leafme
Posts: 108
Joined: Thu Apr 22, 2010 2:27 pm
Delivery Date: 04 Jan 2011
Leaf Number: 0200
Location: San Diego, CA

Miles per kwh so far... my calcs vs. the LEAFs calcs

Tue Jan 18, 2011 10:23 pm

From 1-13-11 through 1-17-11 my calculations indicate I'm getting 3.3 mi/kwh (assuming the utility meter as my accurate reference) by dividing my odometer delta with my EVSE utility meter delta. The LEAF itself has been reporting a higher 3.6 to 3.8 mi/kwh distance per energy value (9-15% better than I'm actually getting) and Carwings is really out there with 4.7 mi/kwh. Hmmm... I'll be able to check the utility meter in the next few weeks with a power quality monitor the utility is setting at my EVSE disconnect switch and utility transformer as a test.

But for me, even at 3.3mi/kwh I'm saving a bundle over driving my 20 mpg Volvo XC90 using premium gas. The last 12 months of premium Costco gas ranged in the 3.20 to 3.40 $/g range and cost me $1,434 to travel 8,423 mi. Only a few times did I travel out of San Diego county (4 or 5 times max). This pegs my monthly Volvo costs at $1,434/12 or $120. Converting to $/mi I get 0.1702. Charging my LEAF super-off peak at 0.075 $/kwh (city of San Diego adder included) with a driving range of 3.3 mi/kwh I get 0.0227 $/mi in my LEAF (that's right, from 17c to just over 2c). This shows that my LEAF 'lectrc (credit to Randy) "fuel" costs are 0.0227/0.1702 = 13.4% of my 120 $/month Volvo costs or 16 $/month allowing me to pocket the extra 104 $/month... er... I mean... save up for my replacement battery purchase. No matter. I'm selling this car in 36 months and buying the next better model then. By then gas prices ought to be in the 85,496.279 $/g neighborhood (can't forget the "and 9/10ths" ya know).

Now, for those of you driving a Prius or other similarly fairly efficient human transportation device and getting 45 mpg with regular gas, the LEAF will still reduce your gas costs to 33% of what they were... maybe even less if you:

1. drive less freeway miles, or
2. don't use the climate control, or
3. can drive slower on the freeway... something hard to do in San Diego

This 33% (67% savings) is based on regular gas at $3.10/g, a mpg of 45, the LEAF costing 0.0227 $/mi at a super off-peak tariff rate of 0.075 $/kwh (midnight to 5am, 0000-0500 hrs, for SDG&E). This says, to break even with the LEAF "fuel" costs, with $3.10/g gas, you would need a gas powered car that can get $136 mi/g (45/0.33). That's not really a fair comparison since there are battery replacement costs at some point but it looks cool you have to admit.

99+% of my daily driving is in ECO mode, 75% of it is on the freeway during rush hour and 95+% is with the climate control ON. My daily work commute is 34 mi round trip and I'm averaging about 42 mi/day after you knock off my first day 111 mi trek to get it home from Fontana. In the last week I've upped my freeway speed to between 66-68 mph (the LEAF mileage numbers above reflect this pace). I see it as too dangerous and taking too much of my driving attention to go slower. If you try to keep it at 62 to 63 mph or less you are mostly in the right hand lane with all the freeway get-on 'ers and get-off 'ers and ALWAYS watching your rear view mirror for who is about to plow into you... Forget it. The next lane to the left (usually the # 3 lane) is much safer. For that you have to go faster or be a road hazard and go slower.

So, there you have it. My initial cost calcs for the recent 5 day period. I'll give you an update in a week or so now that I have my log up and running.

Malcolm :geek:

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evnow
Moderator
Posts: 11451
Joined: Thu Apr 22, 2010 11:41 am
Delivery Date: 25 Feb 2011
Leaf Number: 303
Location: Seattle, WA

Re: Miles per kwh so far... my calcs vs. the LEAFs calcs

Tue Jan 18, 2011 10:32 pm

leafme wrote:From 1-13-11 through 1-17-11 my calculations indicate I'm getting 3.3 mi/kwh (assuming the utility meter as my accurate reference) by dividing my odometer delta with my EVSE utility meter delta. The LEAF itself has been reporting a higher 3.6 to 3.8 mi/kwh distance per energy value (9-15% better than I'm actually getting) and Carwings is really out there with 4.7 mi/kwh. Hmmm... I'll be able to check the utility meter in the next few weeks with a power quality monitor the utility is setting at my EVSE disconnect switch and utility transformer as a test.

Yes - from what others are reporting carwings is off. You should report it to Nissan.

You would account for some charging inefficiency - so what Leaf is reporting is probably correct.
1st Leaf : 2/28/2011 to 5/6/2013
2nd Leaf : 5/4/2013 to 3/21/2017
Volt : 3/25/2017 to 5/25/2018
Model 3 : 5/10/2018 to ?

bodengroden
Posts: 47
Joined: Fri Sep 03, 2010 1:14 pm

Re: Miles per kwh so far... my calcs vs. the LEAFs calcs

Tue Jan 18, 2011 10:50 pm

Thanks for posting Malcom. We took ours out to Carlsbad on Sunday with only 85 miles on the meter. I drove 65 in the right lane mostly behind a semi. Even then the right lane in SD is a stressful place to be. I didn't venture out of the right because I know it was going to be a tight trip. But I made there and back ~70 miles with 9 miles to spare. I didn't download the carwings yet so I don't have any numbers. But I can dig them up if people want to see.

My wife usually drives the car during the week and I think she just drives it like a normal car, which in San Diego means at least 70. In fact she didn't know about the "trees" that you can grow if you drive conservatively. Oh well, if you see a white leaf zoom past you in the left lane it's probably her. She only has a 28 mile rt but routinely she comes back with ~38 miles after leaving with ~85.

darelldd
Posts: 246
Joined: Wed Apr 21, 2010 1:52 pm
Delivery Date: 28 Jan 2015
Location: Nor. Cal
Contact: Website

Re: Miles per kwh so far... my calcs vs. the LEAFs calcs

Tue Jan 18, 2011 10:56 pm

I can't speak to the carwings stuff. Not sure where it gets the info.

But as evnow mentions - seeing a different number from the car (reporting tank to wheels, I assume) and the meter (reporting plug to wheels) should be expected due to charging losses. Seems right on target to me. What number you are looking for will depend greatly on where you start accounting for it. Remember that in a gas car, everything is "tank to wheels." They don't count the losses of the delivery of the gasoline (trucking it in, pumping it into your car, the lights at the station, etc), so the nearest apples-to-apples you can get is the tank to wheels that the car is likely reporting.
Darell, the EVnut >http://evnut.com<
Email me: Domain is gmail.com. Name is darelldd@. Really. I hate PM.
2011 while SL with Chademo... new to me in 2015.

leafme
Posts: 108
Joined: Thu Apr 22, 2010 2:27 pm
Delivery Date: 04 Jan 2011
Leaf Number: 0200
Location: San Diego, CA

Re: Miles per kwh so far... my calcs vs. the LEAFs calcs

Tue Jan 18, 2011 11:02 pm

evnow wrote:
leafme wrote:From 1-13-11 through 1-17-11 my calculations indicate I'm getting 3.3 mi/kwh (assuming the utility meter as my accurate reference) by dividing my odometer delta with my EVSE utility meter delta. The LEAF itself has been reporting a higher 3.6 to 3.8 mi/kwh distance per energy value (9-15% better than I'm actually getting) and Carwings is really out there with 4.7 mi/kwh. Hmmm... I'll be able to check the utility meter in the next few weeks with a power quality monitor the utility is setting at my EVSE disconnect switch and utility transformer as a test.

Yes - from what others are reporting carwings is off. You should report it to Nissan.

You would account for some charging inefficiency - so what Leaf is reporting is probably correct.


Thanks EV. I did report it to Nissan.

My numbers reflect simple cost numbers. What do I have to pay for how many miles I get down the road? That's the only real number of value to me (and I'm guessing most people but I could be wrong). My numbers are still up for verification with a utility meter check and until then, are suspect.

Regardless of all this I continue to be a Nissan fan and applaud their entry into the market with this vehicle (actually, I love it). Just on Sunday, I'm sitting in my LEAF in my garage (reading my manual, what else) and all of a sudden I hear a shriek coming from a gal passing by with her husband and dog, pointing her finger at the car, shaking nervously saying, "That's it... that's one of them... the LEAF... how cool." I had to smile and tell them the story. It's not just a new car. We are all on the forefront of the next transportation wave.

Malcolm :geek:

leafme
Posts: 108
Joined: Thu Apr 22, 2010 2:27 pm
Delivery Date: 04 Jan 2011
Leaf Number: 0200
Location: San Diego, CA

Re: Miles per kwh so far... my calcs vs. the LEAFs calcs

Tue Jan 18, 2011 11:17 pm

bodengroden wrote:Thanks for posting Malcom. We took ours out to Carlsbad on Sunday with only 85 miles on the meter. I drove 65 in the right lane mostly behind a semi. Even then the right lane in SD is a stressful place to be. I didn't venture out of the right because I know it was going to be a tight trip. But I made there and back ~70 miles with 9 miles to spare. I didn't download the carwings yet so I don't have any numbers. But I can dig them up if people want to see.

My wife usually drives the car during the week and I think she just drives it like a normal car, which in San Diego means at least 70. In fact she didn't know about the "trees" that you can grow if you drive conservatively. Oh well, if you see a white leaf zoom past you in the left lane it's probably her. She only has a 28 mile rt but routinely she comes back with ~38 miles after leaving with ~85.


My guess is your battery life will be affected due to increased battery operating temperature. But heck, look at this this way, you are a test. Keep it up and be consistent and you can be a great data point for the industry in a year or so when you get your battery health check. Who knows, Nissan may be very conservative and we will all get better battery life results than we think. They do have a lot riding on this venture and it is for sale in Phoenix. That alone says a lot about the operating temperature environment.

One more thought, even a slight slow down will have a considerable affect on range (air resistance is a speed cubed affect which makes the energy required a speed squared affect). Stated differently, while going from 65 mph to 71.5 mph is only a 10% increase in speed, it takes 21% more energy (71.5/65 squared = 1.21) to propel you down the road. Turn it around and that means reducing your speed from 71.5 mph to 65 mph saves you 21% in battery energy to get you the same distance (albeit at a cost of time... nothing is free).

Malcolm :geek:

occ
Posts: 267
Joined: Thu Jun 24, 2010 1:14 pm
Delivery Date: 26 Jun 2015
Location: Tustin, CA

Re: Miles per kwh so far... my calcs vs. the LEAFs calcs

Tue Jan 18, 2011 11:19 pm

leafme wrote:Regardless of all this I continue to be a Nissan fan and applaud their entry into the market with this vehicle (actually, I love it). Just on Sunday, I'm sitting in my LEAF in my garage (reading my manual, what else) and all of a sudden I hear a shriek coming from a gal passing by with her husband and dog, pointing her finger at the car, shaking nervously saying, "That's it... that's one of them... the LEAF... how cool." I had to smile and tell them the story. It's not just a new car. We are all on the forefront of the next transportation wave.

Malcolm :geek:



I just love to hear that! Can't wait for my turn to help adding to the wave! Thanks Malcolm.
2011 Nissan LEAF:
Res: 4/21/10 7am
RAQ: 11/23/10 (& ordered)
Delivered: 6/17 vin 4873
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leafme
Posts: 108
Joined: Thu Apr 22, 2010 2:27 pm
Delivery Date: 04 Jan 2011
Leaf Number: 0200
Location: San Diego, CA

Re: Miles per kwh so far... my calcs vs. the LEAFs calcs

Tue Jan 18, 2011 11:21 pm

darelldd wrote:I can't speak to the carwings stuff. Not sure where it gets the info.

But as evnow mentions - seeing a different number from the car (reporting tank to wheels, I assume) and the meter (reporting plug to wheels) should be expected due to charging losses. Seems right on target to me. What number you are looking for will depend greatly on where you start accounting for it. Remember that in a gas car, everything is "tank to wheels." They don't count the losses of the delivery of the gasoline (trucking it in, pumping it into your car, the lights at the station, etc), so the nearest apples-to-apples you can get is the tank to wheels that the car is likely reporting.


Thanks Darell. Didn't expect them to be reporting tank to wheels since it's no value to me and haven't finished reading the owners manual yet. Where is that started in their literature? I must have missed it.

Malcolm :geek:

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garygid
Gold Member
Posts: 12453
Joined: Wed Apr 21, 2010 8:10 am
Delivery Date: 29 Mar 2011
Leaf Number: 000855
Location: Laguna Hills, Orange Co, CA

Re: Miles per kwh so far... my calcs vs. the LEAFs calcs

Wed Jan 19, 2011 8:18 am

The "squared" increase in energy usage for the aerodynamic drag applies only to the portion of the energy being used to overcome aero-drag.

So, if the aero-drag is about 50% of the total, then only that part goes up by 21% when the speed increases by 10%.

The part (maybe 30%) that is velocity-related (like rolling resistance) only goes up by 10%.

And the Heater and other "constant" energy uses do not increase ... their energy usage PER MILE actually decreases, since you are shortening your trip with the higher speed.

So, a 10% increase in speed typically does not require 21% increase in energy, at least until speeds at which the aero-drag becomes the dominant energy-hog!
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DeaneG
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Leaf Number: 594
Location: Cupertino, CA

Re: Miles per kwh so far... my calcs vs. the LEAFs calcs

Wed Jan 19, 2011 9:26 am

I propose we talk about AC kWh/mi to talk about wall-to-wheel numbers, and DC kWh/mi when discussing battery-to-wheel. They're different units, like quarts and liters. You have to say which one you mean unless it's clear from the context.
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