Does this steal MPG?
 

Ok so it is very obvious that the a/c is always talked about as stealing MPG. But what about these other things? And how much? Remember to be as specific as possible because if you say "it hurts a little" that could mean to me 0.001 MPG difference or 0.5 MPG difference...
1) The Heater (Does low or high make a difference?)
2) The Defrost (I think I heard it does steal some MPG)
3) Small things in the power outlet (like a GPS or L.E.D. or something)
4) Big things in the power outlet (like a 100 or 200 Watt converter thingy)
5) The Radio (Does low or high volume make a difference?)
6) Electricity of running the wind shield wipers
And don't side track and try telling me about how dangerous it would be to go without the wind shield wipers or something because that is obvious and I wouldn't anyways. I figured these things might use up MPG from running the alternator harder or something?

Obviously they all steal mpg: the power for them has to come from somewhere, and that somewhere is the gasoline being burned in the engine.

The exception might be heater & defroster. They use waste heat that'd otherwise go to the radiator. It's the fans that use power: with proper intake/vent arrangement, without fans running they might even help mpg a tiny fraction.

Yep, power is power. :)

Maybe I am misinformed but I thought the alternator was always running and always had the same resistance, so why would it be more efficient to use less electronics when the alternator is constantly recharging the battery regardless of the consumption. If anyone could clear this up for me it would be great.

Alternator
 

This is what I thought, unless you have a huge amount of stuff going on like the huge audio systems in peoples cars where they have to get a better alternator like replacing your 94 amp alternator with a 105 or 140amp...

If the vehicle is equipped with A/C... Selecting defrost for the front windshield will turn on the A/C compressor regardless of where the temperature is set. My understanding is that the A/C will "dry" the air better therefore clearing your windshield faster.

defroster as is stated turns on the compressor in most cars.

No the alt produces only as much power as is loaded.

This is how power plants function. IF there is not enough load the turbines start to freewheel (the start turning faster) and then they reduce the amount of heat they are applying to avoid wasting coal.

If you are not running anything of your alternator(your engine is being run from batteries) the alternator is not providing any substantial resistance. Go find an electric motor of any size. turn the drive shaft without the two lead wires being connected to anything. Now turn the wires connected to something that uses electricity(thats not plugged to anything else) and turn it. Its alot harder. If the electricity flow is not being drained out of the lines the EMF resistance doesn't happen.

Think about an anenometer(wind vain). If the vain is moving slower than the wind it obviously drains the wind(if it is pumping water or something), but if you disconnect it from the pump it will spin the same speed(theoretically) as the wind and not cause any(much) resistance. Alt works the same way just consider electricity a fluid and the electrical wiring are pipes and the alt is a pump, if its already moving as fast as the pump can get it the pump doesn't require as much juice.

that said everything drains juice. Stereo systems drain however many amps they are times voltage times .013 to switch from watts to hp. That inverter roughly draws twice as much power as its rated because in converting electricity you lose alot so a 100w probably draws 125-150 and 200 250-275. fans probably run about 30 watts on loaw settings and 100w on high. Any interior LEDs use tiny amounts of power, if you mean like headlight strength LEDs they are rated in watts so it tells you quickly how much power they draw(your headlights just measure the amps times 12 volts to get watts then multiply by .013 to get hp drain.)

HypermilingNoob -

Maybe a year+ ago someone posted a list of amperage uses for different car systems. I looked for it but I can't find it.

CarloSW2

http://ecomodder.com/forum/showthrea...html#post98383 is one of them.

metrompg.com had a list of items and their associated power requirements

So in other words, The more things your running the more your alternator is having to work, the more MPG your giving up.... And basically the amount of MPG you go down are depending on the power the object consumes? I think I got it right. Now how about the heater? It uses electricity obvious but is it a large amount?

A buddy of mine had a HUGE subwoofer in his car and matching amp. Even running that thing at "listening" volume (rather than competition volume) he took a 30% hit to MPG.

No, the heat is coming from waste engine heat, that would otherwise go to the radiator. That's why, if you have a radiator block and your coolant temp starts getting too high, you can bring it down by turning on the heater.

The only extra energy it uses is the little bit of electricity needed to run the fan.

right James,

If you just flip the deal to heat and let the ambient pressure at your intake vents push the air(usually its at the windshield hood intersection) it will not consume any energy because the heat comes off the engine.

If you run the fan on low I think that table was like 30 watts. . . or .03 Kilowatts so .04 hp. . . really negligible FE improvement considering being cold is likely to slow your response time and ability to effectively hypermile.

I feel (without a lot of data to back it up) that the pulley, belt, bearings, and such of the alternator always put a noticeable load on the engine. In fact, I believe that makes up a substantial part of the ~10% MPG improvement that some people have seen by pulling their alternator belt all together. As a result, I don't think the electrical loads are going to make a huge impact on fuel economy.

The heater does take some electricity to run. Not only that, but it also cools off the coolant of the car a bit. (My dad's old car's cooling system was marginal, and on hot days he would have to run the heater to keep the car from overheating!!) A colder engine is a less efficient engine, up to a point. By running the heater, you will be cooling the engine slightly more than without running it.

Now, if your engine is fully warmed up and runing on the heater doesn't cause a noticeable drop in coolant temp, then the energy lost to the "extra" heat needed by the coolant is negligible. But running the heater during warm-up will make the warm-up phase last longer, which burns noticeably more fuel.

Not all consumption is related to work being done by the engine... :)

-soD

The alternator proper is not drawing power away from the engine unless you use it.

So 60 watts from fans on 2 settings, 200 watts for ignition. . .those aren't big numbers but the alt is having to convert from AC to DC and its only going to keep about 75-80% there. So that 60 watts of sound or air becomes 80 watts. The real savings are to elimintate he big boys like 200-300 watts of engine draw(.5 hp).

How's this for a test: Unplug all of the wires to the alternator. Check fuel economy. Then unhook the belt. Re-check economy. My belief is that you'll see a noticeable difference, which means that even when it isn't giving you any "juice", the alternator is still taking noticeable amounts of power to run.

-soD

Bit O'Data
 

Dear Mr. Noob

determining ball park parasitic loads is not too hard with instrumentation
I just pulled the serpentine and watched the scan gauge

~.1 GPH difference without any belt (from 900-3000 RPM pretty flat)
~.1 GPH difference A/C on and off (idle)
~.12 GPH difference steering wheel still vs. loaded against the stops (idle)
~.01 GPH difference head lights on and off (maybe)

Note: I could barely tell the head lights were on or off
- thus most electrical loads would be smaller and even more insignificant

during the test my unloaded consumption was ~.46 GPH
parasitic load can be 70% of my idle load and 10-20% of my cruise load

Hope this is helpful,

Let's calculate mileage impact of accessories
 

Hello, Noob,

Are you still around? Let's try answering your questions. In order to figure out the impact of various loads, we need some rules. So, I will make some up. First, we need a baseline car to look at. We are all hypermilers here, so the baseline will be an "ecomod special" that gets pretty good mileage. Here are the numbers I chose--

For the condition of interest, it takes 6 kW of power to move the car down the road. This is the actual "load," the power delivered to the tires:

Driving load..........6 kW (Energy delivered to the wheels)

Which translates to---
Gasser at 27%.....58 mpg (With 15% other losses)
EV at 70%.........227 Wh per mile = 150 mpge (at 34 kW /gal)

So, what if we just assume that all other loads have a 15% waste factored in? Then we can compare them directly to the 6 kW.

Running lights, about 250 watts?..............4% mileage penalty with lights
How much for power steering?

Okay, let's look at the list of questions--

1) The Heater (Does low or high make a difference?)
ANS: Maybe 50 watts max. for the fan.........1%
2) The Defrost (I think I heard it does steal some MPG)
ANS: If the AC runs, maybe 250 watts?........4%
3) Small things in the power outlet (like a GPS or L.E.D. or something)
ANS: Maybe 20 watts?..............................0.3%
4) Big things in the power outlet (like a 100 or 200 Watt converter thingy)
ANS: 200 watts to something.....................3.3%
5) The Radio (Does low or high volume make a difference?)
ANS: 100 watts radio + 3 watts for loud.......1.7% + .05% for loud
6) Electricity of running the wind shield wipers
ANS: Oops, sorry, I don't know. 100 watts?..1.7%

Leadfoot driving.......................................20%

So, there you are.

Ernie Rogers

To: Ernie Rogers
 

So your saying that daytime running lights use as much energy as having the a/c or defrost on? If that is true, Holy crap! well according to these calculations of his and mine my mpg should go something like this:

at 31.5 mpg originally so 378 miles per tank (assuming I run out all 12 gallons)

lead foot (@20% loss): 302.40 mpt (25.2mpg) (haha)
daytime running lights: 362.88 mpt (30.2mpg)
The Defrost (a/c): 362.88 mpt (30.2mpg)
big things (200w): 365.64 mpt (30.4mpg)
the radio (100w): 371.64 mpt (30.9mpg)
windshield wipers (100w): 371.64 mpt (30.9mpg)
The heater: 374.28 mpt (31.1mpg)
Small things: 376.92 mpt (31.4mpg)

I forget the OP topic but the engine is stealing some power for ingition and other functions.

These don't look like very major differences with them on but something Ernie accidently dropped is your alt is nowhere near 100% efficient. On a good day its 60-75%. So it takes anywhere from 30-50% more power from the engine to make those watts. The more you draw the bigger the problem. Like I said that 200w in your cigarette lighter is going to be more like 300-350 watts(.4-.5 hp).

Also adding a few of those functions together and its serious gas mileage(for quick and easy just add 1/3 more than what it cost originally to account for ALT inefficiencies).

My goal with my MPG
 

Well, if you look at my fuel graph, you can see I get a pretty constant 30.3-30.6 MPG, the EPA on my car is 25, my goal is 35 so I just wanted to see if I can start doing small things, like running my radio less to help get a little closer. In about 2 or 3 days I'm going to try acetone in my car and about 8 or 9 days after that I will make a new thread for people to see my results. I don't plan on using acetone all the time because it honestly makes me really nervous about putting it in my car but I will do it once and if the results are really good I may do it once every 5 fill ups or something along those lines.

I am just guessing on the accessories
 

To Noob:

Keeping in mind that I am mostly guessing on the accessories, that 250 watt guess was mostly for defrost. I could imagine doubling that for AC on a hot day. In a VW, the AC load is less when you have the fan on low. People see very little if any drop in mileage in a VW with AC and fan in the lowest position--it doesn't hurt the system either. Personally, I usually just drive with the AC off. That always worked when I was young and didn't have AC.

My recollection is that head lights are 90 watt bulbs. Add tail lights and all the other stuff and it is probably close to 250 watts total.

Now, about correcting for inefficiency of the alternator--I did divide by net power, after losses (the 6 kW). That means I was assuming 85% efficiency at the alternator, as with the engine and mechanicals. Remember that the alternator is always spinning and when you add a load, it is a marginal increase, which should be counted at a higher efficiency. (Much of the alternator losses are fixed, I think.)

Unchosen could easily be right that you should add a multiplier on the accessory numbers I got.

Ernie

I think acetone won't work
 

I think if your car is fairly new, the acetone won't work because a well-functioning engine achieves about 98% complete combustion. Then where will the extra energy come from?

Ernie

I don't think acetone is a good idea either. . . It vaporizes much much faster than gasoline and is much more combustible when it does. In short Acetone I can promise you is making your engine a bigger candidate for pre-ignition. Its why racers use alcohols instead of ketones to make their fuels more compression friendly. The keto groups all vaporize and burn readily, whereas alcohols take a little more effort.

The thing Acetone will add mileage for is its replacing fuel and making your engine less powerful. It honestly is just like dividing your miles by a little extra uncounted fuel when people post results(so if they add a gallon of acetone(way too much for me) they get miles divided by 9 gallons instead of normal 10, which artificially boosts results.)

You could definitely see better results from disconnecting as much load from the alt as possible. And thats very easy and very safe. If it uses Juice and you don't need it turn it off. Wanna go all out start removing the pieces. Electronics usually ambiently drain electricity. Yank speakers, radio face, wiring, air con, belt for air con, cooling fan for coolant fins, coolant fins, piping for fins, yank the compressor itself, you know they get more complicated as the list goes but not terribly more complicated.