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More experience - more confusion?


HotLap
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Sorry folks if it appears I'm beating a dead horse here...but it seems the more I learn about and drive my new Energi, the more unsure I am about getting max mileage.  For instance, yesterday I was on a 200 mile round trip to OC and had to take the 405 freeway (Sepulveda Pass) and was unsure if using the low range was helping or hurting my mileage?  Does low gear regen charge the HBV more efficiently than regular braking does in Drive mode?  I was able to use Low mode in the stop-and- go traffic and hardly had to use the brakes at all; however, when accelerating it "feels" like Low Range takes more power to speed up...and to jump in and out of Low range repeatedly seems unwise for the longevity of the CVT?  My neighbor who owns a Volt swears that low range is the best regen but is it really and if so under what circumstances.

 

Also, when I'm on the freeway I'm in EV Later mode assuming that using EV Mode for in-town traffic is more efficient that using it on the first few miles of a longer trip?  And, when I'm in the EV Later mode and on the freeway, my regen charging is charging the Hybrid "side" of the HBV, right?  Confused as when I'm in EV Later mode the battery symbol does not switch to the simple battery view (hope that makes sense).

 

Apologize for the long post and million questions, but am really digging the FFE (HOV lane yesterday was sweeeeet!!) and want to operate as efficiently as possible....

 

On another note, my cumulative mpg over 3000 miles is 88.4mpg...I don't know the "mix" of EV to Hybrid miles that Ford used to calculate that mpg number but it is the same number that was on my window sticker, so I must be using the same %EV miles to Hybrid miles that Ford used in the calculations!

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I've personally never tried the "drive in Low" method so can't comment on that.  

 

But I have found that driving on the highway at speeds 55 or above sucks the HVB inordinately fast.  As soon as I hit the highway I go into "EV later" mode and then turn it off when things slow down.  

 

Here's how I think of the HVB battery.  By display, you basically have 105% of "the battery" labelled 100% - -5%: 100% of EV and 5% for Hybrid.  Unless you get down to 0%, it is all one battery treated the same.  Once you get to 0% then you are in Hybrid only mode using the "negative" 5% of your HVB battery.

 

With that in mind, in EV-Later mode the car "saves" a certain percentage of your EV-area of the HVB charge (so if you say to save 10% you actually still have 15: 10% - -5%).  That means it will use the HVB as much as possible while not going too far below your saved percentage and then it will use the ICE to recharge the HVB to that same level but no further.  If you get into a long-downhill run, regeneration will charge the HVB up beyond your saved amount but then as soon as you level off the car will use that surplus up before restarting the ICE to maintain your saved amount.  If you want to "grow" your saved HVB you need to turn off "EV later" at the top of the hill and then turn it back on at the bottom of the hill.  Now all the surplus regen becomes part of the Saved charge. 

 

On my homeward bound leg, I will switch back to EV-auto even on the highway such that I drop into Hybrid mode within battery-range of the house.  As long as I don't have to accelerate hard it just uses up the hybrid battery going those last couple of easy miles.

 

For me, I have approximately 8000 miles with an average commute in the 75 mile range (round trip) with about 2/3 of that highway-speed.  I've averaged 69.8MPG since the life of the car.

If I did more errands around my house I would get better numbers.  When I first got the car my MPG was 223.  Then I got a job that required lots of driving.

GK

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On another note, my cumulative mpg over 3000 miles is 88.4mpg...I don't know the "mix" of EV to Hybrid miles that Ford used to calculate that mpg number but it is the same number that was on my window sticker, so I must be using the same %EV miles to Hybrid miles that Ford used in the calculations!

 

That's not how it works.  The "88" number on the window stickers is the MPGe, which is Miles Per Gallon Equivalent.  It is the equivalent efficiency of the electric drivetrain and has absolutely nothing to do with a ratio of EV to Gasoline.

 

Here's how it's calculated:

Energy density of one gallon of gasoline = 114,000 BTU

Energy density of 1 kWH of electricity = 3,413 BTU

Therefore, 33.4 kWH has the equivalent energy as one gallon of gasoline (114,000/3,413)

88 MPGe means the vehicle would travel 88 miles on 33.4 kWH of electricity.

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Gentlemen, thank you for the feedback above.   Learning more about this car all the time and Greg 70mpg is still a great number!  I have a neighbor who has an EV, (I shall not name the brand as I don't want to start brand bashing here), and likes to boast that he gets 600+ mpg, but the way he gets it is somewhat misleading in that he ONLY drives in electric, for his daily commute.  For all other (long and short distance) trips they take their gas guzzling SUV, which I point out to him sort of defeats the purpose?  I'm trying to convince him to install a 220v in his garage so he can use the EV for around town, etc. To each his own, but IMO his approach seems to partially defeat the purpose of an EV.  Any of us can make our mileage soar by limiting the use of our EVs to electric driving only...I applaud those of you using your EVs for your longer trips as well as I suspect you are still being more efficient than switching between cars just to maintain an unrealistic mpg number...

 

Kybuck, thanks for sorting out the MPGe number and how it's determined, appreciate that!

 

In the end, the way I see it is that I traded in a truck that averaged between 12 - 14 mpg for an EV that's (3000 miles to date) averaging 88mpg...doing the same driving I was doing with the truck.  That's a HUGE increase as I'm getting approx. 6.8 times the mileage I was getting with my truck...

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HotLap, does your neighbor use the SUV so that he can maintain his good MPG (at least in his mind)? Yes, 600mpg is misleading, but I have used terms like that, since my cost to recharge my car is only $.045 per kW, so its very negligible. I typically don't use fuel over the course of the week doing all my errands and commuting on electric. But on the weekend when I have farther to go, I still use my car as intended and burn fuel as needed.

Kybuck thanks for the clarification, what I had read related everything back to cost of fuel and cost of electricity (i.e. for 1 gallon of fuel at $4, you buy $4 in electricity @ $.125kW and you can go 88 miles). Your explanation makes far more sense.

 

HotLap, driving in low range just forces the car to use max regen every time you let off the throttle. So in a way, yes you are recovering the max the car can ever time you let off the throttle, but... you can achieve the same level of regen by pushing on the brake. It comes down to driving style. I prefer not to have that on throttle/brake feel that driving in low creates. The other problem with driving in low, is if you have a full charge, and your in low, the engine will start to create engine braking since there is no place for the electricity to go when you have a full battery (only a problem right after charging the car).

 

My preference is to drive normal, and use my regen braking as much as possible.

 

Someone that knows more can clarify, but I don't think shifting into low range vs Drive actually changes anything in the transmission, just changes what the mapping of how the CVT is operating, in other words, shifting from drive to low to drive to low, etc doesn't create extra wear. But I agree, I don't like the idea, so I don't do that. Murphy/Jeff do you guys know how it works?

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I have no inside knowledge but my impression is it increases the regeneration which causes the car to slow down more quickly.  The bad part of that is that the brake lights are not turned on so the car behind you may not immediately realize that you are slowing. 

 

This is the way a Tesla works except if the deceleration is above a set point, determined by speed, the brake lights are turned on.  There is no regeneration attached to the brake pedal in a Tesla.

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