Care and feeding of the Nissan LEAF battery

by Ernie Hernandez on July 24, 2012

LEAF Battery Pack

Nissan LEAF Battery Pack

Or, Why it’s important to read the owner’s manual

A look at a very popular LEAF forum (mynissanleaf.com) will show that currently the most active topic is about the battery capacity loss of the LEAF. To clarify, we are talking about the traction battery, or the battery pack used to power the electric motor, as opposed to the 12-volt battery, which is used to power vehicle accessories. We have had many readers express interest in this topic and wanted our view on it. Our intent was to read through all of the posts, analyze them, and write a comprehensive article on the subject. When we started reading the posts, there were about 60 pages or 600 posts. It has since grown to over 1700 posts and counting. Our original plan was to read every post so we didn’t miss an important detail and then write up our review of the situation. However, given the rapid growth rate of the thread, we’ll start writing about this topic now in segments and update our series as we read more posts, and more information becomes available. That said, we choose to start our series on the care and feeding of the Nissan LEAF battery, as it became apparent upon reading the posts of the first several individuals that showed reduced capacity, that many had seemingly neglected to do so. Bear in mind that we don’t know what the charging routines and maintenance activities were for all individuals with battery capacity loss issues, but there was some commonality among the first five. But before we get to the battery capacity loss issue, we wish to take a look at the Nissan LEAF owner’s manual to see what Nissan recommends regarding battery care and maintenance.

As the current model is the 2012 Nissan LEAF we will use that owner’s manual as our reference.

Ambient temperature

In the EV Overview introductory section on Page EV-2 we find this notice:

Li-Ion Battery CautionUnfortunately, ambient temperature is something that an owner can do very little about, unless they choose to move to another location.

One significant change from the 2011 model year LEAF to 2012 was the inclusion of a battery heater as standard equipment. The battery heater is designed to maintain Lithium ion (Li-ion) battery output in extreme low temperature environments. Here is the notice regarding the Li-ion battery heater (Page EV-5):

Battery Heater cautionThe Lithium ion battery warmer uses electrical power from the Lithium ion battery when the charger is not connected to the vehicle. However, if it gets really cold where you live, leave the LEAF on the charger, otherwise the battery heater will not work if the Lithium ion battery charge falls below 30%.

Extreme hot temperatures, even for periods as short as one day, may impact battery capacity loss. The effect of extreme cold temperatures can be mitigated to some degree by the use of the on board Li-ion battery heater.

Li-ion Battery Life

Nissan notes over a dozen specific situations or operations that should either be avoided or performed to optimize Li-ion battery life. These are the specifics straight from the owner’s manual (Page EV-23):

NISSAN recommends you use the following driving and charging habits, where possible, to help maximize the battery’s useful life:

  • Avoid exposing a vehicle to ambient temperatures above 120°F (49°C) for over 24 hours.
  • Avoid storing a vehicle in temperatures below −13°F (−25°C) for over 7 days.
  • Avoid leaving your vehicle for over 14 days where the Li-ion battery available charge gauge reaches a zero or near zero (state of charge).
  • Allow the vehicle and Li-ion battery to cool down after use before charging.
  • Park/store your vehicle in cool locations out of direct sunlight and away from heat sources.
  • Avoid sustained high battery temperatures (caused, for example, by exposure to very high ambient temperatures or extending highway driving with multiple quick charges).
  • Use the normal charging or trickle charging methods to charge the Li-ion battery and minimize the use of public Fast Charge or Quick Charger.
  • Avoid sustained high battery state of charge (caused, for example, by frequently charging to 100% state of charge and/or leaving the battery above 80% state of charge for long periods of time).
  • Allow the battery charge to be below at least 80% before charging.
  • Moderate driving.
  • Use of ECO mode.
  • NISSAN recommends charging the batteries using the long life mode unless the vehicle is going to be driven a long distance. See “Charging timer” in the “CH. Charging”section.
  • If the vehicle will not be used for an extended period of time, charge the Li-ion battery using the long life mode once every 3 months. Do not operate the charging timer repeatedly while the charge connector is connected to the vehicle after the Li-ion battery charging is completed. Doing so may discharge the 12-volt battery. The power of the Li-ion battery can be checked on the Li-ion battery available charge gauge. See “Li-ion battery available charge gauge” in the “2. Instruments and controls” for details.

Before we go further, we understand that no situation exists where an owner would be able to accommodate all of Nissan’s recommendations. Some of these items, are in fact, beyond the control of the vehicle owner. We would like to point out a couple of things about this list. Although the first bullet point talks about high ambient air temperature, several points later Nissan cautions against sustained high battery temperatures. While intuitively it might seem that a black, unvented steel case would make for a very high battery temperature, there are other factors at play. First, the battery pack weighs about 660 pounds. This is very dense weight, as opposed to something like 660 pounds of feathers, which would weigh the same but take up quite a bit more room. What this means is that the starting temperature of the battery pack influences the ultimate temperature due to the inertia  involved. Kind of like turning an aircraft carrier moving at speed. It takes awhile to change course. The flip side of that is that once a high battery temperature has been achieved, it could take some time to cool down. Other battery temperature factors could include sustained aggressive acceleration or DC quick charging, which is why Nissan cautions against quick charging too often (Hat tip to Stoaty for the battery temperature info). Other points worth noting that can be controlled by the vehicle owner are the avoidance of sustained high battery state of charge (such as frequent charging to 100% or leaving the battery above 80% for long periods of time), and allowing the battery state of charge to fall below 80% prior to charging. The long life mode referred to recommends the use of the LEAF’s on board charge timer set to limit charging to 80%.

Our next article in the series will look at the first 250 posts or so, which encompass the first five owners to acknowledge publicly on the My Nissan LEAF forum the loss of one battery capacity segment. Future articles will take us further into the discussion and offer a look into some of the other owners that have experienced LEAF battery capacity loss.

As I finish writing this I see that Nissan has posted an open letter to LEAF owners on the MNL forum. We will include Nissan’s response to this issue, and our analysis of that response, in a future article.

{ 27 comments… read them below or add one }

indyflick July 25, 2012 at 2:26 pm

Excellent post Ernie! I saw that “Open Letter” from Nissan this morning and now I understand why it was disseminated. It seems to me that parking a LEAF in a Phoenix parking lot could be a big issue. If it’s above 100°F ambient temperature (normal summer day there), the parking lot could be over 130°F. On very hot days, they have measured asphalt temperature over 170°F in Arizona.

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Ernie Hernandez (LEAFguy) July 25, 2012 at 8:37 pm

indy – Thanks for the kind words. My inclination is to believe that there are two factors involved: 1 – Not reading the owner’s manual and understanding the requirements of proper battery life management and 2 – extraordinary heat. I have a lot of reading ahead of me.

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edatoakrun July 28, 2012 at 10:00 am

I believe that there COULD be at least one other significant factor in capacity bar loss.

There is SOME evidence, that some limitation on maximum charge MAY be set by the LEAFs battery management system. So it is possible, that the capacity bar display, and the GID and SOC reports from aftermarket capacity monitoring devices are showing, in part, that the BMS is limiting the charge level, to a lower percentage of the total battery capacity.

The LEAFs with lost bars may not have “lost” the entire amount of capacity indicated. The bar display may be indicating restrictions, either permanent or temporary, on the maximum percentage of the 24 kWh battery pack, that the LEAF BMS makes available, at “100%” charge.

The LEAF is designed to allow the Driver to use a very high percentage of the total battery capacity, generally believed to be about 94-95%, IIRC, but based AFAIK on observations only of cool climate LEAF Battery packs.

It would be poor planning, IMO, if Nissan has not designed the BMS to be adaptive, and limit charging under high-heat conditions, to help “fool-proof” the maximum charge level for hot-climate regions, where high SOC levels are believed to be most likely to lead to rapid capacity degradation.

Have fun wading through this overly long thread, Ernie.

Hope I’m not the bearer of bad news, when I tell you the near-hysteria on MNL, has led to plenty of other threads, on the same topic.

Looking forward to your further comments,

Ed

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Ernie Hernandez (LEAFguy) July 29, 2012 at 9:57 am

Ed, welcome to Living LEAF. Thanks for the encouragement. It will likely be a few days between each post as I have a day job to deal with also, but I’m sure that there is good information buried in all of it. I have seen some of the other topics already, but I’m not quite ready to take on 70 pages of posts on what Nissan should or shouldn’t be doing just yet. It amazes me that so many think that Nissan’s statement was too long in coming, whether they agree or disagree with it. Any large corporation making any product is going to look long and hard at a situation before putting a flag in the ground and making their position known. It’s not as if this battery degradation issue is life threatening. Yes, it reduces vehicle range (and by how much we don’t know. I’ve not heard of anyone testing that, but I’m sure that it will be done soon.) But I think this topic will be with us for months, if not years, as new battery chemistries are introduced and evaluated.

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Frank Twohy July 25, 2012 at 3:29 pm

Great job as usual! I was at a Nissan dealer in North County last week and was asked by the salesperson how I liked my LEAF. I told him I loved it but have been following the battery issue closely. He spoke up and said it was no problem as all you had to do was replace one or two bad cells. From what I read I don’t think that is the case. Perhaps you can enlighten guys like me in your future posts on battery health.

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Ernie Hernandez (LEAFguy) July 25, 2012 at 8:46 pm

Frank – thank you. At this point I think that the entire situation is so early in the game that it’s too soon to know what the end result might be. Nissan choosing to collect customer cars and examine these specimens to determine the issues is a huge step in the right direction. Data analysis will have as much to do with the outcome as battery cell analysis.

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Stoaty July 26, 2012 at 8:54 pm

Good article, but one sentence is inaccurate:

“Just as the interior temperature inside a closed automobile will be significantly higher than ambient temperature, so will the temperature inside the black steel battery case be significantly higher than ambient.”

In actual fact the closed case and thermal mass of the battery means that there is significant inertia in the battery pack temperature relative to ambient temperature. It is not unusual for me to go out at noon when temperature has risen to 80-85 degrees and find that I still have 5 temperature bars (maximum temperature for battery pack of about 75 degrees). So the battery pack can be higher than ambient, the same, or lower depending on the interaction of several factors:

–Starting battery pack temperature
–Length of time ambient temperature that is higher or lower than battery pack temperature has been maintained
–Heating of the battery pack from aggressive use of the accelerator
–Heating of the battery pack from L2 or especially L3 charging

I suggest revising the article to make this clearer.

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Ernie Hernandez (LEAFguy) July 26, 2012 at 9:29 pm

Stoaty,

Thanks for the input. I will edit my original article and reference your comment.

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Stoaty July 27, 2012 at 7:57 am

It would easier to read if you included the information from my comment in the body of the article (formatted or edited as you see fit)–rather than referring to a comment at the bottom–and just eliminated the crossed out sentence. I don’t need to claim credit (after all who is Stoaty???), just want to see things correctly described. At most, you could put in (Hat tip to Stoaty) in parenthesis.

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Ernie Hernandez (LEAFguy) July 27, 2012 at 10:44 am

Done. Thanks again.

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Neil Bettenhausen July 28, 2012 at 8:56 am

Another very informative post, Ernie. Thanks for posting.

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David Egan September 21, 2012 at 8:16 am

Hello Ernie.I’ve only got my leaf six weeks and my journeys are short and so far I have avoided the use of ECO drive.I estimate that I get 42 miles to a charge. That is an L2 charge from full to just where I do a mile or so into the reserve.It takes 4 hours and 20 minutes to charge to cut off point.I have no control over the cut off charge as the computer in the leaf decides that . Nissan says that it takes approximatly 8 hours for a full charge. I must therefore assume that Im only charging to 80%. I am slowly getting around to reading all the comments. Very informative. David

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Ernie Hernandez (LEAFguy) September 21, 2012 at 11:34 am

Hi David. I see where Nissan has changed their marketing message on the charge from empty to full. Nissan now claims seven hours from empty to full using a 240-volt charging station. In actual practice, I have never seen it take that long (even seven hours).

First, how do you know if you are charging to 80% or 100%? When you first start your car, if all 12 bars to the right of the distance til empty meter (says “miles” on the dash) light up, you have charged to 100%. If only 10 bars light up, you have charged to 80%.

If you have not set a charge timer on your car it is starting to charge as soon as you plug the charging station into the car. You can set the charge timer (if you wish) by pressing the blue “e” Zero Emission button to the lower right of the navigation screen. This will bring up your selection menu. You can select a 100% charge, or an 80% charge. You can set the charge to start and/or stop at any time you wish. As we have super off peak rates from midnight to 5:00AM, we set no start time, but we set the timer to stop at 5:00AM with an 80% charge. This is satisfactory for our daily use. We charge every night, and have an email set up to notify us upon charge completion. Our car usually reports charging is completed between 4:00AM and 4:45AM. If you wish to charge to 100% nightly, and you are not on any time of service plan, my suggestion is to set the charge timer to stop charging just prior to your normal departure time. Do not set a start time, as the car will select it based on how long it thinks it will take to charge. In this way you minimize battery state of charge time at 100% which will help preserve the life of your battery, but you are still assured of having a 100% charge prior to your departure.

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NorskeDiv May 12, 2014 at 8:54 am

“the blue “e” Zero Emission button to the lower right of the navigation screen”

Do you use this same button to set the emissions level for the Leaf, say if you want to use the HOV lanes in California?

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Ernie Hernandez May 16, 2014 at 6:39 pm

I’m not really sure what you mean by this. LEAF is a zero emission vehicle. Every LEAF qualifies for HOV lane use in California. There is no way to set the emissions level.

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Ranjan Dias Jayasinha June 23, 2015 at 6:39 pm

Hi, I live in SriLanka Colombo where the Day time Tempreture is always 32 Degrees Celcius . Night time it can Only Drop to 28 Degrees Celcius. Looking to park at Cool places in the Day Time is Not always possible in Colombo and outskirts. Hope to buy a Nissan Leaf soon. Now I am thinking whether to buy One or Not? Have I to wait until the New Battery Cooling system come to to Effect,! Please help me and Advice when to purchase. Also in SriLanka There No Charging Points fitted at places. So could I use the Normal Electric Plug Points to charge using Long Extension Wire! Awaiting a quick reply…… Please.

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Ernie Hernandez June 23, 2015 at 9:37 pm

Ranjan – Welcome to Living LEAF. In checking the Nissan Sri Lanka website (nissanlk.com), I see that Nissan does not currently sell the LEAF in Sri Lanka. If this is the case, my suggestion would be for you not to purchase a LEAF. If there is no manufacturer support for the vehicle, you will not be able to have it serviced, even for minor repairs or maintenance. Should you move ahead with your decision to purchase a LEAF, Nissan does not recommend using an extension cord with the charging system. My recommendation would be to wait until Nissan offers the LEAF for sale officially in Sri Lanka.

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Sandun Fernando November 14, 2015 at 8:51 am

Hi Ernie, very informative post.
Nowadays Leaf is the most popular EV in Sri Lanka. 2,700 Leaf registered in Sri Lanka so far. NissanLK does not sell Leaf due to Charging stations issue. We have a FaceBook group and the feedback are positive and enjoy riding this superb car. I have a question which Ranjan mention above, In my area Daytime temp is 30 Celcius and night 27-28 Celcius. I charge my Leaf @ night with 100% charge. Is this effect with battery life or health?
There is more than 2,000 Leaf imported and un-registered with Sales outlets.

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Ernie Hernandez November 14, 2015 at 11:20 am

Sandun – Welcome to Living LEAF. If you need the range of a 100 percent charge every day, then there is no problem charging to 100 percent. If you do not need the range of a full charge, charging to 80 percent, if your LEAF has that capability, could increase battery life. Any lithium ion battery will have a reduced life if charged to 100 percent and then not used. In other words, it is not bad for battery life if used soon after charging is completed. But if you don’t need the range of a 100 percent charge, it is better for battery life to charge to less than 100 percent.

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Ove juul July 19, 2015 at 10:04 am

Hi, Ernie
Let me see if I understand this correctly: If I leave my Leaf in the garage for 4 months while traveling, I should leave it not plugged in to the charger, left with a maximum
80 percent charge, and the 12 volt battery hooked up to a trickle charger? Thanks, Ove

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Ernie Hernandez July 19, 2015 at 11:29 am

Ove – Welcome to Living LEAF. Nissan recommends charging the Li-ion battery once every three months. If you will be gone for four months, you are exceeding that threshold. If you have CARWINGS, you could leave the LEAF plugged in with all charge timers turned off. At the three month interval you could remotely charge your car using the CARWINGS app. It would also be a good idea to trickle charge the 12 volt battery if gone for an extended period of time.

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Arthur Michaels December 28, 2015 at 11:01 am

What is meant by the phrase “long periods of time” in the statement, ‘avoid sustained high battery state of charge above 80% for long periods of time’?

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Ernie Hernandez December 28, 2015 at 11:19 am

Arthur – welcome to Living LEAF. Basically, days at a time. Any lithium ion battery, including those in your mobile phones and laptop, degrade at a faster rate if charged to high capacity and left unused. This is why the recommendation to charge to 80 percent. Early LEAFs, through 2013 I believe, had the ability to charge to 80 percent on the charge timer. This feature has now been removed to get a higher EPA range rating due to the EPA’s range calculation method. Also significant is the next statement: Allow the battery charge to be below at least 80 percent before charging. Frequent topping up charging of a highly charged battery is also counter to an extended battery life. A useful resource is batteryuniversity.com. Some of their most popular pages refer to lithium ion batteries.

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Stoatwblr January 25, 2016 at 11:10 am

(a different stoat)

I’ve been looking at acquiring a Leaf in Yangon for the incredibly congested downtown run. In general most round trips will be sub 20 miles.

Problem: in March/April it can easily top 45C in the shade (sun directly – and I mean _directly_ overhead), and pavement temps easily hot enough to fry eggs.
Even crossing the road at midday becomes difficult – the air at head level is still at 60C.

How well do Leafs handle this kind of thing? Any New Mexico/Arizona drivers who can weigh in? The car can be parasoled when parked but I have to wonder if some kind of forced ventilation is worth considering.

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Ernie Hernandez January 26, 2016 at 6:59 pm

Stoatwblr – Welcome to Living LEAF. Your round trip mileage will be no problem. Of more concern will be the life of the battery. High temperatures contribute to reduced battery life which will likely be a bigger factor for you.

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Ravi March 17, 2016 at 4:29 am

Hi Ernie,
I am living in Sri Lanka and used Nissan leaf 2014 model.
In my cause i charged the battery every two days at 100%. That amount is enough me to two days office travel.I start charging at 25 % and charge up to 100% at the night time.
(10 pm to 5 am).
My question is ,Is my charging pattern effect to the battery long life?
If yes,what is your recommendation?
Thanks and waiting your valuable advice.

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Ernie Hernandez March 20, 2016 at 4:40 pm

Ravi – Welcome to Living LEAF. Your battery charging behavior is fine. The only concern is charging to 100 percent and then not using it for an extended period of time. As long as you are driving it after charging to 100 percent you should be good.

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