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wsbca
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Re: What SOC% does each bar on Leaf dash represent ?

Sat Aug 06, 2011 12:42 pm

pkitchen wrote:I find all the discussion, calculations, and personal systems for estimating range fascinating and informative, but I recently discovered the best range estimate is already provided by Nissan... It's the white range circle on the Nav display!


I thought the inner circle was supposed to represent your round trip range and the outer circle was one way range...am I completely imagining that?
I was promised a jet pack!

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surfingslovak
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Re: What SOC% does each bar on Leaf dash represent ?

Sat Aug 06, 2011 4:18 pm

TonyWilliams wrote:Awesome. Why isn't 281 valued at 100% ?

As to the total usable kW, it would be handy. My trip today averaged 52mph, and 4.4miles/kWh.

If I can go 96 miles at 50mph, and 4.4kWh leaves us with 21.8 usable battery. I'm not even sure if this usable is static. For instance, if I'm really working the battery hard, is it less efficient (meaning a higher percentage of energy is lost as heat?).

The 81 mile range at 60mph is 3.7 miles/kW/h at 21.8 usable. I think I'm a couple miles short on absolute range, however.

This will all get more difficult as the batteries age.

Yes, I read up on your recent trip, excellent report. Congrats on making it back and on your meticulous planning! I punched in the data you provided, including charge times, into my calculator. It looks like the kWh estimates hold up; the predicted range was within 5 miles of your actual. I used 85% efficiency factor for charging and battery capacity numbers predicted by the model.

What exactly is the model then? It's essentially an approximate SOC point to kWh mapping. The mapping itself is speculative, but it seems to be be in alignment with other observations voiced on this forum and with the data gleaned from the few and far between comments from Nissan. I also found some very helpful information on the Tesla owners forum, and I believe that the Leaf is much closer to the Roadster in terms of charging protocols and battery care than we think or Nissan has admitted.

But back to the model. SOC 281 is not valued at 100%, because it very likely does not represent 100% pack capacity. It's the full available charge, which is less than 24kWh for the sake of battery longevity. The mapping I'm proposing assumes 320 SOC points representing 24kWh. Each point would be 0.075kWh or 75Wh. There is a silent reserve on both ends. It's likely 20 points below zero, that's what's left in the pack when the Leaf stops dead after turtle. There are another 19 points above 281 to make it full 320 SOC points. I took this metric and added pack SOC % and kWh estimates to your chart.

I've been using it during my driving to see if it holds up and so far it's been pretty good. Not 100% accurate, but good enough. I would be interested in measuring energy economy at various speeds. I drove 10 miles on a flat stretch of freeway this morning at a constant speed. I think that this could be quite useful. When you have a kWh estimate and know the distance you want to travel, you could select the most appropriate speed based on MPK measurements. You could also adjust your driving to make sure that the average MPK is within the necessary limits to get you to your destination.

DesertDenizen
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Re: What SOC% does each bar on Leaf dash represent ?

Fri Sep 09, 2011 8:44 am

I keep seeing "Dash m/kwh". How does one get the dash to display this?
[color=#0040BF]Fully charged by photo voltaic system.
Nov 9 2014 got my 2015 lease, SL. My third Leaf. Tucson AZ. 5,500 miles, 5.2 long term m/kwh. Let us see if the 'lizard' battery does better than my 2011, which lost a capacity bar at 6,771 miles.

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TonyWilliams
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Re: What SOC% does each bar on Leaf dash represent ?

Fri Sep 09, 2011 9:01 am

DesertDenizen wrote:I keep seeing "Dash m/kwh". How does one get the dash to display this?


Start your day by resetting the "miles/kWh" indicator on the dash panel right above the steering wheel. If it don't see it, find the group of four buttons to the left of the steering wheel.

In that 4 button group, the button in the upper left hand side will sequence through the various pages. When you get to the "miles/kWh" page, then use the button in the upper right hand corner of that 4 button group to reset it.

Just hold down the button (the button should have a black dot) for about 2-3 seconds. Now, you can start the day with a full charge and at the end of the day, you'll have an average miles per kWh displayed.

Use that number on this range chart to determine how far you can go. The displayed miles/kWh from the center console reads about two tenths higher. The chart is based on the dash data.

DesertDenizen
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Re: What SOC% does each bar on Leaf dash represent ?

Fri Sep 09, 2011 9:27 am

Tony, that you so much! I obviously approached reading the manuals with too much haste, and I missed that part. I need to do my homework more methodically. Thanks again.
[color=#0040BF]Fully charged by photo voltaic system.
Nov 9 2014 got my 2015 lease, SL. My third Leaf. Tucson AZ. 5,500 miles, 5.2 long term m/kwh. Let us see if the 'lizard' battery does better than my 2011, which lost a capacity bar at 6,771 miles.

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JPWhite
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Re: What SOC% does each bar on Leaf dash represent ?

Wed Sep 14, 2011 3:57 am

evnow wrote:Update : This SOC% corresponding to various bars in the Leaf dash is with the new firmware - based on this thread.

Image



I am trying to use evnow's chart to accurately calculate how many miles I can travel on each bar and therefore calculate my 80% and 100% charge estimated vehicle range.

From the chart is it reasonable to assume therefore that the amount of the 24kWh battery available to me as a driver is 21/24 - 87.5%?

I am tracking how many miles I travel per kWh of actual charge. I simply divide the total miles driven by the lifetime kWh consumed as measured by the L2 chargers I've utilized. I end up with a wall to wheels miles per kWh of 3.12. So using the above 87.5% kWh availability I end up calculating my 80% and 100% ranges as 54.55 and 65.46 miles respectively.
Here's the spreadsheet where I make my real world calculations.
http://dl.dropbox.com/u/2881567/Leaf%20Charging%20Costs%20Pub.xlsx

If these numbers hold up I should be able to translate the chart to indicate estimate range for each bar increment which should match my driving style, not some theoretical number. The calculation of just under 6 miles per bar matches what I have observed driving, so it seems at least in the ball park.

Of course other variables such as battery age, temp etc will affect the range, but something better than the guess-o-meter is needed for trip planning :-)
--
JP White
http://jpwhitenissanleaf.com
Blue SL-e, Res 4/22/10, Ord 3/29/11, Del 7/30/11
110,000 Miles.
Lost 5 Capacity bars
7/18/13 (29,206), 8/25/14 (51,728), 7/12/15 (71.108), 5/12/16 (88,362), 10/17/16 (96,532)
New Battery 12/3/16 (98,956)

mxp
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Re: What SOC% does each bar on Leaf dash represent ?

Wed Sep 14, 2011 9:58 am

Thanks for posting this chart.

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planet4ever
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Re: What SOC% does each bar on Leaf dash represent ?

Wed Sep 14, 2011 1:30 pm

JPWhite wrote:From the chart is it reasonable to assume therefore that the amount of the 24kWh battery available to me as a driver is 21/24 - 87.5%?

Forget 24 kWh. It's only use is as a Nissan advertising gimmick. As far as you are concerned, you have 21 kWh.

JPWhite wrote:I end up with a wall to wheels miles per kWh of 3.12. So using the above 87.5% kWh availability I end up calculating my 80% and 100% ranges as 54.55 and 65.46 miles respectively.

You can obviously get that same result more simply by leaving off the 87.5% and multiplying by 21. I should caution that you only have somewhere between 1 and 2 digits precision in the numbers, so you should just say 55 and 65 miles. However, you have overlooked a couple of important points:
  1. Your 3.12 is wall to wheels and the 21 is battery. There is a significant loss in getting electricity from the wall to the battery, perhaps 15% when using L2 charging.
  2. You are not going to want to run the battery down to 0% except in dire situations. You should probably allow for at least a 15% reserve.

Coincidentally, those two factors pretty much cancel each other out, so I agree with your estimated ranges, given the rather low wall-to-wheels number you are experiencing. But you should be able to increase them significantly by limiting your acceleration and braking, and your freeway speed.

Ray
End of April 2013: Traded my 2011 SL for a 2013 S with charge pkg.

LEAFfan
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Re: What SOC% does each bar on Leaf dash represent ?

Wed Sep 14, 2011 1:42 pm

TonyWilliams wrote:The displayed miles/kWh from the center console reads about two tenths higher.


Mine used to show .2 higher too until lately. Now, I've seen it the same and sometimes only .1 higher. For some reason, it never goes .2 higher anymore.
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mwalsh
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Re: What SOC% does each bar on Leaf dash represent ?

Wed Sep 14, 2011 1:57 pm

wsbca wrote:I thought the inner circle was supposed to represent your round trip range and the outer circle was one way range...am I completely imagining that?


Inner circle is D range. Outer circle is ECO range. Both one-way.
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