Capacity Loss on 2011-2012 LEAFs

[linkim]

all of it plays a part. as to the degree i would rate them from worst to best

1) heat
2) time
3) charge cycles

Ok, so can someone clarify for me (if we know the answer) which of the above 3 will "level off" and which are linear?


Thanks.

Another parameter that should be considered is the SOC. High temp and long time at high SOC is definitely not a set of conditions conducive to long battery life.

 

[ztanos]

Add another TX car to the list. Just the other day lost my 12th bar just at 11,000 miles. I have been following along wondering when I would go since the heat issues looks like an obvious battery problem for Nissan. luckily on a lease but was hoping to purchase the car and cont to save thousands on gas. I am a little shocked I didnt make it to the 12,000mile mark. I purchased the car with 3000miles on it from the dealer, and no they were not using the 80% charge rule when I test drove it or weeks later when I purchased the car. I did a mix of 100% charging in the winter and usually 80% summer. Still have saved over 250.00 monthly in gas. My drive distance is short about 15-25 miles a day so I dont think I have to change my driving habits yet. I will sit back and see what Nissan does about this issue for now.
http://www.flickr.com/photos/84220810@N03/7710447022/

What in the world were you driving that you saved $250/month in only 15-25 miles daily? :shock:

 

[DaveinOlyWA]

Add another TX car to the list. Just the other day lost my 12th bar just at 11,000 miles. I have been following along wondering when I would go since the heat issues looks like an obvious battery problem for Nissan. luckily on a lease but was hoping to purchase the car and cont to save thousands on gas. I am a little shocked I didnt make it to the 12,000mile mark. I purchased the car with 3000miles on it from the dealer, and no they were not using the 80% charge rule when I test drove it or weeks later when I purchased the car. I did a mix of 100% charging in the winter and usually 80% summer. Still have saved over 250.00 monthly in gas. My drive distance is short about 15-25 miles a day so I dont think I have to change my driving habits yet. I will sit back and see what Nissan does about this issue for now.
http://www.flickr.com/photos/84220810@N03/7710447022/

What in the world were you driving that you saved $250/month in only 15-25 miles daily? :shock:

i know a guy who is driving a Volt and plugs in on both ends (home and work) and he claims he is saving $300 a month over a pickup but besides being his daily commuter, it also takes care of all the errand runs from home

 

[leafwing]

Add another TX car to the list. Just the other day lost my 12th bar just at 11,000 miles. I have been following along wondering when I would go since the heat issues looks like an obvious battery problem for Nissan. luckily on a lease but was hoping to purchase the car and cont to save thousands on gas. I am a little shocked I didnt make it to the 12,000mile mark. I purchased the car with 3000miles on it from the dealer, and no they were not using the 80% charge rule when I test drove it or weeks later when I purchased the car. I did a mix of 100% charging in the winter and usually 80% summer. Still have saved over 250.00 monthly in gas. My drive distance is short about 15-25 miles a day so I dont think I have to change my driving habits yet. I will sit back and see what Nissan does about this issue for now.
http://www.flickr.com/photos/84220810@N03/7710447022/

What in the world were you driving that you saved $250/month in only 15-25 miles daily? :shock:

San Antonio is the Venice of Texas.

 

[mksE55]

Add another TX car to the list. Just the other day lost my 12th bar just at 11,000 miles. I have been following along wondering when I would go since the heat issues looks like an obvious battery problem for Nissan. luckily on a lease but was hoping to purchase the car and cont to save thousands on gas. I am a little shocked I didnt make it to the 12,000mile mark. I purchased the car with 3000miles on it from the dealer, and no they were not using the 80% charge rule when I test drove it or weeks later when I purchased the car. I did a mix of 100% charging in the winter and usually 80% summer. Still have saved over 250.00 monthly in gas. My drive distance is short about 15-25 miles a day so I dont think I have to change my driving habits yet. I will sit back and see what Nissan does about this issue for now.
http://www.flickr.com/photos/84220810@N03/7710447022/

What in the world were you driving that you saved $250/month in only 15-25 miles daily? :shock:

V8 supercharged MB and we drive it full time on weekends so both my car and my wifes SUV sits. I started tracking fuel monthly when it hit 650.00 for1 month. I really have seen some 300.00 plus drops some months but almost never less than 250.00. You dont how much you spend on gas until you start tracking it for 6 months.

 

[surfingslovak]

all of it plays a part. as to the degree i would rate them from worst to best

1) heat
2) time
3) charge cycles

Ok, so can someone clarify for me (if we know the answer) which of the above 3 will "level off" and which are linear?

I have to agree with what Dave said above. For what it's worth, I compiled a spreadsheet with the data from about 40 vehicles from the forum in late May to get a sense where this battery situation might be headed. It's a small sample, but the analysis of this data yielded exactly the same results.

Please keep in mind that I did not have access to permanent degradation figures. Gids are a simple stored capacity reading, and although they give us an idea of how much capacity the battery might have lost, it's not a 1:1 relationship. That said, I calculated the following correlation factors:

Gids/Miles:          -8.61%
Gids/Vehicle Age:   -13.58%
Gids/Ambient Temp:  -55.56%

This means that vehicle age contributes about twice as much as mileage. In another words, you would expect a one-year-old Leaf with 24 K miles to have about the same level of capacity loss as a two-year-old Leaf with 12 K miles. The higher mileage car would have twice as many full charge cycles. Mileage and charge cycles should be interchangeable in this context.

Although I excluded the Arizona Leafs from the calculation, it's pretty obvious that average ambient temperature seems to have an overwhelming effect. In the small sample I evaluated, it contributed twice as much as vehicle age and mileage combined.

We can only guess, but this could be an expression of the seasonality, which was observed earlier. Still, this is another indication that ambient temperature matters, and has a very noticeable impact on Gid counts.


Click to open

 

[JPWhite]

Gids/Miles:          -8.61%
Gids/Vehicle Age:   -13.58%
Gids/Ambient Temp:  -55.56%

Awesome analysis. Nissan NA would do well to retain you as a statistical analyst. They might learn something about their vehicles.

 

[N1ghtrider]

I have not lost the bar yet (as I can still see it), but with less than 6,000 miles on the LEAF I am only getting 5 to 6 miles out of the top bar, even with the usage gauge showing I am exceeding 5 m/kWh.

 

[DaveinOlyWA]

I dont think u can use that as accurate measurement of any degradation. I have always lostt he first bar about the same as u r seeing now and I have lost no less than 2% so far

 

[dhanson865]

all of it plays a part. as to the degree i would rate them from worst to best

1) heat
2) time
3) charge cycles

Ok, so can someone clarify for me (if we know the answer) which of the above 3 will "level off" and which are linear?


Thanks.

I'm not an engineer or any form of scientist with a degree so consider this a guess from someone who has worked in IT for 20 years (more than an armchair quarterback, less than an expert in this field).

I'm going to say

1) Heat - mostly linear, but variable by usage patterns see below

imagine there is (a, b, c, etcetera) list here of temp ranges. Each temp range ages the battery linearly compared to itself but the higher temps age the battery faster than the lower. So variations in battery temps would make this seem variable but the behavior would be roughly predictable and roughly reproducible.

2) Time - mostly linear, but variable by usage patterns see below

a) at near full charge - linear but faster than c
b) at near zero charge - linear but faster than c
c) between those two states - linear but noticeably slower than a and b

3) Charge cycles - level off

Of course all of this is self limiting as after enough charge cycles the battery becomes impractical to use even though it still works.

I wrote this totally off the cuff and it might be terribly inaccurate so if you have a better idea feel free to correct, support, detract, as you feel fit.

 

[Boomer23]

Gids/Miles:          -8.61%
Gids/Vehicle Age:   -13.58%
Gids/Ambient Temp:  -55.56%

This means that vehicle age contributes about twice as much as mileage. In another words, you would expect a one-year-old Leaf with 24 K miles to have about the same level of capacity loss as a two-year-old Leaf with 12 K miles. The higher mileage car would have twice as many full charge cycles. Mileage and charge cycles should be interchangeable in this context.

Although I excluded the Arizona Leafs from the calculation, it's pretty obvious that average ambient temperature seems to have an overwhelming effect. In the small sample I evaluated, it contributed twice as much as vehicle age and mileage combined.

Very impressive work, slovak. Looking at your raw dataset, I think that an update of the data would help to firm up your findings. I noticed that my own Gid reading has now dropped to 251 at 100% charge and if that is consistent for others, the trends that you are identifying may be more statistically significant and less affected by random error now. The temperature effect is now more impactful as well. It would be a lot of work but worth a lot to many of us who are trying to understand these phenomena better.

Thank you for your work on this.

 

[vrwl]

Very impressive work, slovak. Looking at your raw dataset, I think that an update of the data would help to firm up your findings. I noticed that my own Gid reading has now dropped to 251 at 100% charge and if that is consistent for others, the trends that you are identifying may be more statistically significant and less affected by random error now. The temperature effect is now more impactful as well. It would be a lot of work but worth a lot to many of us who are trying to understand these phenomena better.

Thank you for your work on this.

+1 I appreciate the work all of you have done this past year or so prior to my coming to this forum. I've spent a LOT of time over here in the last month trying to absorb the information and learn as much as I can about my "new" car. Without all your work and data collection, none of us would know nearly as much as we do now.

 

[EdmondLeaf]

Great job George, I really appreciate all that stat, very interesting

 

[TonyWilliams]

My update on the red 2011 LEAF, serial #2244

I called and reported my car today. I've lost 15-18% capacity (as measured in actual performance; not the insane GuessOmeter, CarWings, or other methods), however the car still has all 12 capacity bars. I expect that first 15% loss of capacity bar to disappear any day. I no longer own it.

Case # 9077839

Serial # 2244
25,344 miles
Reserved: April 20, 2010
Ordered: Sept 30, 2010
Built: March 25, 2011 in Japan
Shipped: April 25, 2011 to Long Beach, California via "Hoegh Inchon"
Arrived: at San Diego dealer May 2, 2011 (Mossy Nissan Poway)
Delivered: May 3, 2011 with 4.5 miles

The car was never exposed to exceptionally hot climates, and probably only saw temps over 90F a few times. It was never left at 100% charge for any length of time. For storage, it was left at 50%. It frequently used the entire capacity of its battery to complete 2000 miles per month. It experienced turtle mode about 20 times. It was DC fast charged 5 times or less, all but one of those times at a Nissan provided AeroVironment charger while at the "drive event" in Del Mar, California!!!!

Almost forgot that the annual battery report, completed July 2012, gave me all 5 stars!!!! It's great to know that their consumer oriented report doesn't even consider available capacity or battery degradation.

Nissan LEAF customer service:
Phone 877-664-2738
Press 1, 2, 457253
Representative: Paul Smith

Here is the result of my last drive in the car:

I drove in 75F / 23C temperature, with no significant wind (note 1), at somewhat above sea level elevation to about 580 feet / 180 meters elevation in small San Diego hills, and started and ended at my house at 580 feet elevation.

100% charge with balanced cells start
4.0 miles (6.5 km) per kWh at mostly freeway 60-65 mph (about 100 kph)
58 miles (94 km) to LBW
65 miles (105 km) to VLB (while returning to my house)

69 miles (112 km) projected range based on extensive testing with Range Chart development.

4 miles per kWh multiplied by 21 kWh of new battery available capacity = 84 miles (136 km) of new battery range.

The projected 69 miles that I drove is about 82% of expected performance with those specific driving conditions.

Note 1 - driving both directions tends to negate the impact of light wind. Wind over about 5-8 knots would need a small correction factor, even if driving both directions.

 

[dsh]

Phoenix, AZ. As on 08/04/12, I am reporting 2nd bar capacity loss on 2011 Nissan LEAF with 7,230 miles. Purchased car with only 7,063 miles and had total of 11 bars, now have total of 10.

Contacted Nissan LEAF Customer Care after noticed first bar loss and assigned case # 9074980. Spoke to Representative, who said Nissan is conducting test on battery loss, specifically as it relates to Hot Weather Climates, but testing not concluded yet. Just recontacted Nissan LEAF Customer Care today, 08/04/12 and had them add to case # that am down to 10 bars.

When go in for 24 month check up in 04/2013, will have them determine if replacing separate modules or cells will be covered under warranty.

Spoke to Nissan Leaf Service Advisor in Chandler, Arizona and he says is aware of 'battery capacity loss" issues in Arizona's hot climate, and is also waiting to see if Nissan will start recall on these vehicles to replace heat damaged modules or cells.

I am hoping they will recall vehicles being affected by premature battery capacity loss and replace modules or cell with more HEAVY DUTY design.

I guess will need to see what Nissan's testing of these vehicles in hot weather climate produces.

Anybody know cost of individual modules or cells in these LEAF battery packs?

 

[TonyWilliams]

I am hoping they will recall vehicles being affected by premature battery capacity loss and replace modules or cell with more HEAVY DUTY design.

I guess will need to see what Nissan's testing of these vehicles in hot weather climate produces.

Anybody know cost of individual modules or cells in these LEAF battery packs?

Sorry to hear of two capacity bars gone. It sounds like three or more are in your future.

You do understand that if they didn't think there would be a heat problem that they won't have a different (HEAVY DUTY or otherwise) design cell to replace your cells? Nissan engineers have been working on the next generation cell, and aren't likely to go back and redesign what was already sold with NO CAPACITY warranty. That wouldn't be very good business.

Also, Nissan is not likely to share ANY information about their testing. Anything you do hear will be processed "what they want you to "know"" info, carefully crafted and reviewed in the Nissan legal department to limit / mitigate any culpability.

I think individual cells retail for over $500.

 

[jkirkebo]

I think individual cells retail for over $500.

They do not sell individual cells, only modules with 4 cells in them. Last price I saw quoted was $662 per module.

 

[cwerdna]

I am hoping they will recall vehicles being affected by premature battery capacity loss and replace modules or cell with more HEAVY DUTY design.

I doubt there'd be a recall. Recalls are generally for safety related defects and non-compliance w/FMVSS, not problems like these.

If they were do some sort non-recall "recall", it'd probably fall under some sort of special/limited service campaign or warranty extension. Toyota's done limited service campaigns (Toyota parlance) and Nissan's done warranty extensions for various things (http://www.nissanassist.com/web/home/index.php?menu=1" onclick="window.open(this.href);return false. The first item on that site (and the only one for awhile) was the CVT warranty extension.

 

[Herm]

Phoenix, AZ. As on 08/04/12, I am reporting 2nd bar capacity loss on 2011 Nissan LEAF with 7,230 miles. Purchased car with only 7,063 miles and had total of 11 bars, now have total of 10.

Did you know the car had 11 bars when you bought it?.. Just curious how that works on resale of used Leafs.. I think yours is the first known case. Warranty or not its becoming apparent Nissan will have to do something or kiss its reputation away.

 

[JPWhite]

Warranty or not its becoming apparent Nissan will have to do something or kiss its reputation away.

+1