sproqitman
Posts: 224
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Leaf Number: 0196
Location: Bellevue, WA

Re: I Beat EPA's 2.9 Miles/KWh : Report Your Monthly Mileage

Mon Apr 04, 2011 8:08 am

Here's mine. I'm not reporting CARWINGS data, since my uploads have been so intermittent.

Code: Select all

Month : March-2011
a. 650 Miles
b. 208 KWh (Wall)
c. 3.1 Miles/KWh (Wall)
d. 3.5 Miles/KWh (Leaf)
e. --- Miles/KWh (CarWings)
f. $25.00 ($0.12/KWh -- PSE + 100% renewables upcharge)
g. 3.8 Cents/Mile

DaveinOlyWA
Posts: 14149
Joined: Sat Apr 24, 2010 7:43 pm
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Leaf Number: 314199
Location: Olympia, WA
Contact: Website

Re: I Beat EPA's 2.9 Miles/KWh : Report Your Monthly Mileage

Mon Apr 04, 2011 8:21 am

How to figure cost for me is easy. I can monitor exact amount of power I use.
As far as determining costs. There are two ways and each comes out nearly identical so I took the most expensive way.
PSE uses tiered rates based on usage. I only access the lower two. What I do is divide the total kwh I use by total of bill.

The alteurnative method is to divide by only the power charged at the higher rate plu the taxes involved. This ignores the monthly service fees.
2011 SL; 44,598 miles. 2013 S; 44,840 miles.2016 S30 deceased. 29,413 miles. 2018 S40; 15,000 miles, 478 GIDs, 37.0 kwh 109.81 Ahr , SOH 94.61, Hx 120.15
My Blog; http://daveinolywa.blogspot.com" onclick="window.open(this.href);return false;

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DeaneG
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Leaf Number: 594
Location: Cupertino, CA

Re: I Beat EPA's 2.9 Miles/KWh : Report Your Monthly Mileage

Mon Apr 04, 2011 8:35 am

I think the power cost calculation should be a comparison of what your electricity bill would be if you never bought the car, vs. with the car and your current driving habits.

It's easy enough if you have a flat rate (use average cost from your bill). It's only a little harder if you have a tiered bill (use the marginal rate which probably depends on the month or season).

Things get cloudier if you switch to a TOU rate (need to compare your total TOU bill with EV consumption, vs. what your bill would have been without TOU rates and the EV).

And then if you have solar ? I added solar only because the EV would have been untenable without it, I'd have been better off buying gas for a 328i. Clearly it is reasonable to amortize some portion of the PV system cost into my EV charging cost, but not clear how much.

So, with new solar PV and a deeply funky TOU rate structure, I can't tell you how much my Leaf costs per mile within a factor of two or so. Like driving it though.
White SL w/L3, 3kWDC Solar PV

ENIAC
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Leaf Number: 224
Location: Sun Diego, CA USA

Re: I Beat EPA's 2.9 Miles/KWh : Report Your Monthly Mileage

Mon Apr 04, 2011 11:29 am

planet4ever wrote:So how are you folks coming up with cost of electricity? I can't think of any way to do that unless:
  • You never charge away from home, and
  • You don't generate your own electricity (solar or wind), and
  • You have a completely flat electric rate - no tiers and no bulk rate reduction and no time of day or day of week variation.
There's no public charging infrastructure, so very few owners can charge away from home. I don't have solar. But I do have a separate meter/billing for my EVSE, so it's simple to know exactly what my costs are.
Myths And Facts About Electric Cars

"The ice doesn't care"
-- WetEV

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DeaneG
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Re: I Beat EPA's 2.9 Miles/KWh : Report Your Monthly Mileage

Mon Apr 04, 2011 12:56 pm

ENIAC wrote:But I do have a separate meter/billing for my EVSE, so it's simple to know exactly what my costs are.
That's lucky! Was there an installation cost to be amortized for the second meter ?
White SL w/L3, 3kWDC Solar PV

DaveinOlyWA
Posts: 14149
Joined: Sat Apr 24, 2010 7:43 pm
Delivery Date: 16 Feb 2018
Leaf Number: 314199
Location: Olympia, WA
Contact: Website

Re: I Beat EPA's 2.9 Miles/KWh : Report Your Monthly Mileage

Mon Apr 04, 2011 2:48 pm

i have the opportunity to charge away from home but have chosen not to in order to get a better line on my charging efficiency. so i do know that what it costs me to drive and how far each kwh takes me so i am good.

i only really want to know why Carwings says what it says and why my car says what it says.

so its either my car also overestimates the performance like carwings and i am charging at 85+% or its pretty accurate and i am charging at 73%.

unfortunately, monitoring charge at anything other than 120 is not all that easy. so it goes.

but in the long run, it all boils down to what is coming out of my pocket and with a relatively stable ratio of wall/car, i am work with that
2011 SL; 44,598 miles. 2013 S; 44,840 miles.2016 S30 deceased. 29,413 miles. 2018 S40; 15,000 miles, 478 GIDs, 37.0 kwh 109.81 Ahr , SOH 94.61, Hx 120.15
My Blog; http://daveinolywa.blogspot.com" onclick="window.open(this.href);return false;

ENIAC
Posts: 647
Joined: Thu Jan 06, 2011 9:05 pm
Delivery Date: 13 Jan 2011
Leaf Number: 224
Location: Sun Diego, CA USA

Re: I Beat EPA's 2.9 Miles/KWh : Report Your Monthly Mileage

Mon Apr 04, 2011 2:49 pm

DeaneG wrote:
ENIAC wrote:But I do have a separate meter/billing for my EVSE, so it's simple to know exactly what my costs are.
That's lucky! Was there an installation cost to be amortized for the second meter ?
It really wasn't luck. I signed up for the EV Project as well as the SDG&E EV ToU study. So pulling the 240V 40amp circuit, second meter, and Blink EVSE were provided free of charge.
Myths And Facts About Electric Cars

"The ice doesn't care"
-- WetEV

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DeaneG
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Re: I Beat EPA's 2.9 Miles/KWh : Report Your Monthly Mileage

Tue Apr 05, 2011 8:26 am

Maybe also useful to state for item (b) how the wall AC power was measured - Blink, dedicated (second) utility meter, Kill-a-watt, etc.
White SL w/L3, 3kWDC Solar PV

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DeaneG
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Re: I Beat EPA's 2.9 Miles/KWh : Report Your Monthly Mileage

Tue Apr 05, 2011 8:30 am

For the data here so far the typical Leaf DC/Wall AC efficiency figure seems to run about 0.8, a little lower for Dave (120v charging effect?). Preheating/cooling will have a noticeable effect on this figure.
White SL w/L3, 3kWDC Solar PV

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hill
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Re: I Beat EPA's 2.9 Miles/KWh : Report Your Monthly Mileage

Tue Apr 05, 2011 8:06 pm

planet4ever wrote:So how are you folks coming up with cost of electricity? I can't think of any way to do that unless:
  • You never charge away from home, and
  • You don't generate your own electricity (solar or wind), and
  • You have a completely flat electric rate - no tiers and no bulk rate reduction and no time of day or day of week variation.
. . . . . . . . . . . . . . . . . . . . . snip
I think you're (imo) missing all the FUN of this . . . getting bogged down with cost of electricity ... whether on a tier, or TOU ... the FUN is translating the difference of what a gallon of gas would get you ... ie 34kWh ... then stating what your EV range is as an equivalent. Meah . . . maybe that's just me.
:)

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