Inverter Drain on MPG???

[billg27]

That's all I get is 15.5 to 17.7 also. It has a lot to do with how much city driving and idling each tank. My best are when I get off, fuel and get right back on the freeway. Best milage seems to be 68-73 mph for mine. 4.8 with 3;73 rear end.

And I saw no mileage loss with my house battery, invertor and the extra weight it brings.

 

[zorry]

Would lite rock produce better mileage than heavy metal ?
Do you drive faster when a Grand Funk song comes on ?

 

[Murraycroexp]

You are pulling quite a few amps and it is possible to affect MPG as everything runs through the battery, even the E.C.M. Do you have an amp meter installed to measure the draw?
You might want to install a second battery make sure its wired parallel just like jump starting pos. red to pos. red neg. black to neg. black you will still have 12 volts but the cranking amps and reserve power will be there. Also its best to start off with both new batteries.

The second battery you can locate anywhere but its better to have both batteries fairly close together. Do not wire them in series Pos. red to Neg. black or you will burn the van to the ground as you will be pushing 24 volts through a 12 volt system. Use batteries as close to 1000 amps you will have better starting and less draw on the alternator.

When was your last tune up and PM, and what is the mileage on the van? It might be ready for a good tune up, PM and possibly a valve adjustment if over 150K.

Bob Wolf

Plugs and wires about 10K ago.
Air filter about 15K ago.
PM today and every 7K.
Tires rotated every 7K.
Air every 3-4K. Never low.

 

[Murraycroexp]

Correct.

1 horsepower = 745.699872 Watts

Watts / Volts = Amps

745.699872 Watts / 12 volts = 62.141656 amps.

150 amps / 62.141656 amps = 2.413839759918854 horsepower

A 90 amp alternator is 1.448303855951312 horsepower

The difference between an 90 amp and a 150 amp alternator is 0.965535903967542 horsepower, about 1 horsepower.

In boating they use a little metric to calculate your engine's fuel consumption at wide-open-throttle (WOT) as approximately equal to HORSEPOWER/10 = GallonsPerHour (gph).

Then, approximate the fuel consumption at a particular throttle setting as a linear percentage of the wide-open-throttle consumption in RPMs. The results give you gallons per hour at a given RMP. You can more or less translate that as an approximation to fuel economy in a car or truck.

A 300 HP diesel engine on a boat might get gallons per hour of
GPH = (0.4 x 300)/ 7.2 = 105/7.2 = 16.66666666666667 GPH

That's on a boat, though, wide open, about 4400 RPM, no gears, just running. But you can do the same with a 301 HP engine and get
GPH = (0.4 x 301)/ 7.2 = 105/7.2 = 16.72222222222222 GPH

That's a difference of 0.0555555555555522 GPH.

OK, if you get 20 MPG and drive 60 miles in an hour, that's only 3 gallons per hour, instead of the 16+ gallons per hour on a boat. So, the .055 GPH used for the extra 1 horsepower will be far, far less when you're getting 20 MPG at half the RPMs than when you are getting the 3.5 MPG at 4400 RPMs.

It's about 5.7142857 times less fuel for that 1 HP, or 0.0097222222465272 GPH, and at 20 MPG that becomes 0.00016203703744212 MPG.

That's not a tenth of a MPG (0.1) or even onethousandth of a MPG (0.001), it's one tenthousandths of a MPG. And that's what it costs you, at most (if the alternator is cranking out max amps 100% of the time), to go from a 90 amp alternator to a 150 amp alternator.

Ok, so it looks like it's NOT alternator power drain.
I am STILL intrigued by Pergoose10's ground cable project. I think it would be cool to try that.
(Heavy marine grade ground cables)

 

[Murraycroexp]

so the answer is still, his music is not causing significant loss of mpg! He's not gonna save by turning his radio off.

excellent!!! Rock on!!!

 

[Murraycroexp]

But the music fixes the noise that needs repairing. L.O.L.

That's my wife's theory!!

Uh, Sally. Sounds like the a/c compressor clutch is about to lock up!!!
"Oh, is that what that noise is?!?! I can't hear it when I turn up the radio."

::Insert twisted, disappointed face here, please.

 

[TonyD]

We never shut our inverter off. We run fridge, laptop tablets phones tv micro printer sound system etc.. no problems. 2 golf cart battery through inverter with isolator.

 

[Moot]

I run an iKicker speaker thing that makes big sound. 2 front speakers and a sub woofer in the back.

Opinions?

Speakers move air. Large speakers move a lot of air. If these speakers face forward, then all that air will push the van backwards, or at the very least blow the windshield out. Either way, a decrease in fuel mileage will result.

 

[Ragman]

Speakers move air. Large speakers move a lot of air. If these speakers face forward, then all that air will push the van backwards, or at the very least blow the windshield out. Either way, a decrease in fuel mileage will result.

 

[HighwayRover]

Here's 2 cents worth. I have a surplus military hand crank generator I set up for the kids to play with. When using the CB powered only by the hand generator, the amount of effort to maintain enough juice went up with the potential draw.
This would mean that the higher the draw, the higher the resistance or needed potential.
This means lower fuel economy.

 

[Murraycroexp]

Here's 2 cents worth. I have a surplus military hand crank generator I set up for the kids to play with. When using the CB powered only by the hand generator, the amount of effort to maintain enough juice went up with the potential draw.
This would mean that the higher the draw, the higher the resistance or needed potential.
This means lower fuel economy.

I know nothing on the subject except how to replace. I rebuilt alternators on occasion when I was in college working in a shop. But I never knew the real workings. I only know what you guys have mentioned about turning a "charged" alternator with a drill attached and how the effort required was NOT insignificant.
That said, I wonder........

Thanks!!!

 

[runrunner]

Here's 2 cents worth. I have a surplus military hand crank generator I set up for the kids to play with. When using the CB powered only by the hand generator, the amount of effort to maintain enough juice went up with the potential draw.
This would mean that the higher the draw, the higher the resistance or needed potential.
This means lower fuel economy.

The hand generator and the alternator are two different designs. The alternator can produce the required current weather it is spinning slow or fast, that is where the voltage regulator comes in. If this were not true when you idle it would not produce enough current. The resistance on the alternator pulley is always the same unlike a compressor where you have two states of operation, one free spinning and the other operating the compressor, hence the need for a clutch.

 

[Murraycroexp]

So, I could add a deep cell marine battery without an isolator and turn off my alternator for a few hours at a time. Then start it back up to charge the system up to good levels periodically?
Like NASCAR?

 

[xiggi]

Buy an isolator. You miss one load because your starter battery went dead overnight and you lost more money than your trying to save.

Sent from my Fisher Price ABC-123.

 

[OntarioVanMan]

So, I could add a deep cell marine battery without an isolator and turn off my alternator for a few hours at a time. Then start it back up to charge the system up to good levels periodically?
Like NASCAR?

This is a time NOT to cheap out....do it right the first time....Xiggi is absolutely correct...blow one load because you chose to go cheap and you've blown the ill fated plan....

 

[BobWolf]

What are the Year, make, model, and mileage?
How old is the battery, how miles since purchase or preferably hours of usage?
if you have allot of miles on the vehicle a valve adjustment may be in order.

 

[Murraycroexp]

All true, guys. Very.
2006 Express 4.8 383K.
I think it's a 140 amp, or so, alternator.

 

[Murraycroexp]

Battery about 12 months old. 785 crank from Advance.

 

[HighwayRover]

The hand generator and the alternator are two different designs. The alternator can produce the required current weather it is spinning slow or fast, that is where the voltage regulator comes in. If this were not true when you idle it would not produce enough current. The resistance on the alternator pulley is always the same unlike a compressor where you have two states of operation, one free spinning and the other operating the compressor, hence the need for a clutch.

Actually the hand crank generator is also free spinning without a clutch. The issue is not the clutch but rather the amps being drawn. The more the load (higher amps) the more resistance. The more resistance: the more effort needed to turn the gen/alt shaft. Fortunately most high tech stuff we use draws very low amps. LED lights can run forever an use very little power. CBs draw little when receiving but when transmitting they need a minimum of 2 amps for the low power sets. Some kick-arse stereos draw high amps. Voltage regulators on the other hand stop the flow to the battery when it's charged as to not blow it up.

My best advice would be to enjoy the stereo for up to the first half of your run and then learn to hum for the 2nd half. I have heard that Texas has several humming studio/schools.

 

[Murraycroexp]

I can try that. My earphones are comfortable for several hours at a time. I like theorizing.