Some Leaf Owners Experience Early Capacity Loss

5 years ago by Marc Lee 6

 

The Volt and the Focus Electric both feature active liquid heating/cooling loops to maintain optimum battery temperature. The Nissan Leaf uses only air cooling to keep the traction battery from overheating. Some were surprised at this decision and Nissan has been questioned sharply about it, but Nissan has insisted that air cooling is sufficient for the climate of the United States. Now come indications that some Leaf owners on MyNissanLeaf.com are seeing significant battery capacity degradation, within the first year of ownership.

Poster, Azdre from the Phoenix AZ wrote:

In the last few weeks, we’ve lost one of the ‘available’ bars (see picture). We’ve put 17,000 miles on it in 14 months. I immediately called the dealer, and he said it’s normal, we’d lose one bar and then won’t lose any more, and he’s seen it in cars with only 6 months of use. He’s had Nissan Engineers evaluate it and it’s ‘normal’. Battery test from 3/28/2012 was normal, 12 status bars, 5 stars.

LEAFfan from the Phoenix Area responded:

The first bar gone means they have 85% battery capacity left. The first bar doesn’t disappear until you’ve lost 15%.

 

Just left of the "1" there should be another small white bar

There appear to be several people who are reporting significant capacity loss within the first year. To be clear.  This is a very 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 and range estimate, which even Leaf owners who adore the car are calling the Guessometer.

Undoubtedly there are other people who are aware of capacity loss but are not posting about their experience so it is difficult to gauge how wide spread the problem may be. The post above suggests that the dealer has faced this issue before.

YOU CALL THAT A WARRANTY?

Nissan is confident that they can meet their warranty obligation with only air cooling. There is no doubt they can meet this obligation because unfortunately they do not appear to back up the traction battery with a meaningful warranty.

Nissan’s warranty stipulates only that the battery will deliver energy sufficient for the motor to achieve peak power. Critically, they do not stipulate for how long the battery will do this. Nissan uses the language that they warranty power performance, not battery capacity. I think it is fair to say such a warranty is worthless as far as range of the Leaf is concerned.

So predictably another poster who had complained to Nissan of a capacity loss that was between 12% and 20% in the first nine months, received a response from Nissan engineers that stipulated that the loss was normal. The owner was less than pleased.

Why the range? The 20% number was based on the range predicted by the car. The 12% number was based on an actual reading of the battery cells.

GM by contrast guarantees at least 70% of the original range through year 8. No word from Ford on what exactly their warranty is guaranteeing.

Garygid wrote :
You are the first on-forum report of a Loss of a Capacity Bar, I believe.

Down 15% is … disturbing to see it happen after just 14 months,
but you MIGHT have started with a low-capacity battery?

It looks like having access to an SOC-Meter, even before purchase,
would be a handy thing for us all.

This was typical of many which suggested that Leaf owners have their battery evaluated using a state of charge meter, either before or shortly after purchase, and to monitor it periodically to document any capacity loss. Towards this end, some users appear to be getting more accurate battery capacity information through the ODB port, and two devices appear to be in development to address this need. The Gidometer and the Leafscan. Frankly it is not clear to me what the point of documenting capacity loss would be since Nissan makes it clear they do not warranty capacity loss

KMP647 even went so far as to suggest:

Heat and high soc. not good these batteries.  We will see most battery issues in these warmest states, downside to the Leaf pack design.  If I lived in Phoenix. I would buy a focus or a volt.  Its very possible the battery was on the low end of the scale from the factory, no way to know unless you plug a GID meter into your Leaf when its new.

High heat and a high state of charge are key risk factors for capacity loss. And here again Nissan seems to have been less than cautious by allowing owners to charge to what it terms “100%.” What the actual SOC level that represents remains the subject of debate, but clearly it is a level that is sufficiently high that Nissan discourages its daily use and stipulates that capacity will be lost if it used daily. GM by contrast places no such restrictions on Volt owners because they protect the battery by only using 65% of its capacity. Statements from Ford make it appear that the Focus Electric will use about 85% of the capacity of its 23kwh battery.

A number of posters expressed a decrease in faith with Nissan for not providing a better warranty and for failing to address the concerns of those who have experienced significant capacity loss, while others owners worried what effect it would have on sales if people found out there have been problems and Nissan’s response has been “this is normal.” Other owners strongly questioned the charging, driving and vehicle storage habits of those posting with capacity loss. Implying that those who had lost capacity were themselves to blame.

Hopefully the number effected is very small, but that will be of little comfort for those caught by early capacity loss.

6 responses to "Some Leaf Owners Experience Early Capacity Loss"

  1. Open-Mind says:

    GM was clearly more conservative and cautious than Nissan with regard to battery life. This cost GM more money up front, to purchase extra engineering and extra battery capacity.

    Was GM too cautious, so they over-designed the battery?

    Was Nissan too carefree, so they under-designed the battery?

    Who made the best decision? We’ll know in few years.

  2. Marc Lee says:

    I solicited feedback at MNL. You can view that thread at

    http://www.mynissanleaf.com/viewtopic.php?f=30&t=8833&p=196870#p196870

    I have also posted my responses to that below.
    ________________________________________________________________________
    Thanks for the responses. I really appreciate the feedback, all of it. Have some that I would like to respond too specifically:

    Quote:
    “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.”

    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

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

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

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

    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.

    Quote:
    “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.”

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

    Quote:
    “Kubel: But it remains to be seen whether the battery issues are Nissan’s fault.”

    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.

    Quote:
    “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.”

    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 haunts the forums of MNL.

    1. Dave R says:

      There is no active cooling at all of the battery in the Nissan LEAF. Not even a fan. Cooling is completely passive. LEAFs with the cold weather package do have a few small heaters that will turn on in extreme cold to keep the pack from completely freezing, but even in very cold climates this would be rare – it would take several hours of cold soak.

      There is really only one thing one should do with the LEAF to maximize battery life:

      1. Don’t let the car sit with > 80% charge for any longer than you need, especially if the car will be seeing extended ambient temperatures over 85*F. Most lithium batteries will store best with them charged around 50% charged or so.

      Now – if you drive it daily and charge to 100% – it’s not such a big deal as typically you will charge to 100% in the middle of the night, let the car sit a few hours, then drive far enough in the morning to bring the SOC < 80%.

      What's really bad is charging it to 100% (actually about 94-95% of true total capacity) and let it sit there for weeks in hot weather. The LEAF's battery holds it's charge very well – you can leave it for a month and come back and you won't see any significant change in battery charge.

      That is one area where having active cooling is beneficial for 2 reasons:

      1. If the battery gets hot, it will cool it down which will extend battery life.
      2. If you store the car in warm weather not plugged in, it will use up charge to cool the battery which has the double benefit of reducing the SOC and reducing temperatures.

      Nissan makes it easy to minimize time the battery spends at high SOC – you can employ a few strategies:

      1. Charge to 80% instead of 100% using the timers. Many people don't regularly need the full charge, so this works for most people. This also has the benefit of being slightly more efficient – at 100% charge regenerative braking is turned off to keep from overcharging the battery – at 80% you get full regenerative braking as long as the battery isn't cold. And the last 30 minutes of a 100% charge tapers down, but the cooling pumps keep running the same speed so charge efficiency drops some in the last 30 minutes of a 100% charge.
      2. If you know you want/need full charge, it takes about 90 minutes to go from 80% to 100% if you hit the timer-override. Because of the tapering off that occurs in the last 30 minutes of a 100% charge, you get most of the 100% charge in an hour.
      3. You can set your charge timer with just an end-time. If you do this the car will automatically figure out when to start charging so that it will reach the desired charge level by the end-time setting. (Note that the LEAF is a bit optimistic and tends to finish about an hour before the end-time).

      Nissan outlines most of this in the owners manual. They definitely note that the car should be stored charged to 80% and that one should wait until the SOC drops below 80% before charging again.

  3. Marc Lee says:

    Here’s a quote from Volt Chief Engineer Andrew Farah relevant to this discussion:

    One disappointment is that the Volt and other Lithium-ion battery-powered electric vehicles may not be viable in hotter climates, such as some states in the American Southwest. Despite the fact that Volts will be sold in these states, performance may be significantly undermined due to the heat. Volt Chief Engineer Andrew Farah describes, “The Volt may not be right for everyone. If you live in the Southwest, depending on how you use your car, the Volt might not be right for you.”

    http://www.dailytech.com/Chevy+Volt+…ticle16969.htm

    thanks to ScottF for that quote and link…

    Even on the Volt which uses less of the battery, has liquid TMS and has stronger protocols to protect the battery in high heat, high SOC situation, GM acknowledges that it may not be suitable for every owner.

  4. John Hollenberg says:

    As of June 11, there are now 9 reported Leafs that have lost the first capacity bar. Looks like the Leaf really doesn’t like the temperature in Arizona.

  5. Mason says:

    The first TV news story on this broke in Phoenix Tuesday night. Nissan still has its head in the sand, denying that there is a true, across the board issue in hot climates. Anyway, here’s the link to the article, with the video of the story at the top… http://tinyurl.com/c8g9fzj