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Discussion Starter #1
Factors effecting gas mileage from an article on the Escape hybrid by Bill Hammond

http://www.evworld.com/view.cfm?section ... toryid=935

Radio = .8 MPG;
Rear Defroster = .8 MPG;
Headlights = .9 MPG;
Fan on High = 1.3 MPG;
300 lbs. of extra weight = 1 MPG;
Using A/C, (opposed to having the windows) down at 60 MPH = 1.2 MPG;
Tire pressure 10 lbs. low = 1.4 MPG;
Expect a 25% drop in freezing weather compared to mild temperature.
 

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Yes, the radio thing seems out of line, but this is nevertheless a very interesting chart. My Mazda Protege "winter beater" has a pretty marginal electrical system, and you can easily tell the incremental load of:

- Rear defroster.
- Fan motor.
- Headlights.

It's even obvious when you put on the brakes, because of the brake lights.

My next Insight mod is going to be to take out the rear window defroster fuse. According to the manual, it runs in "silent mode" even if you don't push the button if the temperature is below (mumble) degrees. Surely this is a huge waste!
 

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Discussion Starter #4
Not that I could ever recomend it for safety reasons, but yes it doesn't seem to be useful most of the time and it is a major parasitic load. :wink: (Your weather may vary.)
 

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It's not clear whether the data presented in the EVWorld article about the Ford SUV hybrids is based on solid empirical evidence or not.

For over 6 months, I've been observing the incremental current of various 12V accessories in the Insight.

While I can't claim any comprehensive database, my educated guesses for the Insight would be:

Radio = 0.1 MPG; (the Insight stock radio is wimpy)
Rear Defroster = 0.3 MPG; (it doesn't cover the entire window area)
Headlights = 0.3 MPG; (more for high beams)
Fan on High = 0.2 MPG; (this is a small car)
300 lbs. of extra weight = 4 MPG; (> 15% of the vehicle weight)
Using A/C, (opposed to having the windows down at 60 MPH) = 4 MPG; (I don't have A/C, so this is based on info from other forum discussions.)
Tire pressure 10 lbs. low = 7 MPG; (for all 4 tires)
Expect a 20+% drop in freezing weather compared to mild temperature. (Possibly applicable to all types of cars. For the Insight 5 speed, the loss of lean-burn in very cold temperatures has a significant impact on FE.)
 

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Oops! :oops:

I realized after posting the last message that I'd overlooked the impact of the forced "hidden" charge, that seems to occur about 70 - 80% of the time when the headlights are on. (The MIMA modification enables that to be turned off.)
That "hidden" charge current seems to range from 6 - 10 amps, depending on outdoor temperature, battery pack SoC, and other unidentified factors.

If the hidden charge is activated by incremental current drain, the rear window defroster would also likely activate it. I haven't had a chance to check that yet.

So, considering the "hidden" charge activation effect, the headlights (and possibly the rear window defroster) could reduce fuel economy in the Insight (by my educated guestimate) by 2-3 mpg.
 

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nemystic said:
Oops! :oops:

I realized after posting the last message that I'd overlooked the impact of the forced "hidden" charge, that seems to occur about 70 - 80% of the time when the headlights are on. (The MIMA modification enables that to be turned off.)
Sorry nope :!:
(hidden charging isn't controllable with MIMA)

See:

MIMA Performance and Observations
http://www.insightcentral.net/forum/vie ... &start=210
 
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Hi All:

___The .8 mpg hit from radio use was just a typo or the guy missed the presentations actual numbers. It was .1 mpg according to the engineers at the event.


___Good Luck

___Wayne R. Gerdes
 

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Discussion Starter #10
Thanks Wayne, I gather you were there. The 0.1 figure makes a lot more sense unless you have a reeeeally big sound system. :wink: Since the Insight gets roughly double the mileage of the Explorer, I would probably double the figures for the Insight. :idea:

Nemystic, I realise that this doesn't correspond with what you have measured imperically, so perhaps there are other factors involved. Note that both rear windows have defroster elements.

Kip
 

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Insightful Trekker wrote:

"Sorry nope
(hidden charging isn't controllable with MIMA)"

Thanks for the clarification, John.
The necessary "hidden" charge is indeed independant.
I seem to have confused the "hidden" charge with the background forced charge that is often activated when the headlights are on, and that is mostly misrepresented by the stock display.

b1shmu63 wrote:

"Nemystic, I realise that this doesn't correspond with what you have measured imperically, so perhaps there are other factors involved. Note that both rear windows have defroster elements."

Now I'm curious (or possibly just confused), Kip, are you referring to "both rear windows" on the Ford Escape, or do Canadian Insights have additional utilities?

-Brian
 

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Discussion Starter #13
The large hatch window on the Insight has defrost wires and the small tinted vertical glass has them as well. This is the case on the Canadian model, but should also be true for the U.S. model.

The relative effect of the various electrical loads could be determined by measuring the current drawn by each. If one had access to a closed course on a warm windless day and used a throttle lock or cruise control to regulate the speed of a warmed up Insight, it would not take long to determine accurate figures. Perhaps next summer? :D
 

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In my experience, the A/C takes more than 4 mpg, but that may be because of the hills I drive. I am sure that all these figures are best case scenarios and another hit I take on mileage is being in a hurry and not paying attention to trying to keep the mileage at a max. I can be a pretty inconsistent variable. :shock:
Don't forget rain. I take a few mpg hit with the drag on the tires.:cry:
YMMV
robert
 
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