Nissan : Leaf’s Battery Pack Should Last As Long As The Car

LKK said:

If this is true it looks like Nissan's use of a simple air cooled battery thermal management system will pay off big time in terms of cost and reliability over those manufactures using the much more complicated liquid cooled systems.

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It's less expensive. And you get to keep a fifth seat. It is, however, hard to see the payoff, unless you think how losing 20% of your capacity over five years is better than losing it over eight years. Heat is certain to kill the battery, so if you live anywhere with hot weather the lack of a TMS will accelerate battery degradation. I could say I hope that isn't the case but it's inevitable so there isn't any point in pretending.

The lack of a TMS was a major reason why I never seriously considered buying. Nissan engineering understands the value of a TMS so I wouldn't be shocked to see one on Gen II.

SanDust said:

The lack of a TMS was a major reason why I never seriously considered buying. Nissan engineering understands the value of a TMS so I wouldn't be shocked to see one on Gen II.

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Otherway round - GM really wishes to have next gen LG battery that doesn't need battery cooling so that 5th seat can be added. Renault will also buy some of that, but not before LG improves their battery to be on par with Nissan's.

evnow said:

Otherway round - GM really wishes to have next gen LG battery that doesn't need battery cooling so that 5th seat can be added. Renault will also buy some of that, but not before LG improves their battery to be on par with Nissan's.

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You've said you think the Nissan battery is better than the LG Chem battery. Seems to me the chemistry is very similar. What makes you think the Nissan battery is better?

Of course everyone would love to have a battery that didn't need a TMS, but I don't see any current battery chemistry that is practical without it. Nissan is willing to forego the expense of a TMS knowing that this omission will result in replacing some battery packs. This is OK if people are willing to accept a battery warranty that applies to catastrophic failures and not much else, but if they demand a real warranty that guarantees the range then the cost-benefit proposition changes. People who are saying that "it's 120 degrees in my garage and my battery is just fine" are going to be in for a rude shock come year five or six.

AFAIK there isn't a lithium battery on the face of the planet that isn't adversely affected by heat.

Given the choice of storing the battery a various SOCs, which is best for battery longevity? :
80%? 50%? 30%?

Lets say you wanted to store the car for a month... Would it be best to set a timer for 80% SOC and just leave it plugged in the whole time?
Or if you could park it at 50% SOC and leave it there, would that be better? (assuming you could plug back in occasionally to recover any charge it lost from just sitting.)

SanDust said:

You've said you think the Nissan battery is better than the LG Chem battery. Seems to me the chemistry is very similar. What makes you think the Nissan battery is better?

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They don't need liquid cooling to be usable in an automobile. Try that with an LG battery.

TEG said:

Lets say you wanted to store the car for a month... Would it be best to set a timer for 80% SOC and just leave it plugged in the whole time?
Or if you could park it at 50% SOC and leave it there, would that be better? (assuming you could plug back in occasionally to recover any charge it lost from just sitting.)

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The consensus (in other threads) seems to be: leave it UNPLUGGED at around 50% SOC (or at least less than 80%). That also guards against things like power surges/spikes due to storms, loss of (house) power, etc. You can always check status via CarWings, although Nissan has it would take weeks before you'd see an appreciable loss in capacity (from sitting).

10000 miles with 326 charges gives an average of 31 miles per charge. Or at 4 miles/kWh about 7.7 kWh per charge. About 30% of the capacity. Maybe the battery does not have time to heat up at short rapid charges. 326 full rapid charges will have, most likely, a different impact.
It is still good to know that rapid charging avery 30-40 miles has little impact on the battery.

TEG said:

Given the choice of storing the battery a various SOCs, which is best for battery longevity? :
80%? 50%? 30%?

Lets say you wanted to store the car for a month... Would it be best to set a timer for 80% SOC and just leave it plugged in the whole time?
Or if you could park it at 50% SOC and leave it there, would that be better? (assuming you could plug back in occasionally to recover any charge it lost from just sitting.)

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Start at ~30% and set the timer to charge to 80% but only for one hour per week. Just to make it fun

Stanton said:

TEG said:

Lets say you wanted to store the car for a month... Would it be best to set a timer for 80% SOC and just leave it plugged in the whole time?
Or if you could park it at 50% SOC and leave it there, would that be better? (assuming you could plug back in occasionally to recover any charge it lost from just sitting.)

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The consensus (in other threads) seems to be: leave it UNPLUGGED at around 50% SOC (or at least less than 80%). That also guards against things like power surges/spikes due to storms, loss of (house) power, etc. You can always check status via CarWings, although Nissan has it would take weeks before you'd see an appreciable loss in capacity (from sitting).

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Thanks. Another angle, is I start at 80% each morning, drive to work, get there at about 50%, have no place to plug in, so it sits for 8+ hours a day at 50%, gets run down to close to 20% on the way back home, and starts a slow charge through the night.
So, on average it stays around 50%, and is basically at 50% the whole (hot) part of the day. Probably not too bad. I feel a little bad about dragging it down to nearly 20% on a daily basis, but such is life with a slightly long commute.

TEG said:

Thanks. Another angle, is I start at 80% each morning, drive to work, get there at about 50%, have no place to plug in, so it sits for 8+ hours a day at 50%, gets run down to close to 20% on the way back home, and starts a slow charge through the night.
So, on average it stays around 50%, and is basically at 50% the whole (hot) part of the day. Probably not too bad. I feel a little bad about dragging it down to nearly 20% on a daily basis, but such is life with a slightly long commute.

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I do more or less the same thing. Though I start at 100% and it sits at about 60% for the bulk of the day, getting me home with approximately 25% left (will know just how much with more accuracy once I get my SOC meter built).

TEG said:

Another angle, is I start at 80% each morning, drive to work, get there at about 50%, have no place to plug in, so it sits for 8+ hours a day at 50%, gets run down to close to 20% on the way back home, and starts a slow charge through the night.
So, on average it stays around 50%, and is basically at 50% the whole (hot) part of the day. Probably not too bad. I feel a little bad about dragging it down to nearly 20% on a daily basis, but such is life with a slightly long commute.

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Why do you feel bad taking it down to 20% on a daily basis? That shouldn't cause any problems.

Stoaty said:

TEG said:

Another angle, is I start at 80% each morning, drive to work, get there at about 50%, have no place to plug in, so it sits for 8+ hours a day at 50%, gets run down to close to 20% on the way back home, and starts a slow charge through the night.
So, on average it stays around 50%, and is basically at 50% the whole (hot) part of the day. Probably not too bad. I feel a little bad about dragging it down to nearly 20% on a daily basis, but such is life with a slightly long commute.

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Why do you feel bad taking it down to 20% on a daily basis? That shouldn't cause any problems.

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Just my personal sense about batteries from what I have read over the years. Just like Nissan discourages you from going over 80% SOC, I think it may be hard on the batteries to dip into the red bars. I cringe a bit every time I see someone go into turtle mode. But maybe I am over-reacting.

TEG said:

Stoaty said:

TEG said:

Another angle, is I start at 80% each morning, drive to work, get there at about 50%, have no place to plug in, so it sits for 8+ hours a day at 50%, gets run down to close to 20% on the way back home, and starts a slow charge through the night.
So, on average it stays around 50%, and is basically at 50% the whole (hot) part of the day. Probably not too bad. I feel a little bad about dragging it down to nearly 20% on a daily basis, but such is life with a slightly long commute.

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Why do you feel bad taking it down to 20% on a daily basis? That shouldn't cause any problems.

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Just my personal sense about batteries from what I have read over the years. Just like Nissan discourages you from going over 80% SOC, I think it may be hard on the batteries to dip into the red bars. I cringe a bit every time I see someone go into turtle mode. But maybe I am over-reacting.

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the conventionional wisdom discussed here in other threads is that Nissan does not let you get near the actual bottom of the battery pack, so you can't damage the battery taking it into the red. Though as a habit, it may have some nominal effect on battery life. From what I've read, 100% is actually close enough to 100% of the batteries actual capacity that unless you really need to use it, it's more ideal to stick with 80%.
g

Bassman said:

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Interesting that they can see battery capacity over Carwings. So why do we have to have a battery check if they can see the battery capacity via telematics?

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and what do YOU think telematics is for?? us?? well thanks but no thanks. i am guessing i do not have to provide the monumental evidence against the usefulness of Carwings to the consumer.

i always believed it was Nissan's way of collecting data for research AND ligitation purposes for any kind of warranty issue over battery degradation.

they know where you are going, how fast you are going and exactly how you treat your Leaf.

TEG said:

Just my personal sense about batteries from what I have read over the years. Just like Nissan discourages you from going over 80% SOC, I think it may be hard on the batteries to dip into the red bars. I cringe a bit every time I see someone go into turtle mode. But maybe I am over-reacting.

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I'm with you on this. Going too low is as harmful as charging close to full capacity. I like to keep the pack around 50% SOC and away from the sun if I can.

Unfortunately, Nissan does not disclose much when it comes to the battery. They either don't want to volunteer any data or are trying hard to keep things simple for the average driver. I think the jury is still out on their motives, but the dearth of information is deafening.

The best naive approximation I came up with is 16 bars representing the entire pack capacity, of which 12 bars are visible, two bars serve as low and very low battery charge warning, and the bars at the very bottom and the very top are not accessible for the sake of longevity. Should this be anywhere even close to reality, then the SOC would approach about 30% with 2 bars remaining on the dash. That's certainly low enough to consider an opportunity charge, but not low enough to harm the battery.

evnow said:

SanDust said:

You've said you think the Nissan battery is better than the LG Chem battery. Seems to me the chemistry is very similar. What makes you think the Nissan battery is better?

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They don't need liquid cooling to be usable in an automobile. Try that with an LG battery.

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The new generation of LG lithium ion batteries used in the Hyundai hybrids has improved, they only use air cooling.

evnow said:

They don't need liquid cooling to be usable in an automobile. Try that with an LG battery.

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So your claim that the Nissan battery is better is because Nissan doesn't have a TMS? By this reasoning any plane with an automatic landing system is flown by inferior pilots because otherwise the plane wouldn't need the additional safety system. And airbags in cars are a sign that the car is otherwise unsafe. Better engineering may just be better engineering or, I guess, that battery capacity is more important than a fifth seat or taking costs out of the car or waiting for the technology.

The claim that the Nissan battery is superior is interesting because, on the surface, the LC Chem battery appears more advanced. While both packs are basically LiMn2O4, the LG Chem battery does blend in some nickel and cobalt, which presumably we won't see in the Nissan battery until Gen II. We may get a quick take on this when we see how GM meets the CA AT-PZEV mandate next year. If it just extends the warranty then that will be a very strong indication that it's feeling quite confident that the LG Chem battery will outperform specifications. Or we may see some high extra warranty charges or other indications that the batteries will perform to and not above spec.

In any event what we won't see is what we're seeing from Nissan. Nissan seems to be walking back from its claims about battery longevity. When rolling out the car the claim was that the pack would have 70% to 80% of its capacity at the end of ten years. http://green.autoblog.com/2010/05/27/details-on-nissan-leaf-battery-pack-including-how-recharging-sp/ Now Nissan is saying five years. Big difference. Plus then the claim was that the main reasons for higher losses were high temperatures and a lot of quick charging. That seems to have morphed into the idea that charging to get the stated range will also result in losing capacity more quickly, which effectively means that all the claims about range should have been accompanied by an asterisk.

Either Nissan didn't understand its battery tech, which is somewhat disquieting, or it intentionally mistated things, which in my mind is worse.

My memory is a bit different.

From day one nissan claimed 20% after 5 years, 30% after 10.

I take that to mean most will do that. Some will be better some not. I am guessing they will do something about those.

Hopefully the data they are colllecting now will help them and others will better batteries

smkettner said:

FIVE years is the life of a car??? I am thinking 15 to 20 years is the life of a vehicle.
Usually there is lots of life left when I sell a vehicle in 10 to 15 years.

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In figuring out if the LEAF makes financial sense or not, I assume that it will depreciate to zero when it hits 100,000 miles on the basis batteries will be to costly to replace. Any residual car value will be cancelled by the hazardous waste disposal fee for the now worn out batteries.

10-15 years lifespan for a car? Yeah for an ICE.

The LEAF is brand new technology that will become obsolete as fast as you can spell it.

My financial estimates can be found at
http://jpwhitenissanleaf.com/2011/03/28/nissan-leaf-scrunching-the-numbers/

BTW My initial actual cost figures are within 1% of my estimates. Seems like my estimates were very close to reality, thanks to very accurate EPA data on the LEAF. I'll post an article/findings once I get to 1,000 miles which should be a good enough data sample. I'm only at 300 right now. Early/Mid September I should hit that landmark.

what it really boils down to is how much range or how little range can you accept? the Leaf's battery will not just drop dead one day (cant say that about a gas car!!). it will be a long slow decline which means that in 15 years you might have a range (Nissan adjusted LA cycle 100 miles) of 50 miles or 50%

how many people could not make that work? how many people could? in my present situation, 50 miles would be fine. it would still cover all my commuting and basic "around town stuff" but add to that the several hundred public charging stations i expect this area to have and then maybe the "sacrifice" might be so hard to swallow

right now, the Leaf takes care of slightly more than half our total transportation needs and could easily do 75% (but not allowing SO to drive that much!! her commute is 65 miles, mine is 14) so it could be a lot more useful than it already is. i still only charge on average 5 days a week. i still only hit the red bars a few times a month. but i still manage to put 1200 miles on it.

so if i continued that pace dropping to say 1000 miles a month after 5 years, 800 a month after 10. in 15 years i would have
over 200,000 mile on the Leaf. now, we all know that electricity will be more than 10 cents/kwh, but guessing gas will be higher as well and probably have increased more. but at today's rates, i am saving 5 cents a mile so that would be $10,000 in fuel costs saved and that would actually be more than that for most of us. i am comparing costs against my 50 mpg Prius. many here do not have that luxury. but also remember; the Leaf makes nearly all the short, in town, inefficient trips that the Prius had to share in the past.

my prediction is that current Leaf owners

40% will do nothing. they will simply drive it until the range is under 50 miles and then trade it in for another EV

30% will upgrade to a newer longer range battery pack in 3-5 years before they notice any real degradation of range and will probably pay a goodly amount for it


30% will sell the Leaf in 3-5 years for another EV...

now whether my predictions are close or not, one thing that is easy to notice and that is NO ONE will go back to gas