DaveinOlyWA
Posts: 15067
Joined: Sat Apr 24, 2010 7:43 pm
Delivery Date: 16 Nov 2019
Leaf Number: 319862
Location: Olympia, WA
Contact: Website

Re: Phoenix Range Test Sept 15, 2012 planning!

Wed Sep 19, 2012 2:29 pm

this is 1 thing I've always wondered about is how to drive the LEAF like the prius where you can have the feeling that little power is being used. I never get that feeling in the LEAF unless I an at 100% SOC or in neutral
2011 SL; 44,598 mi, 87% SOH. 2013 S; 44,840 mi, 91% SOH. 2016 S30; 29,413 mi, 99% SOH. 2018 S; 25,185 mi, SOH 92.23%. 2019 S Plus; 13,705 mi, 93.41% SOH
My Blog; http://daveinolywa.blogspot.com" onclick="window.open(this.href);return false;

EricBayArea
Posts: 672
Joined: Wed Aug 10, 2011 9:41 am
Delivery Date: 08 Oct 2011
Location: Walnut Creek, CA

Re: Phoenix Range Test Sept 15, 2012... Need 1 new PHX LEAF

Wed Sep 19, 2012 6:59 pm

shrink wrote:Image
I LOVE that they all have their tow hooks in! :lol:
Color: Cayenne Red
Plate: I PLGIN

edatoakrun
Posts: 5222
Joined: Thu Nov 11, 2010 9:33 am
Delivery Date: 15 May 2011
Leaf Number: 2184
Location: Shasta County, North California

Re: Phoenix Range Test Sept 15, 2012... Need 1 new PHX LEAF

Thu Sep 20, 2012 9:25 am

Every discussion of ascent energy recovery always seems to lead to anecdotal testimonies, leading to lack of resolution, which has led to many believe that the incorrect range of estimates on the range chart, has some validity.

As posted yesterday:
="drees"
If we're talking about how much potential energy you can recover on the way down a hill after going up and comparing efficiency to driving the same distance on flat ground - the answer is a big "it depends".

What does it depend on? Mostly, it depends on the slope of the hill and how fast you are going.

I will tell you that rolling resistance, air resistance and climate control have nothing to do with it.

Say you're cruising at 60 mph on flat ground and pulling 15 kW out of the battery to maintain speed.

Now say you encounter a slight hill which increases power requirements to 20 kW going up. Coming back down the hill of the same slope and at the same speed will only require 10 kW.

Your average power requirements will be the same 15 kW as if you kept on flat ground - IF (and it's a fairly significant IF) one assumes that the efficiency curve of the motor is flat and that any increase in resistive losses between the motor and battery are minimal (which it should be at such a modest change in power)
So for a situation like that - you do get all your potential energy back.


But if the hill is steep enough that power requirements go negative and regen is required to maintain speed - now you end up having to add in the inefficiency of regen - which is probably around 70% efficient.

So for a case where power requirements go from 15 kW to 40 kW to climb the hill at 60 mph, coming back down you need 10 kW regen to maintain 60 mph, only about 7 kW of that 10 kW will be of use.

To get actual numbers, assume that you drive for an hour. Flat ground: 15 kW * 1h = 15 kWh. Hill: 40 kW * 0.5h - 7 kW * 0.5h = 16.5 kWh. So in this case the hill will take about 10% more energy.

NOTE: Number purely back-of-the-envelope but should be in the right ballpark!
edatoakrun:

Thank you for this explenation.

Does anyone dispute: this part of "drees" comment, can we try to resolve that issue, before moving on to the next question?

What amounts of regen are actually required in descents, and so, how much additional energy is required, and how much is the driving range of the LEAF reduced, due to ascents and descents, in real-world conditions?
I can't tell, from several of the comments since yesterday, whether there are objections to ...you do get all your potential energy back... in drees statement, or if you are just objecting to his assumption:

...IF (and it's a fairly significant IF) one assumes...

If that assumption was the only part of "drees'" comment above, that anyone actually objected to. Can we all please now discuss the same question, the validity of this assumption in "drees'" statement?
no condition is permanent

User avatar
TonyWilliams
Posts: 10091
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Location: San Diego
Contact: Website

Re: Phoenix Range Test Sept 15, 2012... Need 1 new PHX LEAF

Thu Sep 20, 2012 9:42 am

edatoakrun wrote:Every discussion of ascent energy recovery always seems to lead to anecdotal testimonies, leading to lack of resolution, which has led to many believe that the incorrect range of estimates on the range chart, has some validity.
Seriously, dude, put this in the appropriate thread. I've stipulated many times, the chart data for regen is median; obviously, regen can be 0%, and some number below 100%. The chart currently says 50%-75%.

Go over to the proper thread and you post EXACTLY how you think that should be changed (that will fit on one line in a chart).

Otherwise, you're the continual blow hard with no answers. Now, off like a bunny... hop, hop, hop, over to the other thread. I'll be right behind, but no peaking. Trust me... right there.

edatoakrun
Posts: 5222
Joined: Thu Nov 11, 2010 9:33 am
Delivery Date: 15 May 2011
Leaf Number: 2184
Location: Shasta County, North California

Re: Phoenix Range Test Sept 15, 2012... Need 1 new PHX LEAF

Thu Sep 20, 2012 10:05 am

Actually, moving the discussion to the range chart thread is not a bad idea, since the lack of understanding of the fundamental difference between energy recovery by regenerative braking and ascent energy recovery, as illustrated in Tony's comments like the one below, is what seems to have led to such confusion, and the widespread acceptance of extremely inaccurate range estimates in the first place.

I think you could find several of my previous comments on the same subject on the range chart thread, which have never seemed to have penetrated into Tony's consciousness.

Maybe someone else wants to give it a try?
TonyWilliams wrote:
edatoakrun wrote:Every discussion of ascent energy recovery always seems to lead to anecdotal testimonies, leading to lack of resolution, which has led to many believe that the incorrect range of estimates on the range chart, has some validity.
Seriously, dude, put this in the appropriate thread. I've stipulated many times, the chart data for regen is median; obviously, regen can be 0%, and some number below 100%. The chart currently says 50%-75%.

Go over to the proper thread and you post EXACTLY how you think that should be changed (that will fit on one line in a chart).

Otherwise, you're the continual blow hard with no answers. Now, off like a bunny... hop, hop, hop, over to the other thread. I'll be right behind, but no peaking. Trust me... right there.
no condition is permanent

ztanos
Posts: 808
Joined: Mon Apr 30, 2012 7:31 pm
Location: Canton, Ga
Contact: AOL

Re: Phoenix Range Test Sept 15, 2012... Need 1 new PHX LEAF

Thu Sep 20, 2012 10:25 am

edatoakrun wrote:Actually, moving the discussion to the range chart thread is not a bad idea, since the lack of understanding of the fundamental difference between energy recovery by regenerative braking and ascent energy recovery, as illustrated in Tony's comments like the one below, is what seems to have led to such confusion, and the widespread acceptance of extremely inaccurate range estimates in the first place.

I think you could find several of my previous comments on the same subject on the range chart thread, which have never seemed to have penetrated into Tony's consciousness.

Maybe someone else wants to give it a try?
TonyWilliams wrote:
edatoakrun wrote:Every discussion of ascent energy recovery always seems to lead to anecdotal testimonies, leading to lack of resolution, which has led to many believe that the incorrect range of estimates on the range chart, has some validity.
Seriously, dude, put this in the appropriate thread. I've stipulated many times, the chart data for regen is median; obviously, regen can be 0%, and some number below 100%. The chart currently says 50%-75%.

Go over to the proper thread and you post EXACTLY how you think that should be changed (that will fit on one line in a chart).

Otherwise, you're the continual blow hard with no answers. Now, off like a bunny... hop, hop, hop, over to the other thread. I'll be right behind, but no peaking. Trust me... right there.
It seems to me that he has heard you, but since you haven't offered a better solution he has to stay with what he has.

GerryAZ
Gold Member
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Joined: Mon Nov 22, 2010 6:47 pm
Delivery Date: 12 Jun 2011
Location: Phoenix, AZ

Re: Phoenix Range Test Sept 15, 2012... Need 1 new PHX LEAF

Sat Sep 22, 2012 1:27 am

SierraQ wrote:
TonyWilliams wrote:2:44am, just 25 minutes before I launched my car, "Black782", on the test course. Five of us stayed up all night, and one of those pictured doesn't even own a LEAF anymore!
Who is who?
I am the guy with the long sleeve shirt who happens to have his back toward the camera in all 3 daylight pictures.

Gerry
Gerry
Silver LEAF 2011 SL rear ended (totaled) by in-attentive driver 1/4/2015 at 50,422 miles
Silver LEAF 2015 SL purchased 2/7/2015; traded 8/10/2019 at 82,436 miles
White LEAF 2019 SL Plus purchased 8/10/2019

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