Capacity Loss on 2011-2012 LEAFs

[Adrian]

I know I said in my previous post I drive 80 MPH, but thinking about it, that's not really accurate.

Adrian, what is your lifetime efficiency with the Leaf?, that should describe how you drive.. but I think the important factors at this early loss is how long the battery remains at a high state of charge and at what temperature, not how you drive it.

According to Carwings, my 2011 and 2012 average energy economy is 4.5 miles/kwh. Not sure if this is the same thing as lifetime efficiency. If not, where do I find lifetime efficiency? I charge my car overnight inside my garage and always drive it the next day. So it does not stay at 100% charge more than 6 hours or so per night. I then charge it at work, which is outside, but really close to the ocean, so typically 10 degrees cooler than home. At work the car charges by noon and then stays charged until 5 or 6, sometimes later, when I drive home.

[LEAFfan]

Since the battery warranty DOES cover any capacity loss that isn't
"gradual", any intelligent person knows that a 15% or higher loss in about a year isn't gradual. So Nissan will have to fix these under their warranty. I really believe Nissan really knows this despite dealers being told to tell customers that this rate of loss is "normal."
So when it's posted that there is no battery capacity warranty, that's just not factual.

[Nubo]

Here is the same data from the Phoenix area one bar losers presented in a slightly different way that drives home the point that racking up miles more quickly leads to quicker loss of battery capacity. I have plotted Miles Driven Per Month vs. Percent capacity loss per month. Linear regression shows:

slope - 831
intercept - 168
correlation coefficient is 0.51 (moderate correlation)

Since miles driven per month means more cycling of the pack per month, it appears that both heat and cycling of the pack are factors in capacity loss

Not just number of cycles, but higher mileage rates might also correlate to deeper average discharges and a higher ratio of 100% charges.

[surfingslovak]

edit with link to battery with pink (I think airflow?)

https://docs.google.com/open?id=0B-80HT ... XRKNFdPWkE" onclick="window.open(this.href);return false;

Is there text that says that the pink is air flow?

Here is what appears to be an English-language version of the same document. The pink colored area seems to be structural support.

[GaslessInSeattle]

...
Miles vs. Capacity loss/month - correlation coefficient 0.39 (I am not posting a graph because the correlation is in the wrong direction--the fewer miles you drive, the faster you lose capacity). This doesn't make sense, and the correlation coefficient is probably too low to consider there is much correlation.

perhaps the low mileage cars sit at a higher SOC and it would make sense that since ambient temp is fairly constant across the group, the high SOC + high temp accelerates decline faster than those who charge up to go to a longer distance to work and arrive at a Low SOC for the hottest part of the day, or some other similar scenario.

[surfingslovak]

Not just number of cycles, but higher mileage rates might also correlate to deeper average discharges and a higher ratio of 100% charges.

Awesome data, great work! For what it's worth, last time I looked, the small sample I was evaluating suggested that little more than half of the capacity loss depends on the climate at the place of residence, and the rest is split roughly equally between mileage and vehicle age. The latter seemed to be more significant, but it's tough to say from a small sample. I could be wrong, but I'm under the impression that you are essentially removing the climatic effect by evaluating only cars from (roughly) the same locale.

[Stoaty]

perhaps the low mileage cars sit at a higher SOC and it would make sense that since ambient temp is fairly constant across the group, the high SOC + high temp accelerates decline faster than those who charge up to go to a longer distance to work and arrive at a Low SOC for the hottest part of the day, or some other similar scenario.

That is an excellent thought. We really need a lot more detailed info about charging patterns, average SOC, time spent at high SOC (> 80%), etc. Hard to get that data for the Wiki.

[mark1313]

I will fill that out,but if they contact me back,I will indicate Im still waiting on Mr.Perrys final decision do next month..

Received an attorney advertisement in the mail today regarding Nissan Leaf battery problems. I leased, and as long as the car meets my needs I probably won't consider this option though I have to say loosing a bar at 24k miles in Orange County annoys me. I know I charge twice a day, but there is the example of the gentleman that is at 50k miles and charges twice a day and has not lost a bar yet. I know I said in my previous post I drive 80 MPH, but thinking about it, that's not really accurate. I drive 80 MPH when traffic allows, which is probably less than half the time during my morning and afternoon commute on the HOV lane. If anyone else is interested however, the website mentioned in the letter is http://www.nissanleafproblems.com" onclick="window.open(this.href);return false; and the email was leafbattery@initiativelegal.com . The firm is in LA.

[Gonewild]

I fill out the form

[Stoaty]

Just received a PM reporting loss of 3 capacity bars from a new member, gk1. Here is his report:

"I lost my third capacity bar on my LEAF a few days ago and throught this might be interesting information to add to your list.

I lost the first bar at 3500 miles after just 3.5 month (End of June to Beginning of October - so all through summer)
I lost the second at 10500 miles after 12 month (just before the yearly battery check or just at the start of the next summer)
I lost my third capacity bar at Aug 14, 12000miles, Chandler, AZ, 12000 miles, owned: 14 months (just after we hit 118F)

I reported the first one immediately and they had the car for a cople of days and told me afterwards that this is "normal". I didn't get a case number for this, but I still have the initial email response, the battery report and the phone number of the engineer."

His VIN is listed as 05080. Leaf delivered June 27, 2011