Warranty booklet doesn't say much about the Battery pack

[surfingslovak]

Well, if these are Nissan's battery experts deciding the fate of your pack, then I'm more than a little concerned. I can understand that it's difficult to get authoritative information inside of a large organization like Nissan, but this is going a bit too far. Given that they were not able to answer even the basics, I'm not sure how much trust I would put into the rest of their advice. Their customer service, while pleasant and engaging, has proven to be a bit disappointing. I have a feeling that all these folks will go through additional training and hopefully the Leaf will be available in greater numbers soon so that they can actually acquire hands-on experience with it.

Please have a look at the AESC website. It's sparse, but it has some of the data you were trying to source. Note that all of this is publicly available. Look for High energy module (for BEV):

http://www.eco-aesc-lb.com/en/product.html" onclick="window.open(this.href);return false;

Key takeaways, most of which have been posted on this forum (we really need an FAQ):

nominal cell voltage: 3.8V
nominal module voltage: 7.5V
nominal pack voltage: 360V

module: 4 cells (2 parallel and 2 in series)
pack: 48 modules in series

 

[Volusiano]

So, you better start saving for your next battery pack because in as little as 5 years your driving range could drop 20%.

The way I see it, right now most of us charge to 80% anyway to preserve battery life, and the 80% range has been proven adequate for many of us. So in 5 years, if it indeed drops to 20%, and we need the same range as we do now, we'll just have to charge to 100% to compensate and tack on the 20% range that we lost. Hopefully it'll buy us another 5 years this way before we truly have to consider replacing the pack anyway.

Also, within 5 years' time, the availability of charging stations in enough places also should help make the range issue more manageable.

And after 10 years, hopefully battery technology will improve and maybe cost less so we will have more options on how we want to replace our battery.

 

[surfingslovak]

In essence, yes. That's another reason to charge to 80% most of the time. Keep in mind however, that once you start charging to full, the battery will degrade faster. We don't know how much faster, but it's something to consider. I believe that Nissan has already announced greatly improved batteries for 2015, and I would expect them to be available before any of the current Leafs see appreciable reduction in range. If I were to hazard a guess, I would think that MY 2015 will see the first major overhaul of the Leaf, the introduction of the Infinity performance EV and a small delivery van they are allegedly developing.

 

[aqn]

I can understand that it's difficult to get authoritative information inside of a large organization like Nissan, but this is going a bit too far. Given that they were not able to answer even the basics, [...]

But were they not able to answer because they did not know the answer, or because they do not want to give you the answer?

I suspect that Nissan would know how, how much, and how quickly/slowly the battery's capacity degrades if they have done enough testing. However, that degradation might vary so widely and depend on so many factors that it's difficult to offer a warranty that covers all the bases and not expose Nissan to a big liability, so they punt and not warranty loss of battery capacity.

If capacity degradation was simple to measure/predict/quantify, other (eventual) EV manufacturers would offer a battery capacity warranty, and it would be highly stupid of Nissan not to offer one. (I'm not (yet) saying whether Nissan is stupid or not, or whether other EV manufacturers offer battery capacity warranty; I don't know.)

 

[surfingslovak]

But were they not able to answer because they did not know the answer, or because they do not want to give you the answer

That's a fair question. I can understand that they don't want to disclose anything confidential or something that would potentially translate to a class action lawsuit. What I alluded to were the simple things: nominal voltage per module, whether the modules are connected in series, etc. This is the type of information, which is now publicly available at AESC's website and I find it rather disappointing that Nissan's technical experts would not know that. I can understand if a CS person was not this knowledgeable however, and perhaps that was the point of contact the poster (electricfuture) has reached.

Overall, the information coming out of Nissan has been disappointing at best and they seem to change their tune as they go. That certainly does not sound reassuring and it does not earn them any brownies in my book. Don't get me wrong, I give them large credit for having the audacity to launch a vehicle like the Leaf and I believe that they have great engineering and operational talent at the company as well.

On a related note, if I remember correctly, an FAQ or a Wiki directly attached to the forum was suggested at some point. Did that get any traction? Are you seeing any contributors in your Wiki? I think that the Leaf community really needs an FAQ, especially in the light of the unsatisfactory customer service experience described in this thread.

 

[Stoaty]

He stated that only rapid battery heating or long term heating (leaving the leaf connected?) would negatively affect battery life. So, Level 2 charging to 100% should not significantly degrade the battery if you have it programmed to shut off in my standard 5 hour low cost time frame.

So he is saying that "Long Life Mode" (80% charge) is just marketing BS and has no basis in reality? I very strongly doubt Nissan would put that mode in and explicitly mention it in the manual if it didn't make a difference in battery life. I am sure Nissan has a lot more information than they are letting on, but apparently we are not going to be privy to that information.

 

[surfingslovak]

So he is saying that "Long Life Mode" (80% charge) is just marketing BS and has no basis in reality? I very strongly doubt Nissan would put that mode in and explicitly mention it in the manual if it didn't make a difference in battery life. I am sure Nissan has a lot more information than they are letting on, but apparently we are not going to be privy to that information.

+1

 

[JPWhite]

If capacity degradation was simple to measure/predict/quantify, other (eventual) EV manufacturers would offer a battery capacity warranty, and it would be highly stupid of Nissan not to offer one. (I'm not (yet) saying whether Nissan is stupid or not, or whether other EV manufacturers offer battery capacity warranty; I don't know.)

GM do have a capcity warranty. Time will tell which manufacturer is stupid.

GM have a pro-rated sliding scale in determining battery warranty eligibility and remediation actions. The following website has an excerpt of the warranty language issued by GM

http://nissan-leaf.net/2010/09/13/volt-battery-warranty/

It is similar to a pro rated warranty one might expect on tires or conventional batteries. I am somewhat surprised Nissan haven't been more specific, or try to match GM's warranty in more detail. The 8year/100,000 mile 'me-too' warranty doesn't cut it in my book. My guess (and hope) is that they will get more specific once they see real data coming in from the field and competitive pressure spotlights their warranty as less generous.

If Ford follow GM's lead, Nissan will be at a competitive disadvantage for sure, if Ford follow Nissan's example, GM may have stepped out too far.

Interestingly GM note 30% expected capacity loss at 100,000 miles, a number we've heard before about the Nissan battery packs. That at least is consistent and should form the basis of our expectations.

 

[surfingslovak]

That at least is consistent and should form the basis of our expectations.

JP, I'm afraid that you may not be taking couple of things into account. It's not quite apples to apples.

The Volt has a thermally managed pack, which runs approximately a preset 50% DOD cycle. The Leaf does not have thermal battery management of any kind and it gives access to up to 87% of rated pack capacity. We don't know what the typical usage pattern will look like for the Leaf, its owners have a higher degree of autonomy. The Volt does not offer quick charging either, but so far that has not been a factor, since we don't have any fast charging stations to speak of in the US. On the flipside, some people say that the Volt is harder on its battery, since it's effectively a hybrid.

Many people on this forum have been wondering about Leaf's capacity fade and wanted to quantify it one way or another. Unfortunately, our data is somewhat limited and most of us are not battery experts. I suspect that when Nissan says "expect 4% capacity fade per year", they are implying charging to 100%, full use of the available capacity, 25C ambient temperature, 12,500 miles of driving and no or only infrequent quick charging.

Obviously, we'll see a much wider mix of usage and environmental patterns and although Nissan anticipates that most of us will do better than the quoted projection, we don't know for sure. Nissan has been very vague about many aspects of their EV program, and it should not be too surprising if they don't tell us just how they came up with their magic wand number.

 

[Herm]

You must understand how GM did that, they simply lock away 35% of the battery capacity for future use when the car is new, then the Volt gradually starts to unlock that capacity as the car ages to maintain the 40 mile range spec. Nissan would simply reserve 8.4kwh when the car is new and open it up over the years. GM is a pretty savvy company.

This is one of the advantages of A123 batteries, long cycle life even if discharged 100%. BTW, I dont believe active cooling of the Volt's pack will extend its life in real life.. it would have to be plugged-in all the time for the cooling system to work to work continuously.. energy expense would add up if it does that during peak times.

 

[mdh]

That at least is consistent and should form the basis of our expectations.

JP, I'm afraid that you may not be taking couple of things into account. It's not quite apples to apples.

The Volt has a thermally managed pack, which runs approximately a preset 50% DOD cycle. The Leaf does not have thermal battery management of any kind and it gives access to up to 87% of rated pack capacity. We don't know what the typical usage pattern will look like for the Leaf, its owners have a higher degree of autonomy. The Volt does not offer quick charging either, but so far that has not been a factor, since we don't have any fast charging stations to speak of in the US. On the flipside, some people say that the Volt is harder on its battery, since it's effectively a hybrid.

Many people on this forum have been wondering about Leaf's capacity fade and wanted to quantify it one way or another. Unfortunately, our data is somewhat limited and most of us are not battery experts. I suspect that when Nissan says "expect 4% capacity fade per year", they are implying charging to 100%, full use of the available capacity, 25C ambient temperature, 12,500 miles of driving and no or only infrequent quick charging.

Obviously, we'll see a much wider mix of usage and environmental patterns and although Nissan anticipates that most of us will do better than the quoted projection, we don't know for sure. Nissan has been very vague about many aspects of their EV program, and it should not be too surprising if they don't tell us just how they came up with their magic wand number.

I hope Nissan will offer a sensible battery upgrade program down the road, because the car will be very limited for me with 20-30 percent less range.

 

[JPWhite]

That at least is consistent and should form the basis of our expectations.

JP, I'm afraid that you may not be taking couple of things into account. It's not quite apples to apples.

The Volt has a thermally managed pack, which runs approximately a preset 50% DOD cycle. The Leaf does not have thermal battery management of any kind and it gives access to up to 87% of rated pack capacity. We don't know what the typical usage pattern will look like for the Leaf, its owners have a higher degree of autonomy. The Volt does not offer quick charging either, but so far that has not been a factor, since we don't have any fast charging stations to speak of in the US. On the flipside, some people say that the Volt is harder on its battery, since it's effectively a hybrid.

Many people on this forum have been wondering about Leaf's capacity fade and wanted to quantify it one way or another. Unfortunately, our data is somewhat limited and most of us are not battery experts. I suspect that when Nissan says "expect 4% capacity fade per year", they are implying charging to 100%, full use of the available capacity, 25C ambient temperature, 12,500 miles of driving and no or only infrequent quick charging.

Obviously, we'll see a much wider mix of usage and environmental patterns and although Nissan anticipates that most of us will do better than the quoted projection, we don't know for sure. Nissan has been very vague about many aspects of their EV program, and it should not be too surprising if they don't tell us just how they came up with their magic wand number.

Thanks Surfings

That helps me understand the differences better. Essentially the end user (potentially) has a greater impact on battery life with a LEAF vs the Volt, resulting in less predictability regarding the LEAF battery life until more real world data is available. We are truly in uncharted territory, exciting and scary at the same time . Hopefully once enough data is in, Nissan will have a better idea of what driving and charging behaviors have the most impacts and can provide a more specific advice and hopefully build more safeguards into the product and warranties.

 

[Herm]

I hope Nissan will offer a sensible battery upgrade program down the road, because the car will be very limited for me with 20-30 percent less range.

The upgrade is called a new car

You should be good if you can charge to 80% and return home with one bar left... without recharging away from home.

 

[HighDesertDriver]

Many people on this forum have been wondering about Leaf's capacity fade and wanted to quantify it one way or another. Unfortunately, our data is somewhat limited and most of us are not battery experts. I suspect that when Nissan says "expect 4% capacity fade per year", they are implying charging to 100%, full use of the available capacity, 25C ambient temperature, 12,500 miles of driving and no or only infrequent quick charging.

Obviously, we'll see a much wider mix of usage and environmental patterns and although Nissan anticipates that most of us will do better than the quoted projection, we don't know for sure. Nissan has been very vague about many aspects of their EV program, and it should not be too surprising if they don't tell us just how they came up with their magic wand number.

+1

I think that surfingslovak has rightly stated "we don't know for sure." Nissan has made a giant leap fielding the Leaf, risking both corporate image and finances. However, like any company in a similar position, they have weighed the risks, and to their credit have decided to fish instead of cutting bait.

As launch customers, we have volunteered to share some of that risk for many different reasons -- "coolness", utility, free parking, HOV lane usage, saving the planet, poking OPEC in the eye, etc. -- and most owners are sending back real-world data via Carwings to help validate or disprove Nissan's expectations. It is reasonable to expect that Nissan has done their best through laboratory accelerated life testing and road testing to quantify their product, and if they are smart (and I believe they are) they will have reserved some margin when setting expectations for, in this case, battery service life. I'm certainly no battery expert and have absolutely no insider knowledge, but I do have experience with corporate risk analysis and personally expect Nissan's product in five years to retain better than 80% of its capability when new. Perhaps I will be disappointed, but if I am, I will not be devastated.

 

[surfingslovak]

The upgrade is called a new car

You should be good if you can charge to 80% and return home with one bar left... without recharging away from home.

I'd sincerely hope that it won't be this drastic. And you are right, if you charge to 80% most of the time and recharge at 3-4 bars if you can, cycling losses will likely be negligible. Something to the tune of a rounding error each year. The biggest factor will be calendar life, and if the report you found can be believed, this will be around 2.5% per year at a constant ambient temperature of 25C. I haven't had time to research it yet, but the climate in Nothern California is temperate and cooler than that for 5 or 6 months of the year. With little luck, we could be seeing capacity fade of around 2% per year in this region. There was also some speculation on the forum about hidden, or perhaps unrated pack capacity. I'm not sure how much faith I would put into that, but since Nissan is telling us precious little, perhaps there a possibility that they can mask part of the capacity loss.

What we do know is that they announced their next gen cells for 2015 and that they are building a large battery plant in Tennessee. I would fully expect them to provide replacement modules and perhaps even entire packs for some time to come. Hopefully, they will have the good sense to offer the new cells for the Leaf as well. I think I would rather trade in my 80 miles Leaf pack for a 160 miles one than plunk down $65K on a Tesla S or $30K for a new Leaf.

 

[electricfuture]

I am hoping we can keep the original packs rather than trade them in for the 150/200/300 mile packs as I intend to use the old pack to store solar energy and transfer it to the leaf at night through the DC quick charge plug.

Not to worry about costs - batteries will be more efficient and less costly before the Leaf pack needs replacement. Look at the Tesla S - a 300 mile range pack will be available next year. The car is the same size for either the 150/200/300 mile pack - just more efficient batteries. I strongly expect the same will be true for the Leaf in another 5-8 years but at a reasonable replacement price.

Remember what happened to lap top battery capacity? In only a few years capacity went from 2 hours to 6 and now the cost for lap tops is less.

Hummm - maybe Tesla is swithing from the 2 hour batteries to the 4 and 6 hour batteries to increase their range!

 

[Volusiano]

I am hoping we can keep the original packs rather than trade them in for the 150/200/300 mile packs as I intend to use the old pack to store solar energy and transfer it to the leaf at night through the DC quick charge plug.

Dream on! Nissan already stated they plan to reuse retired battery packs for similar purposes: sell them to power plants to store energy. So they're probably going to want you to turn the old one in.

 

[DaveEV]

The Volt has a thermally managed pack, which runs approximately a preset 50% DOD cycle. The Leaf does not have thermal battery management of any kind and it gives access to up to 87% of rated pack capacity. We don't know what the typical usage pattern will look like for the Leaf, its owners have a higher degree of autonomy. The Volt does not offer quick charging either, but so far that has not been a factor, since we don't have any fast charging stations to speak of in the US. On the flipside, some people say that the Volt is harder on its battery, since it's effectively a hybrid.

Couple corrections:

The Volt is using more than 50% - about 65-70%. The bumped up the usage to pick up some range rather than just use 50%.

Yes, under the same drive cycles the Volt is pushing their pack harder for the following reasons:

1. Volt weighs more - more power required to accelerate at the same rate.
2. Smaller battery capacity - this means that each cell is pushed at higher rates.
3. Smaller battery capacity - more depth of charge is used for the same trips (multiplied by 1 and 2).

Never mind that the Volt's motor will pull 120 kW from the pack - significantly more than the 80 kW the LEAF will pull.

The Volt pack is most definitely being pushed harder than the LEAFs. It's pack is also coddled a bit more.

I would expect capacity degradation to be similar on average. Perhaps better in hot climates thanks to it's pack cooling. Hard to say as the cell chemistries are different.

 

[surfingslovak]

The Volt is using more than 50% - about 65-70%. The bumped up the usage to pick up some range rather than just use 50%.
...
I would expect capacity degradation to be similar on average. Perhaps better in hot climates thanks to it's pack cooling. Hard to say as the cell chemistries are different.

Great data, thank you very much for clarifying that. Per statements from both Nissan and GM, this would translate to about 3.75% projected capacity fade per year for the Volt and 4% for the Leaf. These would be the numbers to beat. Can't wait for the first annual battery report, I wish I could pull the data out of my Leaf's VCM. Wasn't Ingineer working on a replica of the dealer scan tool?

 

[Herm]

Per statements from both Nissan and GM, this would translate to about 3.75% projected capacity fade per year for the Volt and 4% for the Leaf.

I have not seen those statements.. there was a simulation study posted that estimated 3% annual loss in a Leaf type BEV using lithium manganese spinel under the temperature conditions of Phoenix. They considered that as worst case.