Headlights saving MPG??!
Postmaster
Joined: Apr 2006
Posts: 3,524
Likes: 2
From: CA Bay Area
It is hard to imagine something invisible, but if you pay attention you might notice some indicators. On digitally controlled engine you might not notice rpm drop when you turn headlights on, but you might notice difference in engine tone.
On my conversion I do have 7500W alternator, that coupled with inverter I am using for running 1500W roof AC. When I turn the AC on idle, the engine slows down and it takes a lot to slow down Detroit 8V71.
One more tough. The 7500W alternator is run by 2 V-belts. The side fan on diesel pusher is run by 3 V-belts of the same size. And you can spin the fan by hand...
On my conversion I do have 7500W alternator, that coupled with inverter I am using for running 1500W roof AC. When I turn the AC on idle, the engine slows down and it takes a lot to slow down Detroit 8V71.
One more tough. The 7500W alternator is run by 2 V-belts. The side fan on diesel pusher is run by 3 V-belts of the same size. And you can spin the fan by hand...
Senior User
Joined: Oct 2010
Posts: 119
Likes: 0
Folks, you may be right, but I just don't get it.
Let's just agree to dis-agree as they say...
Postmaster
Joined: Apr 2006
Posts: 3,524
Likes: 2
From: CA Bay Area
Get a bigger hand generator that you crank at constant speed and have somebody behind you back switching the light on and off?
Senior User
Joined: Oct 2010
Posts: 119
Likes: 0
I tried, but my PC is not set up to view YouTube....
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Hotshot
Joined: May 2005
Posts: 13,484
Likes: 42
From: Stevens Point, WI
It is a video of me testing a weed eater motor powered alternator. Motor is running turning alternator, I put a load on the alternator and the motor dies down (loses about 3000RPM). I later did the same test but with headlights hooked up to the battery. Each headlight I turned on drug the motor down about another 1000-2000RPM until I had 2 100W bulbs and 2 55W bulbs lit, turning on 1 more 55W bulb would kill the weed eater motor because of the load the alternator put on it.
Frmr Ford Trans Engr
Joined: Aug 1999
Posts: 24,730
Likes: 2,658
From: SE Florida
Apples and oranges. The hand crank flash light has a generator, not an alternator. They are not the same. A generator DOES put out more energy when spun faster.
Senior User
Joined: Oct 2010
Posts: 119
Likes: 0
It is a video of me testing a weed eater motor powered alternator. Motor is running turning alternator, I put a load on the alternator and the motor dies down (loses about 3000RPM). I later did the same test but with headlights hooked up to the battery. Each headlight I turned on drug the motor down about another 1000-2000RPM until I had 2 100W bulbs and 2 55W bulbs lit, turning on 1 more 55W bulb would kill the weed eater motor because of the load the alternator put on it.
"electromagnetic resistance", Post #20, is not recognized by Wikipedia. I did find this;
Will there be any electromagnetic resistance to an electric generator if its not producing energy(opencircuit? - Yahoo! Answers
I now tend to be a believer...thank you all for your explanatory efforts..
Lead Driver
Joined: Sep 2007
Posts: 8,180
Likes: 669
From: Scio, OR
Pappy, you're missing a very critical aspect of the alternator.
An alternator is a set of spinning electromagnets (the field coils), inside a housing of electrical coils called the stator.
Suppose the alternator is spinning at 3000 RPM. No power is being applied to the field coils by the voltage regulator. No power is being generated by the alternator.
Now take the same alternator spinning at 3000 RPM and the voltage regulator applies voltage to the field coils. A spinning electrical field is created that cuts the stator coils of the alternator and electricity is generated.
In short, the alternator is NOT always generating electricity based on it's RPM. It's generating electricity based on the amount of power the voltage regulator applies to the field coils. If the VR says no power is needed, no power is generated and no drag occurs on the alternator. When the VR decides power is needed (battery voltage is low), it applied power to the field coils, electricity is generated and drag on the alternator is increased proportionally.
An alternator is a set of spinning electromagnets (the field coils), inside a housing of electrical coils called the stator.
Suppose the alternator is spinning at 3000 RPM. No power is being applied to the field coils by the voltage regulator. No power is being generated by the alternator.
Now take the same alternator spinning at 3000 RPM and the voltage regulator applies voltage to the field coils. A spinning electrical field is created that cuts the stator coils of the alternator and electricity is generated.
In short, the alternator is NOT always generating electricity based on it's RPM. It's generating electricity based on the amount of power the voltage regulator applies to the field coils. If the VR says no power is needed, no power is generated and no drag occurs on the alternator. When the VR decides power is needed (battery voltage is low), it applied power to the field coils, electricity is generated and drag on the alternator is increased proportionally.
Senior User
Joined: May 2004
Posts: 407
Likes: 0
From: Humble, Texas
This may be apples and oranges, but when I show up to an aircraft half awake and gulping coffee, I start the Aux Power Unit, which is just a jet engine with a big generator attached. Once it's up and running, I turn on every exterior light on the airplane so I can go outside and make sure they all work. When I turn everything on, not only do I notice a change in the tone of the APU, but I can also observe an increase in the fuel flow. I could drive my SD 600 miles on the same amount of fuel the APU uses in 20 minutes just to turn the lights on. If the lights are off with just the APU running and no bleed valves open, the same amount of fuel would last about 30 minutes.
Senior User
Joined: Dec 2009
Posts: 111
Likes: 0
From: Muncie, IN
One question I have about these new headlights; how many hours will the work before burning out compared to the factory bulbs. If I'm not mistaken the life expectancy of these new bulbs is much less than factory bulbs, therefore they will need to be replaced more often which will end up costing much more than the factory bulbs.
Mike
Mike