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-   -   What do you think I'll get out of the HCH? (https://electricvehicleforums.com/forums/fuel-economy-emissions-22/what-do-you-think-ill-get-out-hch-905/)

lars-ss 10-22-2004 07:03 AM


Did we ever come to an agreement about using the gauge or the pump numbers? My Vette's display was consistantly around 10% higher than the pump calculations so I always used the pump numbers as the gauge was clearly in error. My 1996 Vette's display was always dead on but the 2000's is always high.
Well, my take on using the FCD versus using the tried and true "miles divided by gallons pumped" is this:

Cars for decades have been driven without computer displays for mileage. How did those folks who drove billions of miles before the advent of car computers calculate their mileage?

Miles divided by gallons pumped.

That's the calculation I use. And so far, the computer display has been HIGHER by an average of about 1.5 mpg. So if I had myself in the Real Mileage Database using my computer numbers, I would be a little higher, but I would feel like a cheater !! :P

Speaking of MPG variations:

I had my first experience of driving the HCH in the RAIN yesterday, after about 110 days of ownership (it doesn't rain much in Phoenix) and WHEW I feel sorry for high mpg drivers who live in rainy climates !!

I started my commute at 55.6, and after about 30 miles yesterday afternoon and today I am down to 53.1. I lost 2.5 MPG on this tank just after about 30 miles on rainy streets !! Whatsup with that? I realize the "rolling resistance" of the tires is lost due to drag by the water on the road, but is that the only factor? Dang !!

Hot_Georgia_2004 10-22-2004 02:44 PM


is that the only factor?
I can think of 3 things off hand:
1. Road resistance as the tires plow through the water
2. Slamming into and displacing millions of rain drops at a time (Even hold the broad side of you hand out the window and feel it)
3. Gusty winds from storm clouds

lars-ss 10-22-2004 02:53 PM

I spoke with my boss ( a very smart dude, IQ over 200) and he thought the added resistance of the effort of the tires pushing the rain away from the tire is probably a large factor, which you mentioned.

It wasn't particularly windy at all, but I was required to use my headlights. Does using the lights affect MPG in the HCH? I thought I saw a post somewhere that indicated that it was a MPG negative factor, but if it is, why would the headlight system not just be using the regular car battery instead of the Hybrid battery?

Another battery issue: I assume the car battery is not used to start the car, correct, since there is no starter and the Hybrid battery starts the car? So my question is: would a "higher cranking amps" battery installed into the vehicle help the Hybrid battery system maintain charge better/longer by taking on some of the electrical load?

I know on a regular car, a higher cranking amp battery helps the entire electrical system and on some cars it will increase the range of the keyfob lock device. So would it help an HCH at all?

Logically: If the headlights are powered by the car battery and using the headlights lowers MPG, then there MUST be a tie in between the car battery and the Hybrid battery system.

Hot_Georgia_2004 10-22-2004 06:39 PM

As I'm sure you already know, electrical devices use energy, and all energy is supplied by the ICE.
Non-IMA systems use the 12 volt battery under the hood, and this battery is also recharged by the ICE.

I've not experienced any noticable mpg reduction from using the electrical devices.

I have heard of that 12 volt battery going bad in the course of time and causing MPG problems. In that case the car senses a low voltage condition and tries hopelessly to recharge it, dragging down the MPG.

Your car also has a conventional starter in case the IMA battery is discharged below the point that can start the engine.

I've not heard of a higher amp battery extending the range of a key FOB.
I'm not sure how that is possible given the reciever consumes a miniscule ammount of current.

lakedude 10-22-2004 06:42 PM


Originally posted by lars-ss@Oct 22nd 2004 @ 4:53 PM
Logically: If the headlights are powered by the car battery and using the headlights lowers MPG, then there MUST be a tie in between the car battery and the Hybrid battery system.
Not really, anything that causes drag will lower the mileage. A traditional alternator puts more drag on an engine in proportion with the amount of power it is putting out. Headlights pull about 100 watts which is not much of a load but headlamps do decrease mpgs a small amount.

lakedude 10-22-2004 06:45 PM


Originally posted by lars-ss@Oct 22nd 2004 @ 4:53 PM
I assume the car battery is not used to start the car, correct, since there is no starter and the Hybrid battery starts the car?
Actually the car does have a regular 12v starter that is used when the big back gets low.

lars-ss 11-29-2004 08:45 AM

Here is a scenario for you, in the true vein of "What do you think I'll get out of the HCH?"

In December I will be driving my 2004 manual tranny HCH from Phoenix to central Texas. It will be myself, my 8 yr old son in a booster seat, and my 5 yr old daughter in a booster seat, with our luggage for a 10 day vacation.

Day one will be about 8 hours of driving, and the speed limits on the Interstate between Phoenix and the destination never go below 65 MPH, and mostly are 75 MPH or 70 MPH. I will be in a hurry and thus will be driving probably right at or maybe slightly (< 5 mph) above the limits.

My question is directed to other HCH owners (preferably manual tranny drivers) who have driven an 8 hour day at these speeds with a fairly loaded down car:

What kind of MPG can I expect on this Day One of the trip?

I expect to get somewhere between 40-42 MPG at those speeds with that load, but I have no point of reference - that is just a complete guess.

Does anyone have a similar trip and results they could share with me?

Thanks All !!! :D

Hot_Georgia_2004 11-29-2004 12:18 PM

Last Spring my family took a trip to Charleston, SC from Atlanta.
This is about a 6 hr trip.
My wife & I, our kids of 6, 9 and 11, and I'd guess about 150lb of luggage.

Driving up I-85 going around 65MPH (Limit 70) is extremely hilly, and the long, drawn out hills get progressively worse up to Greenville SC where I turn to the coast as the hills gradually decline.

I'm not sure of the conditions you will have but I beleive I got around 53MPG.

lars-ss 11-29-2004 01:07 PM

That's pretty darn good. I barely get 53 in City driving, using all the Hypermiler tricks. So I figure with a car loaded down and driving those speeds I can expect way less than 53.

Thanks for the input Hot_Georgia_2004.

Anyone else have a recent trip like that?

xcel 11-29-2004 02:52 PM

Hi Lars-ss:

___If you have to travel at those speeds, might I suggest you learn the various drafts? The Insight is a poor drafter as its FE when doing so is below that of non-drafts just because the big rigs are moving far to fast. I don’t know where the HCH sits in terms of this yes/no/maybe draft question but you will find out soon enough if you are actually going to be traveling at 70 + mph. The MDX and Ranger are spectacular drafters from 1/2 - 1-3/4 seconds behind at speeds up to ~ 63 mph. After that, the draft efficiency as well as their mileage drops rapidly. At least that is what I see on the X’s game gauge. In heavy 3 and 4 lane traffic, stay just below the speed of everyone else and enjoy the “Traffic Side” as this is the only draft we can all enjoy and the Insight enjoys it markedly ;) In 2 lane traffic, enjoy the “Surf” draft of the largest most ungainly 18-wheeler you can find in the other lane. Just maintain a pace maybe 3 or 4 car lengths behind and to the right in the second lane. On a single lane, it is either “Close” or “Distance” with the “Distance” being far safer. That 1-3/4 seconds is a norm in the open for me given perception and reaction time is slightly < = 1.5 seconds. Play it safe as you do have your children along for the ride. Make sure they are toddler/baby seated in the rear under all circumstances. Even if your HCH has an Airbag disable switch, they are both far safer in the rear seats then in the front. Center for your youngest but I am sure you already know these tid-bits as anyone with small children do …

___Good Luck and enjoy the trip!

___Wayne R. Gerdes
___Hunt Club Farms Landscaping Ltd.
___Waynegerdes@earthlink.net


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