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Topic: Alternator ability to affect fuel usage (Read 490 times) previous topic - next topic

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  • John Haygarth
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Alternator ability to affect fuel usage
A friend here in San Carlos who has a CCoach 45ft  magna gave me this sheet to read as we where talking about charge output of alternators to batteries. Seems to really make a difference in long term fuel savings if you go to the higher output...

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Re: Alternator ability to affect fuel usage
Reply #1
That is why I always leave with my batteries fully charged. Years ago people used to argue they saved fuel by working at night, the alternate argument, did the alternator or generator in those days, take more fuel than they saved...But the truth...

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Re: Alternator ability to affect fuel usage
Reply #2
I changed to a Delco Remy 240 amp 40si ... no brushes to wear out, more efficient, less fuel, runs cooler and more available power.  It is a direct replacement. It uses a sense wire. No excite wire needed.  Digital voltage regulator. Works well...

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  • dsd
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Re: Alternator ability to affect fuel usage
Reply #3
The fact page say they were looking to increase the efficiency 25%. A larger alternator may or may not be more efficient. Nevertheless a25% increase in efficiency would safe $301.40 in 50,000 miles. During that same 50,000 miles I'm planning on...

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Re: Alternator ability to affect fuel usage
Reply #4
Guys?  746 watts equals 1 horsepower.

100 amperes at 14.4 volts equals  1,440 watts equals 2 horsepower.

Re: Alternator ability to affect fuel usage
Reply #5
Figure in efficiencies (lack of) and a 100 amp alternator takes 4-5 HP at the pulley. Your 160 amp factory alternator takes more like 8-10.  Maybe more. And that maybe 12 engine HP  An ISM11 rated at 450 HP gets about 350 HP to the road if you...

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Re: Alternator ability to affect fuel usage
Reply #6
Rodger, My friend in the trucking industry switched everything to Brushless. He also switched his Foretravel. When the time comes I also will go brushless. Most alternator failure is brushes....
Safe Travels
Dave

Re: Alternator ability to affect fuel usage
Reply #7
I went far enough in my testing to eliminate the alternators power draw.  Fully charged.  Solar running the coach while driving.

Among many other steps the results were worth the work in my opinion

Re: Alternator ability to affect fuel usage
Reply #8
Guys?  746 watts equals 1 horsepower.

100 amperes at 14.4 volts equals  1,440 watts equals 2 horsepower.

It's also unlikely that you will be pulling even 100 amps for any extended length...

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  • Twig
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Re: Alternator ability to affect fuel usage
Reply #9
Most of you people go to FOT for service and pay for work on your coach and you discuss fuel mileage? SMH.

Re: Alternator ability to affect fuel usage
Reply #10
Almost everyone wants to talk up THEIR fuel mileage.  Just a way to score points. 

On the other hand I made a deal with a customer on the idea that the prospective coach got 10mpg driven fairly hard.

"No way"  

"If it does, will you buy it?"

Yes. ...

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Re: Alternator ability to affect fuel usage
Reply #11
A friend here in San Carlos who has a CCoach 45ft  magna gave me this sheet to read as we where talking about charge output of alternators to batteries. Seems to really make a difference...


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Re: Alternator ability to affect fuel usage
Reply #12
The writer of the paper, Mike Bradfield was an Engineer at Remy, Inc. Over the course of his career he was responsible for the initial product engineering design that has led to over 3...


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Re: Alternator ability to affect fuel usage
Reply #13
What are we arguing about?  No one is claiming they are going to get significantly better mileage or save enough on fuel to pay for a new alternator. If you need a new alternator consider a newer technology, proven, more efficient brushless...

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  • John44
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Re: Alternator ability to affect fuel usage
Reply #14
Spent the week at the ladies driving school a couple of years ago, don't recall one conversation about mileage in or out of classroom.

  • John44
  • [*][*][*][*][*]
Re: Alternator ability to affect fuel usage
Reply #15
Find an old JC Whitney catalog and add up all the fuel saving devices by percentage, if you bought all of them and got over 100%
your tank would overflow.

Re: Alternator ability to affect fuel usage
Reply #16
My chassis dyno has very good resolution and shows 2 hp changes easily.  The alternator is a solid 2 plus hp draw on a car 
 I was pretty sure that my bus had a bad battery and the alternator tried to keep it at 14 volts with a bad cell ....

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Re: Alternator ability to affect fuel usage
Reply #17
What are we arguing about? 

I didn't know we were arguing Roger.  Asperger's here behind the keyboard.  My idea of fun is working, and I love percentage increase calculations.

My...

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Re: Alternator ability to affect fuel usage
Reply #18
If you combine multiple modifications you can substantially increase your coaches power AND the mpg.

Rebuild then replace the alternator.  Had a bad diode
Lowest rolling resistance tires. Correct pressure
Centrimatics
Alignment
Perfect batteries. ...

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Re: Alternator ability to affect fuel usage
Reply #19
Of course the alternator uses fuel. It uses more when the house batteries are badly discharged. It uses less when the batteries are fully charged. It also uses more with the headlights on.

So what?  I've never seen a noticeable change in fuel usage.

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Re: Alternator ability to affect fuel usage
Reply #20
The only thing that I'm trying to sort out is the alternator mods / changes as I convert to my coming solar and lithium battery installation.
    The more I read, the more confused I get cause almost every Foretravel seems a little bit different. ...

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Re: Alternator ability to affect fuel usage
Reply #21
What gauge is reading low?  And, assume it is reading one VOLT low.  Please confirm.

And, if batteries are fully charged, by shore power, generator, solar, etc alternator draw is minimal.  Said another way, if the batteries are fully charged when...

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Re: Alternator ability to affect fuel usage
Reply #22
Correct.
 It's the VDO dash volt meter that always reads about 1 volt less.  Corrected example, dash at 12. verses digital cig at 13.       Last nite with head lights and all on it ( VDO gage ) was close to the red zone but digital said 12.7...

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Re: Alternator ability to affect fuel usage
Reply #23
Does dash gauge voltage reading change when you turn on the headlights?  If so, check for good ground for gauges or just add an additional ground.

Re: Alternator ability to affect fuel usage
Reply #24
Yes,   The voltage does change when the headlights are turned on. Lowers it.   I will be adding an additional ground.
 Thanks Brett.

  And with as much chatter as I've heard on this forum about grounding issues,, I'll be embarrassed when that...

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