Capacity Loss on 2011-2012 LEAFs

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mkjayakumar said:
Or Nissan didn't expect such a level of degradation on hot areas in a short amount of time..
That would be my guess. They wanted to hide early capacity loss for several years, but didn't count on the "Phoenix Phenomenon". :(
 
Considering the wide divergence between the loss of the first tick and the subsequent ticks, that is not at all surprising... One hopes that it is because loss of capacity is expected to be nonlinear and to slow down over time rather that Nissan wanting to hide the loss of the first bar as long as possible...

I'd love to see some reports on how the Volt is doing under these same conditions with its thermally managed pack... It could prove very telling, one way OR the other.

opossum said:
Word today is that there's a car here right now at one of the Phoenix dealers that lost a second capacity bar. It's not our (drea / opossum, #0500) car, but I predict we will also join the 2-bar club very soon... unfortunately!
 
Nissan really needs to adopt a better PR approach to this to avoid brand damage. I think we could all relax a lot more if they simply said, "we are watching developments closely and will consider warranty work as warranted. Thank you for participating in the first mass adoption of electric vehicles in hot climates, your real world data is critical to future EV development". Also, they should clearly shift to Lease only of Leaf's in the effected markets immediately. A one to two bar loss a year is going to lead to what any one in their reasonable mind would call a pack failure well in advance of the warranty running out regardless of what the legal definition of "gradual" is. Arguing about what the definition of "is" is, only works for popular presidents. Nissan certainly has assured that they have the legal upper hand contractually, but the court of popular opinion is so much less forgiving that they will want to stay ahead of the customer satisfaction curve if they want to stay in the EV market.

How they handle this will substantially influence my next EV purchase. So far, with range fluctuations in cold whether and now premature loss in hot climates, I'm having a hard time not concluding that TMS is key in all but the most moderate climates. designing for moderate climates is probably just not worthwhile, because it causes a car to become geographically limited. IMHO, TMS in every EV will likely be the market trend at least until if/when a battery chemistry is discovered that can truly handle high high heat.

opossum said:
...
Word today is that there's a car here right now at one of the Phoenix dealers that lost a second capacity bar. It's not our (drea / opossum, #0500) car, but I predict we will also join the 2-bar club very soon... unfortunately!
 
I wonder if Nissan will pull some kWhrs out of the hat sometime down the road. The battery is 24 kWhr, we are only using 21. If they provide access to some of that buffer it will be like swimming in that pool in "Cocoon," instant capacity rejuvenation!
 
TomT said:
I'd love to see some reports on how the Volt is doing under these same conditions with its thermally managed pack... It could prove very telling, one way OR the other.
Considering that they are tweaking the chemistry for more energy and increasing the usable percentage for the 2013 Volt, I assume that they are very happy with the way the batteries are holding up.

It sure seems that for certain use cases some amount of thermal management is a good idea:

1. Multiple QCs in a day - seems that air cooling is good idea to cool the pack down.
2. Hot ambient temperatures - a combination of reducing maximum SOC and some sort of cooling might go a long way towards improving calendar life.

Biggest issue with cooling while the car is sitting is how do you do it without draining the pack?

I believe that the Tesla Roadster will cool the pack when unplugged until the pack reaches a certain SOC, at which point it will let temperatures get higher. Not sure how the Volt handles this. I know the Tesla will draw grid power to mange pack temperatures when plugged in - what does the Volt do?

Edit: This chart over on gm-volt.com seems to cover it: Volt thermal management system temperature band?. In a nutshell - if plugged in or car is on and battery is over 72*F and SOC is over 75%, cooling system will run periodically to cool off the pack. If not plugged in, battery temp must be over 86*F and SOC over 75% to cool. Remember that "75%" is lower since 75% is referring to usable capacity - actual SOC at "75%" is probably around 60% SOC or so. Since the Volt uses a similar chemistry as the LEAF, it might make sense to mimic the Volt's behavior.
 
drees said:
Edit: This chart over on gm-volt.com seems to cover it: Volt thermal management system temperature band?. In a nutshell - if plugged in or car is on and battery is over 72*F and SOC is over 75%, cooling system will run periodically to cool off the pack. If not plugged in, battery temp must be over 86*F and SOC over 75% to cool. Remember that "75%" is lower since 75% is referring to usable capacity - actual SOC at "75%" is probably around 60% SOC or so. Since the Volt uses a similar chemistry as the LEAF, it might make sense to mimic the Volt's behavior.
1


Right, I posted that chart several times before on the forum, and find the information contained therein quite useful. Thank you for referencing it! I could be wrong, but I believe that the 75% SOC might be close to 75% actual. Obviously, lowering the SOC from 85% (max) to 75% will prolong battery life and the expended energy will lower pack temperature temperature.

Losing up to 15% of EV range (10% delta SOC / 65% SOC total) in exchange for better battery life might an acceptable engineering tradeoff. If they brought down the SOC to 60%, that would correspond to as much as 40% loss of EV range due to cooling, assuming that the pack was fully charged at the beginning: 25% delta SOC / 65% SOC total = 0.38. How much energy would the TMS consume in 100F ambient per hour? Would 1 or 2 kWh be realistic?
 
opossum said:
That's funny. Our Leaf eats 7 temperature bars for breakfast!

Anyway...

Word today is that there's a car here right now at one of the Phoenix dealers that lost a second capacity bar. It's not our (drea / opossum, #0500) car, but I predict we will also join the 2-bar club very soon... unfortunately!
When you say "...at one of the Phoenix dealers...", that reminds me that most dealers will keep the demo car at 100% charge all of the time so that it is available for test drives. Those cars should show the worst degradation. So here's some advice: Don't buy a year old demo Leaf in a hot climate. :eek:

Yep, I'm following the "middle of the road, battery pack babies" and hope to be driving this car in 20 years with a 50 mile summer range.

Reddy
 
surfingslovak said:
I could be wrong, but I believe that the 75% SOC might be close to 75% actual. Obviously, lowering the SOC from 85% (max) to 75% will prolong battery life and the expended energy will lower pack temperature temperature.
Quick search reveals that "100%" is around 86% actual SOC leaving about 2.2 kWh unused at the top. Volt uses about 64% (10.3 kWh) of total capacity, which leaves about 22% (3.5 kWh) at the bottom. 75% of 10.3 kWh usable is about 7.7 kWh. 7.7 kWh + 3.5 kWh = 10.2 kWh / 16 kWh = 64%. So they stop cooling the battery when SOC reaches 64% total SOC assuming that by 75% they mean usable and not total capacity.
 
If they did, it would only likely accelerate the subsequent degradation as more of the extremes of the pack are used. The Volt has an advantage here as they use far less of the available capacity of the pack and thus could much more easily scale what is available as the pack deteriorates while still leaving a considerable amount of reserve capacity to minimize further pack deterioration.

nogajim said:
I wonder if Nissan will pull some kWhrs out of the hat sometime down the road. The battery is 24 kWhr, we are only using 21. If they provide access to some of that buffer it will be like swimming in that pool in "Cocoon," instant capacity rejuvenation!
 
drees said:
surfingslovak said:
I could be wrong, but I believe that the 75% SOC might be close to 75% actual. Obviously, lowering the SOC from 85% (max) to 75% will prolong battery life and the expended energy will lower pack temperature temperature.
Quick search reveals that "100%" is around 86% actual SOC leaving about 2.2 kWh unused at the top. Volt uses about 64% (10.3 kWh) of total capacity, which leaves about 22% (3.5 kWh) at the bottom. 75% of 10.3 kWh usable is about 7.7 kWh. 7.7 kWh + 3.5 kWh = 10.2 kWh / 16 kWh = 64%. So they stop cooling the battery when SOC reaches 64% total SOC assuming that by 75% they mean usable and not total capacity.
Right, absolutely. Interesting interpretation, but we still cannot be sure what the 75% reference really meant. Did you read the source thread? I believe that they they mention 85% or 86% SOC as full charge there. It would be logical if they continued that, and and SOC references were just that, and not percentages of usable capacity.

That said, 65% SOC would be obviously better as end point for TMS operation. It would more beneficial for battery longevity than 75% SOC, and losing up to 25% of usable capacity to battery cooling might be still an acceptable tradeoff. I like this reasoning, but we should just ask that question on the Volt forum, not sure how much more we can determine on our own.
1
 
surfingslovak said:
Right, absolutely. Interesting interpretation, but we still cannot be sure what the 75% reference really meant. Did you read the source thread? I believe that they they mention 85% or 86% SOC as full charge there. It would be logical if they continued that, and and SOC references were just that, and not percentages of usable capacity.

That said, 65% SOC would be obviously better as end point for TMS operation.
Yeah, hard to say exactly. Whether it's 65% or 75% true SOC, it's additional ammo to encourage delaying charging even to 80% in the LEAF (which is close to 80% actual SOC) when it's warm out. FWIW ~75% = 9 bars and ~65% = 8 bars on the LEAF.
 
2011 Nissan Leaf Battery Capacity Loss: Nissan Responds


By Nikki Gordon-Bloomfield

...“We’re aware of a few isolated cases where a very small number of consumers are reporting a one bar loss. (We’re talking less than 5 units versus the 12,000 on the road in the U.S.),” a Nissan representative told us.

Non linear loss.

In our original article, we told you that the Nissan Leaf workshop manual indicates the extinguishing of the first capacity light represents a 15 percent drop in battery capacity.

Losing that much capacity in the first year seemed drastic in the light of Nissan’s previous statements on battery life, but Nissan says battery capacity loss isn’t linear.

“In general, all batteries exhibit a higher loss of capacity early in life, but then the curve flattens over time,” we were told. “Our internal results indicate that the battery will have 80 precent of its capacity under normal use after 5 years, and 70 percent after 10 years.”...

http://www.greencarreports.com/news/1076847_2011-nissan-leaf-battery-capacity-loss-nissan-responds" onclick="window.open(this.href);return false;
 
"In our original article, we told you that the Nissan Leaf workshop manual indicates the extinguishing of the first capacity light represents a 15 percent drop in battery capacity."

“We can confirm that the state of charge[sic] is depicted as a non-linear scale but are not able to confirm the specific totals that each ‘bar’ represents,” Nissan’s official statement says.

Does this seem like a contradiction to anyone else? Seems like the official statement is unaware of what the service manual says.
 
edatoakrun said:
2011 Nissan Leaf Battery Capacity Loss: Nissan Responds
...“We’re aware of a few isolated cases where a very small number of consumers are reporting a one bar loss. (We’re talking less than 5 units versus the 12,000 on the road in the U.S.),” a Nissan representative told us.
I think we're around 10 so far just on the forum +who knows how many aren't on the forum...
 
drees said:
edatoakrun said:
2011 Nissan Leaf Battery Capacity Loss: Nissan Responds
...“We’re aware of a few isolated cases where a very small number of consumers are reporting a one bar loss. (We’re talking less than 5 units versus the 12,000 on the road in the U.S.),” a Nissan representative told us.
I think we're around 10 so far just on the forum +who knows how many aren't on the forum...
It would be very interesting to poll the Phoenix/Tucson Leaf owners. I followed a red leaf into a parking lot last week and had a chat about our cars. I asked him if he lost a capacity bar and he said he had, a while back. I asked if he is on the forum and he said he hadn't been since getting his car. Since I didn't look at his dash to confirm the dropped bar, i was reluctant to report it as another addition to the total.

I am beginning to wonder how Nissan expects to sell any leafs in Phoenix in the future.
 
2011 Nissan Leaf Battery Capacity Loss: Nissan Responds


By Nikki Gordon-Bloomfield

...“We’re aware of a few isolated cases where a very small number of consumers are reporting a one bar loss. (We’re talking less than 5 units versus the 12,000 on the road in the U.S.)
Well, we are aware of twice that number, which means there must be more (unless everyone who has this problem has reported it on this forum).

Losing that much capacity in the first year seemed drastic in the light of Nissan’s previous statements on battery life, but Nissan says battery capacity loss isn’t linear.
That would have been good information to put in the acknowledgment we all signed when we bought the Leaf. That may be common knowledge among battery manufacturers, but I only heard about it in the last few weeks. I suspect this is true of most other owners.

“In general, all batteries exhibit a higher loss of capacity early in life, but then the curve flattens over time,” we were told. “Our internal results indicate that the battery will have 80 precent of its capacity under normal use after 5 years, and 70 percent after 10 years.”...
So the Phoenix owners can be confident they will only lose 1% a year for the next 4 years? Does Nissan plan to do anything for those who lose more? Are these internal results based on accelerated testing, or actual live testing of a significant number of vehicles over time?

I must say, I am underwhelmed by Nissan's response. Nothing about what they plan to do for the affected "5 cases" (who were all told this is "normal"). Glad I live in a cooler area. I would be pissed if I had bought a Leaf and lived in Phoenix. I certainly hope they are right, but from a PR standpoint I give them a D- :( The brand is already slightly tarnished in my mind... but still glad I bought my Leaf and love driving it daily. :D
 
Stoaty said:
I would be pissed if I had bought a Leaf and lived in Phoenix.

That sums it up pretty well alright. I still have all 12 bars, but being in Phoenix, I'm not happy I bought
- and I'm really glad I just bought a Volt. I'm seriously thinking of trading in my 2011 and leasing a 2013. If they give me a hard time about having 11 capacity bars at that time, I'll tell them it's normal.

Someone else posted this in TickTock's original thread about AZ Lemon Laws. Anyone interested in pursuing this route?

http://www.bbb.org/us/Storage/16/Documents/BBBAutoLine/AZ-LLsummary.pdf" onclick="window.open(this.href);return false;

PROBLEMS COVERED
The lemon law covers any defect or condition that substantially impairs the use and value of the motor vehicle to the consumer. This is referred to as a nonconformity. The lemon law provides manufacturers with an affirmative defense if it can be shown that the nonconformity is the result of abuse, neglect, or unauthorized modifications or alterations of the motor vehicle.
 
That's what I would do! Nissan simply does not know what is going to happen or they would have prepared for this. I firmly believe they should only Lease in area's where they are seeing this and they should offer some kind of concession to buyers who experience more than say 30% loss in the first 5 years... they should not wait for this to happen but instead create a bright line to assure their customer base. Everyone who owns a Leaf or is thinking of buying a Leaf anywhere is going to look at how Nissan handles this as an example of what they can expect if for whatever reason, they end up in the same boat. Preserving consumer confidence is critical or a bunch of people will bail from the brand.

shrink said:
... I'm seriously thinking of trading in my 2011 and leasing a 2013. If they give me a hard time about having 11 capacity bars at that time, I'll tell them it's normal...
 
edatoakrun said:
2011 Nissan Leaf Battery Capacity Loss: Nissan Responds


By Nikki Gordon-Bloomfield

...“We’re aware of a few isolated cases where a very small number of consumers are reporting a one bar loss. (We’re talking less than 5 units versus the 12,000 on the road in the U.S.),” a Nissan representative told us.

Non linear loss.

In our original article, we told you that the Nissan Leaf workshop manual indicates the extinguishing of the first capacity light represents a 15 percent drop in battery capacity.

Losing that much capacity in the first year seemed drastic in the light of Nissan’s previous statements on battery life, but Nissan says battery capacity loss isn’t linear.

“In general, all batteries exhibit a higher loss of capacity early in life, but then the curve flattens over time,” we were told. “Our internal results indicate that the battery will have 80 precent of its capacity under normal use after 5 years, and 70 percent after 10 years.”...

http://www.greencarreports.com/news/1076847_2011-nissan-leaf-battery-capacity-loss-nissan-responds" onclick="window.open(this.href);return false;

My guess is this Nissan statement about only 5 is total BS. I'm willing to bet that there are at least a hundred and probably hundreds in the Phoenix area that have lost a bar or are close to it. Nissan actually knows how many so far based on the battery pack checks. They seem to be minimizing the total. Also, I don't believe we will have anywhere near 80% left after 5 years because when the 2nd bar goes that will be only 79% left and some have to be really close to losing the 2nd bar. In fact, we already know of at least one that has already lost it (based on an earlier post).
 
Nissan's attempt to obfuscate by painting this as a statistical anomaly is a big mistake, IMO.

I'll make my own prediction: Some Nissan LEAFs in Phoenix will be at or below 70% of original capacity after 2 years. We'll see how many Phoenix LEAFs are closer to that or Nissan's prediction of 10 years.
 
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