Test: Alternator vs. no alternator = 10% MPG gain @ 70 km/h

[oil pan 4]

This is guy has a diesel VW.

When I put the first turbocharger on my diesel I saw at least a 2.2mpg fuel economy increase.
The turbocharger increased fuel economy, power and drivability across the board for me. I wished I had done it sooner.

[orange4boy]

you say yes but do we know that as a fact?

Yes. we know this as a fact. Scientists much smarter than you or I have done the tests and the math. No matter where you put a turbine in the airstream around a vehicle the net energy is a loss and seven less efficient than using your stock alternator Even a stationary windmill is very inefficient the only way it works is because it is harvesting energy that's generated by the sun. The wind around your car first has to be generated by the car at a very low efficiency. You can't get it back unless its going to be lost to braking anyway. Even then. it's still a net loss.

I know it seems like a flat plate would have the highest drag but your plywood reference is not correct. A turbine has drag orders of magnitude higher than the flat surface of it's blades. That's what the chart I posted shows. There isn't really a wind shadow effect of the magnitude you are hoping for. Aerodynamics is a tricky mistress.

[Xist]

Originally Posted by orange4boy

Even a stationary windmill is very inefficient the only way it works is because it is harvesting energy that's generated by the sun.

Where were you when I was taking that final May of last year?! It was something like "All renewable energy is derived from:"

I am guessing that "Jet fuel cannot melt steel" was the incorrect answer...

Hopefully, it was not actually "all..."

Most renewable energy comes either directly or indirectly from the sun. [...]

I am not sure that he explained that wind was solar-powered. Do breezes subside at night? They mention that, winds and the sun cause evaporation, and rainwater generates hydroelectric power. Precipitation and sunlight cause plants to grow, which is needed for biomass.

And the energy of the ocean's tides come from the gravitational pull of the moon and the sun upon the Earth.

Solar again! Except, the first Google result told me that the sun only pulled 3% as hard as the moon. However, the main page adds "The sun also warms the surface of the ocean more than the ocean depths, creating a temperature difference that can be used as an energy source."

Importance of Renewable Energy and Types of Renewable Energy Resources

Orange, you must have known all of that, but I am pretty sure that professor did not describe all of that, or mention that geothermal did not have anything to do with Sol.

[orange4boy]

Yeah. That's one of those test questions that makes me bonkers. You know they want you to say solar but as you pointed out the moon has a big effect on the tides. ("You can't explain that" -Bill O-Reilly, sooper genius) The real correct answer is probably extraterrestrial.

Actually, now that I think about it, the real answer is that no energy is really renewable, it's only changeable but that's on the physics tests not the eco test.

Well, I hope you passed anyway.

[ChewChewTrain]

Originally Posted by MetroMPG

(Note: this thread originally written October 2006.)

Preliminary results

Speed 70 km/h / 43.5 mph

A: alternator belt ON - 71.16 mpg (US) - avg of 3 bi-dir runs (6 one-way runs)

B: alternator belt OFF - 78.08 mpg (US) - avg of 3 bi-dir runs

A: alternator belt ON - 70.2 mpg (US) - avg of 2 bi-dir runs

Or about a 10% improvement, sans alternator

WOW! That's a huge gain. Thanks for doing the experiment.

Basically, if your trips are short enough to drive out and back on battery power ALONE, you can simply reconnect to your home charger.

In effect, you have a very crude hybrid car.

Adding more batteries will extend your range.

[MetroMPG]

Yup, it's pretty impressive.

Don't forget it may not be cost-effective though!

Frequently cycling a conventional lead acid battery will drastically reduce its life. Retrofitting other chemistries are more forgiving (but more expensive, and may require specialized chargers).

Math required, if saving money is the goal.

[cyclopathic]

Originally Posted by MetroMPG

Yup, it's pretty impressive.

Don't forget it may not be cost-effective though!

Frequently cycling a conventional lead acid battery will drastically reduce its life. Retrofitting other chemistries are more forgiving (but more expensive, and may require specialized chargers).

Math required, if saving money is the goal.

This is from delete, but how about from modifying R/R from shunt type to series? Or getting high efficiency alternator with built in series RR?

https://en.wikipedia.org/wiki/Linear_regulator

The main difference that shunt type regulators basically discharge unused electricity (turn it into heat), and series reduce output by reducing current (load)

[oil pan 4]

Alternators have been using linier regulators since the 1960s.
Alternators vary the exciter field current to produce only the needed current and voltage required by the vehicle electrical system.

[cyclopathic]

Originally Posted by oil pan 4

Alternators have been using linier regulators since the 1960s.
Alternators vary the exciter field current to produce only the needed current and voltage required by the vehicle electrical system.

which linear regulators, shunt or series?

https://en.wikipedia.org/wiki/Linear_regulator

Shunt regulators efficiency = 50-60% (constant load vs output)
Series regulators efficiency = 85-90% (reduced load per output).

I understand that you may be referring to Field regulation but I doubt all alternators have ECU to reduce field and control regulator to keep alternator at peak performance. Most of them are still simple design with constant field and shunt voltage regulator.

[MPGeo]

Originally Posted by MetroMPG

Yup, it's pretty impressive.

Thanks for sharing this info... Man this is a long thread, it's taking me two days to read... plus i got side tracked with some of the other info here...

Will have to implement, since my turbonator is a No-Go...