Capacity Loss on 2011-2012 LEAFs

[surfingslovak]

It's unclear what the mappings will be, once that's rolled out.

My understanding is that the mapping will not change, and the software patch is supposed to make the gauge more accurate. Or less pessimistic, as Andy phrased it.

 

[mwalsh]

The assumption of 15% on the first bar based on the first shop manual has been widely referred to in this forum.

Well, I can tell you this much with certainty...the first bar is at the very least 11%, because that's what I have in verified degradation and (for now at least) still have all 12 capacity bars. So, yes, I continue to buy into the idea of 15% for bar one.

 

[cwerdna]

It's unclear what the mappings will be, once that's rolled out.

My understanding is that the mapping will not change, and the software patch is supposed to make the gauge more accurate. Or less pessimistic, as Andy phrased it.

Ok. Maybe you're right. It will be interesting to see if Nissan releases a mapping/puts it back in the service manual post-patch and to compare it to the one we know.

 

[HighDesertDriver]

The assumption of 15% on the first bar based on the first shop manual has been widely referred to in this forum.

Well, I can tell you this much with certainty...the first bar is at the very least 11%, because that's what I have in verified degradation and (for now at least) still have all 12 capacity bars. So, yes, I continue to buy into the idea of 15% for bar one.

We are in the same camp as Mike. The reported evidence of GIDS vs. Bars seems to suggest that the original table is valid.

Here's a related thought that I have not seen discussed: Why did Nissan place the Capacity Gauge "1" next to the 11th bar and not at the top next to the 12th bar?

 

[LEAFfan]

I'm not clear what you are questioning, the veracity of the table from the first shop manual or the reason(s) why it has been removed?

Please recall the capacity warranty, which was announced last year: three bars or 30%. If you assume that the shop manual table showed the capacity bars as Nissan intended them, then the the transition between bar three and four would correspond to 27.5 to 33.7% of rated capacity. If you assumed linear distribution of 8.33%, identical for all twelve capacity bar, which seems to be the most popular alternative interpretation, then the aforementioned transition would correspond to 25% to 33.33%.

Both alternatives would seem plausible, at least in theory.

Another thing to keep in mind is that it would usually take about a year for the first bar to disappear in Phoenix, but a much shorter time period for the second and third bar. The first bar typically goes at about 80% Gids. The second bar typically goes at about 73% Gids (LEAFfan please correct me if I got this wrong).

I believe that the evidence points to more capacity loss for the first bar, and less capacity loss for the second, third and fourth bar. Likewise, 15% for the first bar and 6.25% for all subsequent bars would not contradict the terms of the new capacity warranty.

Yes, that's correct.

 

[DaveinOlyWA]

The assumption of 15% on the first bar based on the first shop manual has been widely referred to in this forum.

Well, I can tell you this much with certainty...the first bar is at the very least 11%, because that's what I have in verified degradation and (for now at least) still have all 12 capacity bars. So, yes, I continue to buy into the idea of 15% for bar one.

+1 i let Steve Marsh borrow my meter for a few weeks and he has 12-13% degradation and still has all 12 bars so the first bar is AT LEAST 15% probably if not more...

 

[edatoakrun]

...The reported evidence of GIDS vs. Bars seems to suggest that the original table is valid.

Well, IMO, there is no evidence that that table is invalid.

There is, IMO, quite a bit of evidence that both gid counts and capacity bar loss reports are invalid, and over-reporting capacity loss in hot climate LEAFs, and also some evidence starting to accumulate that they may be under-reporting capacity loss in LEAFs driven in cooler climates.

 

[DaveinOlyWA]

...The reported evidence of GIDS vs. Bars seems to suggest that the original table is valid.

Well, IMO, there is no evidence that that table is invalid.

There is, IMO, quite a bit of evidence that both gid counts and capacity bar loss reports are invalid, and over-reporting capacity loss in hot climate LEAFs, and also some evidence starting to accumulate that they may be under-reporting capacity loss in LEAFs driven in cooler climates.

invalid is not the appropriate word i think. the chart is a guideline and is valid for a static set of circumstances. there is variance in readings caused by; voltages, capacities, ambient conditions etc which has been discussed at length. its funny how we forget the basics but whether we choose to consider them or not, the fact remains.

 

[surfingslovak]

Yes, which is why Andy indicated that they would like to make the capacity gauge more accurate, I believe. If you look at the table Tony compiled after the Phoenix range test, you will see that the capacity gauge over-reported the capacity loss he projected from the distance driven during the test for the majority of vehicles.

 

[DaveinOlyWA]

Hard to imagine expectinga different result since the test was run during "better than normal" conditions.

I think the degradation shown on the gauge is partially temporary and like the GOM, it does not the abilty to quantify itself as it relates t I the variances we live with

 

[surfingslovak]

Come again? I'm not sure what you mean by "better than normal conditions". I believe that the temperature-dependent nature of Gids has been well documented. It would appear that the capacity gauge depends on Gids at least to some degree, which might explain some of the delta observed. As to some of the capacity loss being temporary, I don't think that capacity bars have grown back. There might have been a case or two of a bar disappearing, and then coming back temporarily, and then vanishing for good.

I believe that energy measured from the wall is the best and easily accessible indicator of capacity changes available to an owner. Ideally, an owner would run the battery down to the very low battery warning or to turtle, recharge to full at home, note the temperature and the kWhs pulled from the wall. Then repeat this test at approximately the same temperature and in the same location after a few months. If the first measurement was done when the vehicle was new, this approach could give a fairly good estimate of the relative change in usable battery capacity.

 

[DaveinOlyWA]

The objective of the test was torun it at what is considered optimum for performance which is 70° which is not where these LEAFs live. Therefore if the test is run in better conditions, they should perform better.

Now whether or not it made a difference we dont know. What we do know is the results nearly across theboardexceeded our expectations so one conclusioncould be the error in the gauges

 

[surfingslovak]

I have several reasons to believe that the Phoenix range test was quite accurate. Tony did a great job with the test protocol. The most visible indicator would be that the results determined for two of the vehicles matched the numbers determined by Nissan in a bench test at Casa Grande in July with a good degree of accuracy. While the batteries were at 80 degrees instead of 70 degrees, the difference we would expect is relatively small (1% per 8F). All this has been discussed at great length before here and elsewhere, and I'm surprised that there are still so many questions.

Note that I started measuring wall energy in my LEAF last December and saw steadily declining numbers, which would match my real-world range pretty well. The Gid count was less conclusive over the same time period. I continued this practice with the ActiveE, and I'm convinced of the veracity of this approach.

The capacity gauge in the LEAF, like many other instruments in the car, can be inaccurate. This does not mean that the table published in the first shop manual did not depict what Nissan's design intention was for this gauge. The subsequent removal and the announcement of the new warranty along with the desire to improve instrument accuracy do not necessarily mean that the mapping will change, or that the first bar is not supposed to indicate 15% and subsequent bars 6.25% capacity loss.

 

[derkraut]

Uh....Do you have documentation from Nissan verifying the above assertion? Or, is this just a "guess" on your part? IMHO, this forum suffers more with each passing day from posts based upon conjecture rather than fact.

You really have to ask that question?.. you have been in this forum for a long time

I guess I'm not very perceptive. I was simply asking whether Nissan has issued/published a document stating that 15% of battery capacity has been packed into the first bar. If so, I certainly haven't seen it??? :?

 

[Volusiano]

I was simply asking whether Nissan has issued/published a document stating that 15% of battery capacity has been packed into the first bar. If so, I certainly haven't seen it??? :?

Yes, Nissan published this table in their first version of the LEAF service manual. I heard that they took out the table in later version of the manual (probably because the table made them look bad). The service manual doesn't come with the LEAF. You have to buy it separately.

 

[DaveinOlyWA]

I have several reasons to believe that the Phoenix range test was quite accurate. Tony did a great job with the test protocol. The most visible indicator would be that the results determined for two of the vehicles matched the numbers determined by Nissan in a bench test at Casa Grande in July with a good degree of accuracy. While the batteries were at 80 degrees instead of 70 degrees, the difference we would expect is relatively small (1% per 8F). All this has been discussed at great length before here and elsewhere, and I'm surprised that there are still so many questions.

Note that I started measuring wall energy in my LEAF last December and saw steadily declining numbers, which would match my real-world range pretty well. The Gid count was less conclusive over the same time period. I continued this practice with the ActiveE, and I'm convinced of the veracity of this approach.

The capacity gauge in the LEAF, like many other instruments in the car, can be inaccurate. This does not mean that the table published in the first shop manual did not depict what Nissan's design intention was for this gauge. The subsequent removal and the announcement of the new warranty along with the desire to improve instrument accuracy do not necessarily mean that the mapping will change, or that the first bar is not supposed to indicate 15% and subsequent bars 6.25% capacity loss.

we are getting off the track here. i am in no way disputing the results or methodology of the tests. only thing I could even think to add is that multiple runs would have been better but logistically impossible without devoting MUCH more time to it.

i only think that the gauges use parameters to spit their figures based on several different things and one "appears" to be heat and cold. there has been a few people who state they gained GIDs when the weather cooled off. now whether those gains actually resulted in increased ranges or any type of permanent capacity recovery, I dont know and in the grand scheme of things, doesnt matter unless one plans to move.

the other thing is the accuracy of the gauges. i dont think there is any "math errors" or calculation errors. just an unknown set of seemingly narrow and inflexible guidelines that do not take into account the various conditions the LEAF must endure.

what i really see is a ton of back and forth over the accuracy where some say its great, some say its way off and others dont know what to say because they see a lot of conflicting results. imm, we are all probably right to some degree and its the variability of our conditions and the gauges inability to interpret that variability that is creating the confusion.

now measuring power from the wall can be a better way to determine capacity but is still not foolproof because it is still temperature dependent so a slower charge has more overhead due to static charge being used to run the pumps, etc.

in an unrelated topic, I used the Tumwater QC and will be sending out queries but i am almost convinced that I suspect the charge rate has been lowered.

i plugged in today and ended up charging 10 minutes longer than i expected to. now, i know the charge rate is slower if the batteries are colder but today was fairly mild and i pulled in with 5 TBs...

 

[surfingslovak]

Yes, I appreciate your observations, and the efforts you and others have put into this. It's time-consuming and battery capacity is bit of a moving target. That said, I hope we agree that we are getting into a hair-splitting territory. It's unlikely that anyone will be able to determine their usable battery capacity down to 0.1%. But as long as some general guidelines are followed, and owners are aware that temperature plays a big role in all this, we can get a fairly good approximation. I would consider any homegrown method, which determines usable battery capacity with an accuracy within 1 or 2% of what would be obtainable in the lab, as resounding success.

I used the Phoenix range test because I thought that it was well-accepted, the outcome was fairly accurate, and within the aforementioned error tolerance. I did this to demonstrate that while the capacity gauge might not be perfect, the design intent might very well have been 15% for the fist bar and 6.25% for subsequent bars. While the effects of temperature and individual variance across different vehicles have been observed, there is nothing that would conclusively show that the aforementioned calibration of the gauge is incorrect. The 2011 shop manual spoke a clear language, and there is nothing that would contradict that in a meaningful and material way.

I believe that we could argue about this forever, and that's one of the reasons why this thread is over 500 pages long. Agreeing on 21 kWh usable battery energy was not a small feat either. Having a plausible and practical set of assumptions we can operate on is very important. Obviously, this does not mean that they should not be revisited when new data or new evidence comes to the fore.

 

[DaveinOlyWA]

I used the Phoenix range test because I thought that it was well-accepted, the outcome was fairly accurate, and within the aforementioned error tolerance.

agreed 100% and i never disputed the 15%. as mentioned TaylorSF has 12-13% degradation per GID count repeated a few dozen times and still had 12 CPs

 

[derkraut]

I was simply asking whether Nissan has issued/published a document stating that 15% of battery capacity has been packed into the first bar. If so, I certainly haven't seen it??? :?

Yes, Nissan published this table in their first version of the LEAF service manual. I heard that they took out the table in later version of the manual (probably because the table made them look bad). The service manual doesn't come with the LEAF. You have to buy it separately.

Thanks for that information, Volusiano. I stand corrected, and I apologize for questioning the accuracy of your original statement.

 

[JPWhite]

Just read this article regarding advanced degradation in Japanese Taxi's

http://www.greencarreports.com/news/1082483_japans-electric-taxis-falling-out-of-favor-with-drivers

Wonder what Nissan will do to resolve this issue?