Some Leaf Owners Experience Early Capacity Loss

Would appreciate any feedback on this post:

http://insideevs.com/some-leaf-owners-experience-early-capacity-loss/

which was based largely on threads here such as:

http://www.mynissanleaf.com/viewtopic.php?f=30&t=8802


Marc Lee

Well, while concerns are valid, and this article is basically based on few forum posts, I don't get from where they got the idea that it is all because of battery air cooling...
I haven't seen any significant battery temperature fluctuations charging or driving.
And liquid cooling will not have any affect on battery life in storage scenarios, as it will not do anything if you park in 130F heat for example.
Basically instrumentation and battery warranty I think are the most controversial and not thought-through correctly by Nissan areas, and I hope Nissan will learn on first rollout of Leaf and will try to correct it.

As of how widespread the problem is... You can't get it by only reading negative experience posts in one forum...
I'm trying to collect some stats in survey about 1 year ownership of Leaf, so if anyone wants to participate please do, it'll take just couple of minutes http://www.surveymonkey.com/s/8QBVYGD
That would give some more or less good feel of how widespread the problem is if we will have enough participants.

An accurate portrayal of the situation. Not addressing this problem may hurt Leaf sales. Still very happy with my Leaf, but I live in a more temperate area, and have been very careful to avoid leaving the Leaf at higher SOC than I need, especially with higher summer temps.

Since I disagree with the direction of this thread, I guess I'll put in my 2 cents.

Looking at your website/blog (and your obvious Ford affiliation), I'd say this is a good example of how "too little information in the wrong hands can be dangerous". You have simply re-hashed an existing thread on this forum while attempting to sensationalize the subject with conjectures about air-cooling vs. liquid cooling (among other things). The fact is:
1) This owner clearly did NOT follow guidelines set forth by Nissan regarding charging with respect to (high) SOC levels and storage (they freely admit the car sat unused at near 100% SOC for a month)
2) It appears as though the owner has not brought this specific issue to Nissan (although they did get "dinged" on their annual battery report--which in and of itself is a rarity on this forum), so we don't yet know what Nissan will (or won't) do regarding the situation

With approximately 2 cases reported, out of perhaps 10,000 sold,
and all in AZ, I think, is really not that bad.

How many ICE-vehicle fires have there been in the last year?

It remains to be seen what the end of the second year willl bring.
So far, the LEAF really looks quite encouraging.

Unimpressive blog post.

I thought the blog post was fair, though it could have done more to show that it's not confirmed to be widespread. We can't stick our heads in the sand when it comes to the limitations and shortcomings of the battery technology as a whole, nor can we do the same with regard to the cost and weight savings thermal management choice that Nissan made with the LEAF pack being air cooled. If air cooling makes degradation due to temperatures more likely to happen, it needs to come out and be very clear to owners and potential buyers.

But it remains to be seen whether the battery issues are Nissan's fault. Part of me wonders if a FFE or Volt were stored at 100% SOC in 120F if its liquid cooling would be active and whether or not it would be able to save the battery any more than the LEAF.

As a consumer, I don't give any manufacturer the benefit of the doubt when there's an issue. If there's a problem, Nissan better do their part to show that it's an isolated incident, or is a result of something out of their control.

Of course, with all that said, I'm leasing and don't intend to buy out the lease now due to this and a number of other reasons.

1) Too much is unknown about the battery.
2) Too much is unsettled about the charging standards.
3) Too much is unknown about the residual value.
4) Too many features and improvements coming in the near future.

Jimmydreams said:

Unimpressive blog post.

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Yep, too much stew, too little oyster.

kubel said:

But it remains to be seen whether the battery issues are Nissan's fault. Part of me wonders if a FFE or Volt were stored at 100% SOC in 120F if its liquid cooling would be active and whether or not it would be able to save the battery any more than the LEAF.

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This is a very good point. Although Volt references were often not well received on this forum in the past, if nothing else, the vehicle is an interesting point of reference from an engineering perspective. If memory serves, the Volt will not charge its battery over 85%, presumably real SOC. If you unplugged the car, and parked it like that, the TMS will wake every half hour, and engage if the temperature of any cell was above 72F. This battery-powered cooling will stop once the SOC drops below 75%. However, if the Volt was plugged in, the pack will continue to be conditioned, regardless of the state of charge. You might want to review the Volt forum thread I've referenced below. I found Charles Whalen, the author of that post, to be very knowledgeable and resourceful. And to your question about how well this approach works: GM reportedly guarantees battery capacity to be at least 70% after 8 years or 100K miles.

Volt thermal management system temperature band?

Thanks for the responses. I really appreciate the feedback, all of it. Have some that I would like to respond too specifically:

UkrainianKozak: And liquid cooling will not have any affect on battery life in storage scenarios, as it will not do anything if you park in 130F heat for example.

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Actually no. In the Volt for example, if the car is left stored and the battery temp gets too high (above 120f if memory serves) it will run the liquid cooling loop until the SOC is about 50% to protect the battery. Do not know if the Leaf runs its fan until SOC is lowered to a safe level.

Also while I note that many MNL posters have criticized Azdre for leaving her car at 100% SOC for one month in May of 2011, a review of the weather for Phoenix AZ does not show temperatures approaching anything that should have been a problem. And of course the car is giving off charge just sitting so it would not have been at 100% very long.

http://www.wrh.noaa.gov/psr/pns/2011/June/MayClimate.php

Stoaty: An accurate portrayal of the situation. Not addressing this problem may hurt Leaf sales.

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Hey thanks. Definitely agree that not addressing this issue, IF it even is an issue is not good.

Kubel: I thought the blog post was fair, though it could have done more to show that it's not confirmed to be widespread.

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Thanks for the fair part, I really try to do that. I thought I had covered the not widespread part with this

“There appear to be several people who are reporting significant capacity loss within the first year. A small number but as some posters have noted there could be others who may not even realize that they have lost capacity in part because of the erratic nature of the battery gauge”

If the post left the impression the problem is widespread, then that was certainly a failing on my part. I will go back and edit to make that more clear.

Kubel :If air cooling makes degradation due to temperatures more likely to happen, it needs to come out and be very clear to owners and potential buyers.

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Bingo. That’s exactly what I was trying to get at.

Kubel: But it remains to be seen whether the battery issues are Nissan's fault.

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I agree 100%, it is NOT clear where the fault is here. And even if it is 100% the fault of the owner, this issue should STILL be highlighted so that others don’t make the same mistake.

Kubel: Part of me wonders if a FFE or Volt were stored at 100% SOC in 120F if its liquid cooling would be active and whether or not it would be able to save the battery any more than the LEAF.

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Yes the Volt would, see above. No clue how the FFE handles it, but since they have followed GM’s cue on battery supplier I’m guessing they will take the cue from GM on this as well.

My biggest beef is with the Nissan warranty. I cannot fathom why you would invest $4 Billion in a car and then back it with an empty warranty like that.

Thanks again for the feedback. I sincerely hope this turns out to be a non-issue. But if it is real I hope that discussions like these will highlight the need to educate future owners, many of whom will not likely be as technically grounded as those who haunt the forums of MNL.

surfingslovak said:

kubel said:

But it remains to be seen whether the battery issues are Nissan's fault. Part of me wonders if a FFE or Volt were stored at 100% SOC in 120F if its liquid cooling would be active and whether or not it would be able to save the battery any more than the LEAF.

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This is a very good point. Although Volt references were often not well received on this forum in the past, if nothing else, the vehicle is an interesting point of reference from an engineering perspective. If memory serves, the Volt will not charge its battery over 85%, presumably real SOC. If you unplugged the car, and parked it like that, the TMS will wake every half hour, and engage if the temperature of any cell was above 72F. This battery-powered cooling will stop once the SOC drops below 75%. However, if the Volt was plugged in, the pack will continue to be conditioned, regardless of the state of charge. You might want to review the Volt forum thread I've referenced below. I found Charles Whalen, the author of that post, to be very knowledgeable and resourceful. And to your question about how well this approach works: GM reportedly warranties battery capacity to be at least 70% after 8 years or 100K miles.

Volt thermal management system temperature band?

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excellent. Exactly the link we needed!

ChargedUp said:

Also while I note that many MNL posters have criticized Azdre for leaving her car at 100% SOC for one month in May of 2011, a review of the weather for Phoenix AZ does not show temperatures approaching anything that should have been a problem. And of course the car is giving off charge just sitting so it would not have been at 100% very long.

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The battery will lose very little capacity over a month, perhaps 1 or 2% SOC. Leaving it fully charged for an extended period of time is a bad idea, since this will disproportionally affect battery life. Just a small drop in SOC, from full to about 80% or 70% should help greatly, and will make the battery happy.

ChargedUp said:

If the post left the impression the problem is widespread, then that was certainly a failing on my part. I will go back and edit to make that more clear.

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The blog post will only be helpful if it highlights that we are only aware of a few isolated cases. It should be also clearly stated that Nissan has not confirmed this to be a problem. In the best-case scenario, one or two battery modules will be replaced, and the pack will be back to normal.

ChargedUp said:

Kubel :If air cooling makes degradation due to temperatures more likely to happen, it needs to come out and be very clear to owners and potential buyers.

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Bingo. That’s exactly what I was trying to get at.

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Indeed, clear guidelines and battery care clinics would go a long way. It would be even better if the vehicle allowed itself to lose some charge after a week of sitting at 100% SOC. Either that, or better warranty, provided that manufacturer guidelines are followed. It would be great if Nissan allowed a replacement pack to be prepaid, much like Tesla. Likewise, a comprehensive battery warranty could be an option owners will purchase. I believe that this is more of a business challenge, than an engineering challenge.

ChargedUp said:

UkrainianKozak: And liquid cooling will not have any affect on battery life in storage scenarios, as it will not do anything if you park in 130F heat for example.

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Actually no. In the Volt for example, if the car is left stored and the battery temp gets too high (above 120f if memory serves) it will run the liquid cooling loop until the SOC is about 50% to protect the battery. Do not know if the Leaf runs its fan until SOC is lowered to a safe level.

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Well, I have to agree, that the thermal management in Volt might be better, but I don't see how it relates to long term storage... Well, maybe very marginally
Long term storage at any SOC is bad in extreme heat, and Volt's system only manages heat until 75% of full, at which point it will be the same deal as leaf. So, if you compare Volt and Leaf when you charge them to 100% and leave in the middle of the desert for a month, Volt will perform slightly better by discharging the battery to 75%. If you leave the Leaf at 75% or lower, in the middle of the desert, Leaf will behave exactly as Volt... doing nothing.
If anyone has data how at high temperatures state of charge matters that would be helpful, I thought it is really bad to charge to 100% and then significantly cool the pack, that will cause overcharging. Not sure if heat is actually causing overcharge, or it is just bad for the battery at any level of charge...
On top of that during extreme cold it seems like Volt will not be heating up the battery, while Leaf with Cold weather pack will (while unplugged).
So, Leaf is marginally better during extreme cold, and Volt is marginally better in extreme heat. I'll agree to that.

BTW, I admit that I'm no specialist in Volt cooling system, but I had a feeling that it is just a loop through radiator, so it will not actually cool the battery if ambient temperature is high. Or will it actually run the AC?
I thought that it will do it only when the car is active (Sitting idling while turned on, or driving) and sometimes it even need to turn on the engine to help run the cooling/heating loop. I doubt that they engineered it in such a way that it will turn the engine on to run AC to help cool the battery in extreme heat wile it is sitting in your garage... I thought Volts liquid cooling is mainly just for heat dissipation, not actual cooling, in which case this will not help at all to bring the battery pack to the temperatures lower than ambient, even worse, because it will try to run something, pack temperature should actually increase a bit...

The cooling load will not raise the pack temp. It is silly to say the volt cooling is better if in most cases it is not needed in a LEAF and is not a benefit. The LEAF pack does not have a high power load and if it did it would need cooling. It is made out to be inferior at times when not compared properly as if it were a compromise based on the design. If the LEAF had a 120kw motor I would tend to say no water cooling could be big issue but it does not.

It's a silly argument, what if the LEAF had a 10Kw motor and nothing would raise the pack temp 1 degree then is it a better system over an non-water cooled one. No, it's different and perhaps simpler because it can afford to be by design, at least that is the stated intention of how they did it and they could not have done so with a higher motor load.

UkrainianKozak said:

Well, I have to agree, that the thermal management in Volt might be better, but I don't see how it relates to long term storage... Well, maybe very marginally
Long term storage at any SOC is bad in extreme heat, and Volt's system only manages heat until 75% of full, at which point it will be the same deal as leaf. So, if you compare Volt and Leaf when you charge them to 100% and leave in the middle of the desert for a month, Volt will perform slightly better by discharging the battery to 75%. If you leave the Leaf at 75% or lower, in the middle of the desert, Leaf will behave exactly as Volt... doing nothing.

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Well, how about this. You and I park our Leafs in Phoenix for a year. You will be at 100%, and I will be at 75%. We reconvene in one year, and compare notes. I hope you can afford the repair bill, ignorance tends to be expensive, at least in my experience.

There is very significant difference between 75% and 100% charge, and you can be sure that this was extensively tested. GM could have set a lower SOC limit, but they were likely looking for a tradeoff between decreasing the usable range, and increasing battery life. Few people would like to leave the office in the evening, only to find that their vehicle has lost 20% of charge just by sitting on the parking lot. I believe that Volt owners are supposed to leave their cars plugged in for long-term storage, in which case the pack will be conditioned and kept at 72F or below for maximum life.

You might want to review the following threads:

Optimal Portion of Battery to Use for Longest Battery Life?

Eight Tips to Extend Battery Life of Your Electric Car

surfingslovak said:

UkrainianKozak said:

Well, I have to agree, that the thermal management in Volt might be better, but I don't see how it relates to long term storage... Well, maybe very marginally
Long term storage at any SOC is bad in extreme heat, and Volt's system only manages heat until 75% of full, at which point it will be the same deal as leaf. So, if you compare Volt and Leaf when you charge them to 100% and leave in the middle of the desert for a month, Volt will perform slightly better by discharging the battery to 75%. If you leave the Leaf at 75% or lower, in the middle of the desert, Leaf will behave exactly as Volt... doing nothing.

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Well, how about this. You and I park our Leafs in Phoenix for a year. You will be at 100%, and I will be at 75%. We reconvene in one year, and compare notes. I hope you can afford the repair bill, ignorance tends to be expensive, at least in my experience.

There is very significant difference between 75% and 100% charge, and you can be sure that this was extensively tested. GM could have set a lower SOC limit, but they were likely looking for a tradeoff between decreasing the usable range, and increasing battery life. Few people would like to leave the office in the evening, only to find that their vehicle has lost 20% of charge just by sitting on the parking lot. I believe that Volt owners are supposed to leave their cars plugged in for long-term storage, in which case the pack will be conditioned and kept at 72F or below for maximum life.

You might want to review the following threads:

Optimal Portion of Battery to Use for Longest Battery Life?

Eight Tips to Extend Battery Life of Your Electric Car

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My point is that the margin with Leaf and Volt is that For leaf you have to think before you leave it for a year in heat, for Volt, you don't have to think. But For Leaf I know that the optimal charge for storage will be 50-60%, so I'd rather do that than leaving it at 100%, and at 50-60% of charge don't see any benefit between Leaf's and Volts system, besides that Leafs is simpler (less maintenance and less chance of breakdown), which is more important to me as a consumer... I'd rather have something simpler and cheaper rather then something more expensive and complex just in case I want to leave my car for a year on a parking lot in Phoenix while charged at 100%, which I know I will never do...
Bottom line is, I agree that Volts battery cooling system is technologically superior to Leaf's, but sorry, I don't need it... (I'm actually thinking about buying a Volt as a second car, and I'd rather have bigger trunk than advanced cooling system that is rarely used...)

UkrainianKozak said:

But For Leaf I know that the optimal charge for storage will be 50-60%, so I'd rather do that than leaving it at 100%, and at 50-60% of charge don't see any benefit between Leaf's and Volts system, besides that Leafs is simpler (less maintenance and less chance of breakdown), which is more important to me as a consumer... I'd rather have something simpler and cheaper rather then something more expensive and complex just in case I want to leave my car for a year on a parking lot in Phoenix while charged at 100%, which I know I will never do...

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Yes, absolutely, and I agree with this view. It was one of the reasons why I went with the Leaf as well, and didn't switch to the Volt later, although I was tempted.

UkrainianKozak said:

Bottom line is, I agree that Volts battery cooling system is technologically superior to Leaf's, but sorry, I don't need it... (I'm actually thinking about buying a Volt as a second car, and I'd rather have bigger trunk than advanced cooling system that is rarely used...)

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Indeed, and when the Volt fire, which was presumably caused by a battery coolant leak after the crash test, was national news, you certainly felt good about Leaf's simpler design. We can only speculate, but it looks like there could be a significant percentage of folks giving their vehicles less than ideal care, and ignoring some of the recommendations in the owner's manual. Let's hope that the design and the batteries are robust enough to deliver on owners expectations. Thankfully, we have not heard of too many problem cases.

ChargedUp said:

Do not know if the Leaf runs its fan until SOC is lowered to a safe level.

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Let's nip this in the bud..... The LEAF battery is NOT air cooled, or fan cooled. It is a sealed container; no air is exchanged. There is no fan to cool it.

Some of you need to forget about our AZ heat causing problems with the LEAF battery pack. If you leave it full in ANY city/state for a long time or top it off when it's above 80%, you will more than likely damage your pack.

LEAFfan said:

Some of you need to forget about our AZ heat causing problems with the LEAF battery pack. If you leave it full in ANY city/state for a long time or top it off when it's above 80%, you will more than likely damage your pack.

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LEAFfan, with all due respect, I'm getting tired of this nagging. Soon enough, we will have more data. I hope you are right, but let's just agree to disagree for the time being.

Lithium manganese battery calendar life.pdf