Battery Aging Model

surfingslovak said:

Would it be possible to calculate the relative aging factor for the following location: St. George, UT 84770. It would be much appreciated.

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I can do the calculation, but this map isn't for St. George, Utah (elevation 2,800 feet). It is for Cedar City, Utah (elevation 5700 feet, about 50 miles from St. George). Based on the elevation alone, I can say that Cedar City is probably going to be pretty good for the Leaf. St. George, not so much. Do you still want me to do the calculation for Cedar City?

Edit: The highs are 10-15 degrees higher in St. George than Cedar City.

Here is monthly average for Cedar City:

http://www.weather.com/weather/wxclimatology/monthly/graph/USUT0038" onclick="window.open(this.href);return false;

Here is the monthly average for St. George:

http://www.weather.com/weather/wxclimatology/monthly/graph/USUT0222" onclick="window.open(this.href);return false;

Stoaty said:

I can do the calculation, but this map isn't for St. George, Utah (elevation 2,800 feet). It is for Cedar City, Utah (elevation 5700 feet, about 50 miles from St. George).

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Thank you for doing this. It would be for a desert climate in St. George or in Ivins, UT. I would expect both to be less than ideal for the LEAF.

surfingslovak said:

Stoaty said:

I can do the calculation, but this map isn't for St. George, Utah (elevation 2,800 feet). It is for Cedar City, Utah (elevation 5700 feet, about 50 miles from St. George).

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Thank you for doing this. It would be for a desert climate in St. George or in Ivins, UT. I would expect both to be less than ideal for the LEAF.

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Looking at temperature profiles, I would say St. George is about mid-way between Dallas and Las Vegas, meaning an unscaled aging factor of about 1.41. It isn't going to be pretty, I would suggest lease only, and a short one at that.

Stoaty said:

Looking at temperature profiles, I would say St. George is about mid-way between Dallas and Las Vegas, meaning an unscaled aging factor of about 1.41. It isn't going to be pretty, I would suggest lease only, and a short one at that.

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Yes, that's what I suspected. Mark Larsen's LEAF will be facing the second summer there this year, and I suspect that he might start seeing some of the problems we have heard about from Texas and Arizona. The only saving grace is the low monthly mileage. I think adric22 still has all twelve bars, and it's because of a very short commute and low total mileage.

ronwright38 said:

DaveinOlyWA said:

ronwright38 said:

Can you tell me why i did not get to the turtle mode when i was 3 blocks to go to get home??
my leaf was sitting in the dealer showroom for 6 months and i did not know about the 12 bar's
i am sure that i did not have them as when i charged the car only showed 102 or 103 Miles and
it used to get about the 72 or so mile after driving 10 or 15 mile at 48 MPH when new then it is gitting worse . I think the battery show get a good check as it was checked and the report show 5 Stars and now i only get 55 miles after a full charge , it starts out at 88 miles and drops after 3 miles to 70 MPH
and keep's going Down going at the speed of 48 MPH. What has to happen to get the weak or bad cell or cell's replaced. If I have to wait till the bar's get to 9 to have them fixed what will the miles that i can go?? :|

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My car was sitting in the Showroom for 6 months as it was a demo for people to see before ordering the car as they did not have a supply. I live in Arizona and when it was 110 it got better mileage with the air on ,Does the heater takes more?

you need to update your profile and add a location. it is critical in these kinds of battery situations.

at least update your profile or explain to me how your car was sitting in a showroom 2 months before the first American delivery

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Ron, I sent you a personal message. Check the top left corner of this screen, just underneath the MyNissanLeaf logo (green profile of a Leaf) and you will see "Logout" on the left and just to the right of that "X New Messages." It should say at least 1 new message (from me). Click on that and you will see my PM.

surfingslovak said:

Stoaty said:

I can do the calculation, but this map isn't for St. George, Utah (elevation 2,800 feet). It is for Cedar City, Utah (elevation 5700 feet, about 50 miles from St. George).

Click to expand...

Thank you for doing this. It would be for a desert climate in St. George or in Ivins, UT. I would expect both to be less than ideal for the LEAF.

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The Temps are only a problem June, July and August. A swamp cooler in the garage could lower temps 15 to 20 degrees and the cost would be small compared to buying a new car every 2 years.

KJD said:

The Temps are only a problem June, July and August. A swamp cooler in the garage could lower temps 15 to 20 degrees and the cost would be small compared to buying a new car every 2 years.

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That sounds like a solution, provided you can leave your car in the garage for 3 months straight. For those who have to work for a living, it might be a problem.

Stoaty said:

KJD said:

The Temps are only a problem June, July and August. A swamp cooler in the garage could lower temps 15 to 20 degrees and the cost would be small compared to buying a new car every 2 years.

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That sounds like a solution, provided you can leave your car in the garage for 3 months straight. For those who have to work for a living, it might be a problem.

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Hey I have to work for a living, same as you.
My car does spend nights in the garage, same as you, same as Mark. During the day at work I make an effort to park in the shade. I just think the swamp cooler can keep the car cool at night when it is charging and that may help over the long run.

KJD said:

Stoaty said:

KJD said:

The Temps are only a problem June, July and August. A swamp cooler in the garage could lower temps 15 to 20 degrees and the cost would be small compared to buying a new car every 2 years.

Click to expand...

That sounds like a solution, provided you can leave your car in the garage for 3 months straight. For those who have to work for a living, it might be a problem.

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Hey I have to work for a living, same as you.
My car does spend nights in the garage, same as you, same as Mark. During the day at work I make an effort to park in the shade. I just think the swamp cooler can keep the car cool at night when it is charging and that may help over the long run.

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that might be doable as long as you are no higher than 70-80% SOC (purely a guess here) that will help to reduce the degradation although not sure how much since plenty of AZ'ens only charge to 80% and still had a lot. but pretty clear that ca full charge in heat is not good.

TonyWilliams said:

You are referring to the dash instrument that we call the Guess-O-Meter. Please use another method to determine how much range you may have. I recommend the Range Chart that is linked in my signature line.

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ronwright38 said:

I only use the trip meter and add the guess meter to get the 55 miles

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Don't add the GOM or use the GOM to determine range. It won't help us at ALL to determine if there is a problem. Thanks.

How many miles did you drive (physically drive) and how many fuel bars were left?

TonyWilliams said:

TonyWilliams said:

You are referring to the dash instrument that we call the Guess-O-Meter. Please use another method to determine how much range you may have. I recommend the Range Chart that is linked in my signature line.

Click to expand...

ronwright38 said:

I only use the trip meter and add the guess meter to get the 55 miles

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Don't add the GOM or use the GOM to determine range. It won't help us at ALL to determine if there is a problem. Thanks.

How many miles did you drive (physically drive) and how many fuel bars were left?

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Ron; just to add. you do realize that the GOM stops telling you anything with about 6-8 miles range left.

DaveinOlyWA said:

KJD said:

My car does spend nights in the garage, same as you, same as Mark. During the day at work I make an effort to park in the shade. I just think the swamp cooler can keep the car cool at night when it is charging and that may help over the long run.

Click to expand...

that might be doable as long as you are no higher than 70-80% SOC (purely a guess here) that will help to reduce the degradation although not sure how much since plenty of AZ'ens only charge to 80% and still had a lot. but pretty clear that ca full charge in heat is not good.

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There was an owner in Phoenix, who had an air-conditioned garage and extensive prior EV experience. This particular owner lost the first capacity bar after about 16 months of ownership. We typically get these reports after about 12 months since purchase in Phoenix. So the A/C must have helped, although it's difficult to quantify the effect exactly. This was one of the first recorded cases, and one of the earliest LEAFs. He ended up selling the car when Nissan stopped returning his phone calls, and yes, he had Mark Perry's direct line.

This model is fantastic. So thank you for building it. I can't imagine the time investment.

As an Atlantan who put 17k miles on his LEAF in Year 1, I'm absolutely thrilled with the car and its ability to save me money at the pump. The model gives me confidence that I will be able to achieve my 50 mile highway commute at 3.5mi/kWh for at least 10 years. Til then, I get plenty of overrun capacity for evening use. I could not be happier with this purchase, even though I paid sticker.

I could lament "overpaying" a year ago relative to today's deals, but only a fool would have expected prices to stay high for long.

Nissan's biggest challenge is that only a small segment of the population are interested in "thinking about" their car and its range. Until range is unconscious as it is with traditional vehicles, EVs will be a niche thing. Let's just hope Nissan bothers to continue serving the niche! I love being in this niche!

suwaneedad said:

This model is fantastic. So thank you for building it. I can't imagine the time investment.

As an Atlantan who put 17k miles on his LEAF in Year 1, I'm absolutely thrilled with the car and its ability to save me money at the pump. The model gives me confidence that I will be able to achieve my 50 mile highway commute at 3.5mi/kWh for at least 10 years.

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However, remember that the model is only a "best guess" based on available data from Nissan and climate data. I think it is generally in the ballpark, although there will certainly be outliers on either side.

PS Yes, the time invested was substantial. I think I spent about 50 hours on it, but don't recall for sure.

If 2013 LEAF does come with a electroltye localised for US conditions, then this link may be relevant.
http://www.nec.co.jp/press/en/1110/1702.html" onclick="window.open(this.href);return false;

note well
newly developed additive agent for electrolyte solutions in combination with existing manganese positive electrodes / carbon negative electrodes.


...lifespan increased by 1.5 to 3 times....


I don't know how soon the battery aging model can find this out.

further details


http://www.nec.com/en/global/techrep/journal/g12/n01/pdf/120112.pdf" onclick="window.open(this.href);return false;

I have done a bit more work on the Battery Aging Model (sample screen attached to this message):

--used a slightly different method to calculate predicted Gid Percent at 80% charge which I think is more correct; resulting values are a bit higher
--deleted some cells under fractional year prediction which were duplicates and made the sheet visually more confusing
--changed the percentages to show one decimal place instead of two (it isn't even accurate to one decimal place anyway, easier to read)
--added cells to enter actual Full Charge Gid Percent and 80% Charge Gid Percent under the fractional year area; the spreadsheet now calculates the difference between actual and predicted so it is easy to compare
--removed entries for time spent at 100% charge, as the model has no way to incorporate this information
--added a column for the incremental loss of capacity from year to year; makes it easy to see that the first year suffers by far the greatest capacity loss
--cells where data is entered all have yellow background; calculated values all have blue background
--the spreadsheet cells are currently unprotected; I will protect them (except the ones where data entry is permitted) when put on the Wiki so users don't accidentally change cells they don't want to alter)

Version 0.85 is available here (only in OpenDocument format used with OpenOffice, someone will have to update the Excel format if no problems are found):

https://dl.dropboxusercontent.com/u/48149991/Leaf%20Battery%20Degradation%20Model%20Version%20085.ods" onclick="window.open(this.href);return false;

I will add the link to the Wiki if no problems are found with this version.

Note: my Leaf is slightly outperforming the predictions for Santa Monica, CA although it spends about 40 hours a week in the hotter San Fernando Valley. It is currently 1.2% better than predicted for Full Charge and 2.1% better than predicted for 80% charge. It is 2.2% and 3.0% better than predicted for Van Nuys, CA. The correct prediction would fall somewhere between these two climates. There are only three factors that I can think of that might account for my Leaf doing unusually well for the climate:

--my very gentle acceleration not only causes less cycling of the battery (already accounted for in the model), it may be that more rapid discharge rates above one C are harder on the pack
--I keep the average SOC on my Leaf quite low (most of the time between 30-40%, while at work around 50-58%)
--(Edit): I also usually have fairly shallow cycles of the pack (about 40% DOD on most days)

Comments and questions welcome.

JPWhite has graciously provided an Excel format spreadsheet for version 0.85. I will update the Wiki this weekend with links to the new version.

JPWhite said:

I did a conversion to Excel.

https://dl.dropboxusercontent.com/u/2881567/Leaf Battery Degradation Model Version 085.xlsx

Thanks for continuing to improve the model!!

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I just want to say that I really appreciate Stoaty and J. P. White for their contributions on this subject. You guys are the "Good Guys".

derkraut said:

I just want to say that I really appreciate Stoaty and J. P. White for their contributions on this subject. You guys are the "Good Guys".

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Indeed! Great to see this update, kudos.