acensor
Posts: 365
Joined: Fri Mar 15, 2013 7:17 pm
Location: Southern Oregon

Re: Measured Wall-to-Wheels Consumption

Sun Feb 08, 2015 6:54 pm

I certainly haven't done any systematic wall-to-wheels analysis.... let alone as detailed as you folks, so I can't give you any Kilowatt-hours per mile.

What I can say is ---
A) I purchased the car in April of 2013 and when I compared my total electric power bills for the year before that date and the year AFTER that date (for the whole year or month by month) I can't detect any significant increase in my electric power bill.
And my whole electric power consumption is only about $700 per year.
Note that our power cost here in Ashland Oregon is about $0.07 per kwh (I say "about" because it's a tiered rate, with your first kwh costing less that when you get into higher consumption.
Also note we put on only about 5000 miles per year on the MiEV

B) I can pretty much tell how much I'm saving per year in out of pocket compared to if we'd kept out 2004 Toyota Corolla by estimating how much we were paying and WOULD be paying if we were driving the Toyota 5000 miles per year.

C) Rarely use the heater or AC much so may be doing better than you folks in hotter and colder climates.

D) The two really interesting numbers, IMO, to most normal non-geeks are not the miles per kilowatt-hour from the wall to wheels but --
#1 Out of pocket costs converted to "miles per gallon equivalent cost."
For that I came up with about 330 miles per gallon (with the false assumption that it cost me only 16kilowatt hours to fully charge the MiEV, and an at that time a gasoline price of nearly $4 per gallon). Knock that down by a liberal factor of 2 for reality of charging inefficeinces AND the fact that gasoline is temporarily about $2.50 per gallon, and that's still an impressive-to-non-geeks equivalent out of pocket "fuel cost" of "getting about 160 miles per gallon."
I like to use that to talk to normal folk rather than the EPA figure which is not based on the out of pocket costs at all.
#2 Fully amortized miles per gallon cost equivalent after figuring in battery replacement.
Finally, if we try to amortize in the eventual battery replacement cost (which to be honest we need to for the per mile cost) it gets much fuzzier as we all know.... in that we don't know how long the batteries will last let alone replacement costs. I made some not unreasonable assumptions about those two numbers once (but ones I would not want to place any money bets on) and find it unlikely that my real miles per gallon equivalent cost could be any lower than 80 miles per gallon even after amortizing the battery in.

Too many unknowns though. If gasoline climbs to $6+ per gallon here (as it is in many parts of the world already) my "miles per gallon equivalent cost" looks better and better (as long my electric power doesn't climb proportionally to petrol prices.) and the big unknowns is battery longevity band replacement cost.
Last edited by acensor on Thu Feb 12, 2015 8:44 am, edited 1 time in total.
Alex
{this message posted with 100% post consumer recycled electrons}
SE 2012 white with blue trim, powered by PV (~65%)
2015 Subaru Forester CVT
Two Trek street/trail bicycles optimized for mild around town use

JoeS
Site Moderator
Posts: 3897
Joined: Thu Dec 15, 2011 5:47 am
Location: Silicon Valley, California

Re: Measured Wall-to-Wheels Consumption

Sun Feb 08, 2015 11:04 pm

acensor, here is my original rant on this subject, hitting exactly the point you are making and providing a table:

http://myimiev.com/forum/viewtopic.php?p=923#p923

Updated to reflect my i-MiEV's measured wall-to-wheels consumption:

http://myimiev.com/forum/viewtopic.php?p=3710#p3710

Select two variables:

1. Cost of electricity ($/kWh)
2. Cost of gasoline ($/gallon)

From the table, find your MPG$ (a phrase FiddlerJohn nicely coined).

Perhaps continue this discussion on that thread, as it's a bit OT on this one. :roll:
EVs: 2 Wht/Blu SE Prem., '13 Tesla MS85, 3 156v CorbinSparrows (2 Li-ion), 24v EcoScoot(LiFePO4)
EV Conv: 156v '86 Ram PU, 144v '65 Saab 96
Hybrids: 48v1kW bike
ICE: '88 Isuzu Trooper. Mothballed: '67 Saab (orig.owner), '76 MBZ L206D RHD RV

misterbleepy
Posts: 224
Joined: Thu Apr 11, 2013 12:53 am
Location: Newquay, Cornwall, UK

Re: Measured Wall-to-Wheels Consumption

Mon Feb 09, 2015 5:19 am

JoeS wrote:Your numbers seem to align pretty well with my own: http://myimiev.com/forum/viewtopic.php?p=5744#p5744

My numbers should be better than yours, as my car is 4" narrower - my right foot must be heavier than yours ;-)

PS Our i-MiEV RR gauge is far better than the Leaf's GOM, IMO, and my own preference is to call it RR! :roll:

I might change it back to RR - it was originally that, but I changed it to match the jargon used by others in the UK based EV forum I also follow: https://speakev.com/
Keith B.
driving with the power of 15.667 kettles

acensor
Posts: 365
Joined: Fri Mar 15, 2013 7:17 pm
Location: Southern Oregon

Re: Measured Wall-to-Wheels Consumption

Tue Feb 10, 2015 10:36 am

"......Our i-MiEV RR gauge is far better than the Leaf's GOM, IMO, and my own preference is to call it RR........
I might change it back to RR - it was originally that, but I changed it to match the jargon used by others in the UK based EV forum I also follow...."

---------------------------
As I'm sure everyone HERE understands it should be called something like GAR... Guesstimated range remaining. :roll:
Took a slight effort to convey that to my wife.... That it SAYS miles but it may not be that. Once she got it she started calling that reading "points." As in when she wanted to take the car out loong drive next day ask me "how many points are on Ev?" :D
Stil can't QUITE get her to think in bars remaining and relate that to elevation changes and speed ahead.
But she pretty well gets the relationships between speed and range and heater use.
Alex
{this message posted with 100% post consumer recycled electrons}
SE 2012 white with blue trim, powered by PV (~65%)
2015 Subaru Forester CVT
Two Trek street/trail bicycles optimized for mild around town use

misterbleepy
Posts: 224
Joined: Thu Apr 11, 2013 12:53 am
Location: Newquay, Cornwall, UK

Re: Measured Wall-to-Wheels Consumption

Wed Feb 11, 2015 4:42 am

I changed it back to RR on the spreadsheet - less characters so more efficient/economical ;-)

This is the first time I've paid any attention to it at all, and I still don't leave it visible when driving, as I am pretty comfortable about how far I can go in the car.
I'm glad I've started logging the kWh usage reported by my home charger - I can keep a better eye on the ability of the battery pack that way.
Keith B.
driving with the power of 15.667 kettles

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