Steve Saunders Goldwing Forums banner

Status
Not open for further replies.
1 - 20 of 24 Posts

·
Premium Member
Joined
·
551 Posts
Discussion Starter #1
imported post

Just curious if how much electrical watts you use at once affects gas mileage. I would think not since the alternator is providing the electrical power and the engine is providing the combustion to power the drive train but wanted to be sure.

My mpg has dropped significantly since I've been using my heated gear but that may be due to the additives they put in gas for winter driving. Just seems like an odd coincidence.
 

·
Premium Member
Joined
·
353 Posts
imported post

Alternators have to be turned by the engine which takes gasoline. The alternator originally on the 1200s ran full bore all the time so I don't believe using juice or not using it would have any bearing on gas mileage. External alternators are a different story. The more juice you use the more difficult it is to turn the alternator thus using more engine power and gasoline.
Bobby
 

·
Premium Member
Joined
·
353 Posts
imported post

Oops! You are riding a 1500 so I don't know what type of generating device you have. If it is regulated to just produce the electrical power you need it would affect gas mileage a little. Not a lot, but some.
Bobby
 

·
Premium Member
Joined
·
2,142 Posts
imported post

Would be an interesting experiment.
 

·
Premium Member
Joined
·
2,048 Posts
imported post

The 1500 has an external alternator, and using excess electrical power would have some effect on mileage. Certainly electric riding gear (almost a dead short) would have an effect. How much of a drop did you see.
 

·
Premium Member
Joined
·
551 Posts
Discussion Starter #6
imported post

jackjohn wrote:
The 1500 has an external alternator, and using excess electrical power would have some effect on mileage. Certainly electric riding gear (almost a dead short) would have an effect. How much of a drop did you see.
About a 5 mpg drop. It went from my typical 33-34 to 28-30. Same riding conditions and style.
 

·
Premium Member
Joined
·
1,136 Posts
imported post

1 horsepower=746 watts. So, just as a very rough approximation, if your alternator is producing 350 watts, you are losing about 1/2 horsepower. This doesn't account for heat loses and efficiency, but at least gives a ballpark idea.
 

·
Premium Member
Joined
·
1,947 Posts
imported post

Gofastandfalldown wrote:
1 horsepower=746 watts. So, just as a very rough approximation, if your alternator is producing 350 watts, you are losing about 1/2 horsepower. This doesn't account for heat loses and efficiency, but at least gives a ballpark idea.
Hey Gofastandfalldown, are the Brains for $0.25 still available in your picture.?
Could use a few on stand by!:ROFL::ROFL::ROFL::ROFL:
 

·
Premium Member
Joined
·
616 Posts
imported post

As an aircraft mechanic, I specialized in confined space entry & fuel tank repair (instructed it actually). One of the things we learnt is the differences in fuels. Most fuels are not straight petrochemical stock, but a blend to suit requirements. For colder climates, particularly winter in the northern parts of the US and certainly Canada, refineries blend adding more short chain molecule petrochemicals. These lighter hydrocarbons ignite easier (lower flash point... makes starting in sub-zero temps easier), but don't put out the BTUs (have as much energy) that longer chain molecule summer blend fuel does. Sorry for the techy sounding answer, but this has a lot to do with why we get worse fuel economy in winter, Of course there's other factors, tires not being as efficient in colder temps, extended idling during warm-up, and of course in winter driving more slip sliding around (I hope you're not driving in snow on a motorcycle!). Diesel BTW, for the same volume, packs more punch than gasoline, and alcohol less. I think ethanol blended fuels are a scam (you get worse mileage for sure)- I go out-of-my-way to avoid ethanol and use gas only blends. Sometimes there can be a pretty significant difference in the quality of gas you get from the various refineries and distributors.



Regarding usingaccessories like heated vests, gloves, etc., yes, the added load is felt at the alternator - it has to work harder to accomodate this increasedload, which will have to result in some measureablenegative impact on fuel economy.
 

·
Premium Member
Joined
·
6,132 Posts
imported post

skip20 wrote:
Gofastandfalldown wrote:
1 horsepower=746 watts. So, just as a very rough approximation, if your alternator is producing 350 watts, you are losing about 1/2 horsepower. This doesn't account for heat loses and efficiency, but at least gives a ballpark idea.
Hey Gofastandfalldown, are the Brains for $0.25 still available in your picture.?
Could use a few on stand by!:ROFL::ROFL::ROFL::ROFL:
I'd take a half of one to match the half God gave me..........:praying::ROFL::ROFL::ROFL:
 

·
Premium Member
Joined
·
2,249 Posts
imported post

Well I think there are other problems. I have owned 4 GL1500 and if I got 34 I knew something was wrong. Those bikes will get 40 plus. The gas can make a difference. but I am in Illinois and our gas is always 10% ethanol. Winter blend has something else and miles with drop a couple. How about air cruise and sub filters. Have they been changed lately? And is the choke cable opening completely up when not in use?
 

·
Premium Member
Joined
·
551 Posts
Discussion Starter #12
imported post

Ghost Rider 2 wrote:
Well I think there are other problems. I have owned 4 GL1500 and if I got 34 I knew something was wrong. Those bikes will get 40 plus. The gas can make a difference. but I am in Illinois and our gas is always 10% ethanol. Winter blend has something else and miles with drop a couple. How about air cruise and sub filters. Have they been changed lately? And is the choke cable opening completely up when not in use?
All maintenance items are up to snuff Ghost Rider as I do them myself. Filters were replaced less than a year ago. My normal 33-34 mpg can be attributed to the larger jets in the 88 carbs (replaced to fix hesitation problem). I've never seen 40 mpg in the almost 20 years I've owned the bike. There's been a few threads on this issue, but many GL15 owners are getting in the low 30s for mpg.

Looks like the consensus is that the alternator working harder to generate more power for the accessories has some impact on mpg.
 

·
Piled Higher and Deeper
Joined
·
4,513 Posts
imported post

(1) As pointed out, 746 watts is 1 HP.... probably about 2% of average power, or about 1 mpg affect... (i.e., negligible)

(2) Winter gas blends are different, but again negligible differences..

(3) the real cause of decreased mileage during cold weather is primarily one factor: air density.. (a) a 50 F lower temperature will give about 10% increase in drag, and 10% decreased mpg... and (b) since the density is greater, more horsepower is available... if you use it (quicker starts, etc.) it can use even more gas too.. [another factor is increased warmup.. longer times on choke, too]
 

·
Premium Member
Joined
·
616 Posts
imported post

I respectfully disagree that the difference between summer gas & winter gas is negligible. Jim, where you live in California, the gasoline distributed in winter could be significantly different that sold in Nebraska, Minnesota or Canada. I've found a whack of info on the 'net that supports this - just Google "gasoline winter blend". Just a snippet from a site I found:

"A typical summer gasoline blend might consist of 40% FCC gas, 25% straight run gas, 15% alkylate, 18% reformate, and 2% butane. The RVP of the gasoline blend depends on how much of each component is in the blend, and what the RVP is of each component. Butane is a relatively inexpensive ingredient in gasoline, but it has the highest vapor pressure at around 52 psi.

In a gasoline blend, each component contributes a fraction to the overall RVP. In the case of butane, if there is 10% butane in the blend, it will contribute around 5.2 psi (10% of 52 psi) to the overall blend."

The difference between 2% & 10% butane total volume is very significant. The short chain molecule hydrocarbons (e.g. butane) when burnt produce less energy. Up here in Canada, on the prairies we really have long, hard winters, and winter blend gas is probably sold for a good 5 months of the year. Trust me in that we have lots of experience running the stuff, and see the difference in fuel economy.

But I digress - this thread was really about how much running electrical accessories contribute to increased fuel consumption.
 

·
Piled Higher and Deeper
Joined
·
4,513 Posts
imported post

RVP has to do with vapor pressure (i.e., volatility) and does not change the heating values that much... the difference between winter and summer blends is about 1.5% in heating value (for our motorcycle this is about 0.6 mpg loss.. like I said negligible)

Here is a clip (from page 9) of a CHEVRON paper stating that point.. with the link to the complete reference HERE (CHEVRON PAPER)

YOu will find more variation in heating value between brands and normal factors then you will by the fact that it is winter vs summer...
 

Attachments

·
Administrator
02 GL1800 w/Auto Pilot
Joined
·
59,687 Posts
imported post

Ummm, not to be a worry wart, but if a 1500 is delivering 34 mpg at normal speeds (60-80) there is nothing wrong with it.

Both my previous '94SE and my current '98SE both give a good solid all year long 34 mpg, day in and day out.

One tank MPG computations? Not worth talking about. Those I have had from 40+ down to 25+.

It all depends on the terrain, your throttle hand, winds with/against you.

I have never been able to really see any REAL difference between ethanol blends and the true blue non-alcohol fuels.

I have been tracking every single tank of fuel since I bought my 98SE just so I could argue this matter.

MPG readings all over the chart.
 

·
Premium Member
Joined
·
2,929 Posts
imported post

Alternator load is enough that we used to run an oversized pulley on the alternator on the race car I crewed on. The car would discharge at anything below about 2,000 RPM, but on a race track, you don't spend much time below 2,000 RPM. The result was decreased parasitical load from the charging system, and free horsepower, which is a good thing in a race car where there are so many rules regulating how you can and cannot get more power out of your car.
 

·
Monkey with a Football
Joined
·
19,237 Posts
imported post

Sure it does. There is no free lunch with energy. The watts you use are reflected in the fuel burn you have.
Ever had one of those headlight generators for your bike that run against the tire?
Try turning that by hand with the light off and then the light on. You will see a significant load change in the resistance to turn the generator.
However your electrical loads are fairly minor compared to the amount of energy it takes to move the vehicle so you may have trouble measuring it.
 

·
Premium Member
Joined
·
675 Posts
imported post

That's it.............going outside to disconnect my horn so I can save gas. Not saying I overuse my horn.............but..........

:ROFL:

T.
 
1 - 20 of 24 Posts
Status
Not open for further replies.
Top