losses in the cars propulsion system and also energy losses in the turbine recovering energy from the 75 mph 'wind' the cars motion creates. If you could get an energy efficiency of about 80% (recovering 800 watts while the car is using 1,000 watts) you would be doing very good . . . . but the net result is still a 20% loss, with no net energy being generated - You're still discharging the car's battery more than you are charging it

If you directly linked your electric motor output shaft to the generator's input shaft, you could eliminate lots of inefficiencies. The Cd of the car, the friction of the tires on the road, the inefficiency of the wind on the turbine's blades and you'd probably up your (in)efficiency to 90% or maybe even 95% - You could generate 900 to 950 watts using 1,000 motor watts to run the 'motor-generator'

Don
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danpatgal
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Re: Range extender !

Fri Jan 10, 2014 3:08 pm

Don wrote:
danpatgal wrote: I don't know how it could be done, but if some of the drag the car would normally incur could actually turn a generator and NOT increase the drag on the car, then you can get some of that energy back ... like regenerative braking.
Again, you just described perpetual motion Don
First of all - I am as annoyed by the lack of understanding of the Law of Conservation of Energy as anyone, so thank you for debunking the general idea of perpetual motion. I think that regenerative wind turbines deployed, or uncovered/vented, when slowing could get some energy back, just as regenerative braking does, albeit probably at much reduced efficiency, since a second generator would be required, which means if you already have regenerative braking on the main electric motor, why bother with another expensive and redundant way to do that? Verdict: stupid idea.

Now, the other stupid idea was that if there was some way to reduce drag, with say rear teardrop structure, below what was standard on the vehicle, and then add at some increased amount of drag these turbines (but remaining below the original drag), then you'd be doing better than if you did nothing. Of course, you'd do even better without the turbines at all. So, Verdict: even stupider idea.

Kuuuurija
Posts: 166
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Re: Range extender !

Fri Jan 10, 2014 7:29 pm

Don wrote:If you could get an energy efficiency of about 80% (recovering 800 watts while the car is using 1,000 watts) you would be doing very good . . . . but the net result is still a 20% loss, with no net energy being generated - You're still discharging the car's battery more than you are charging it

Please, do not use such high efficiency rates, when talking about windmills!
Betz' law limits the maximum power that can be extracted from the wind to 59.3%. In real life the efficiency is less than 50% even in most ideal conditions.
Large wind mills capture actually less than 10% of the kinetic energy of the air, that move through their blades area.

PV1
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Re: Range extender !

Fri Jan 10, 2014 9:04 pm

Pretty much any energy recovery technology we apply to a vehicle (regen included) is less efficient than leaving the energy as is and focusing on reducing usage. That's why the order is Reduce, Reuse, Recycle.

Reduce = rather obvious, reduce the amount of energy required to move the vehicle.
Reuse = coast down a hill and use the momentum to roll up the next.
Recycle = Regen, when you've either used too much energy in the first place, or need to "clear out" momentum (stop light, deer runs out in front of you, SUV pulls out in front of you, etc.). Send the energy back to where it came from (battery) to be used again.

We're facing the same dilemma as using Hydrogen as an energy carrier. Besides the better range, lithium ion beats out hydrogen in efficiency, self-discharge, and safety. A hydrogen car has the same or worse efficiency than ICE cars. About half of the energy is lost going from water to H2, and the same for the reverse. There are also transmission losses since hydrogen will leak through metal. So to gain a few more miles range, you are using more than 4 times more energy with hydrogen vs. 90% efficiency for lithium ion with almost no self discharge.
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jaraczs
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Re: Range extender !

Fri Feb 07, 2014 10:37 am

PV1 wrote:Pretty much any energy recovery technology we apply to a vehicle (regen included) is less efficient than leaving the energy as is and focusing on reducing usage. That's why the order is Reduce, Reuse, Recycle.

Thanks, PV1. I really like how the idea thread developed down to the core. As a scientist, I really like your description.

Just to build on the crazy idea of wind energy for vehicles, it would be more efficient to convert the wind energy directly into forward motion by installing sail (canvas) on the roof of the vehicle and "sail" on the road like sail boat on the ocean :) So, if you have head wind, you would have to travel in zig-zag fashion across the road! :lol:

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