rwherrick
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Re: 8 bar battery replacement metrics

Sun Sep 27, 2015 10:23 pm

Hey Guys,
I'm thinking of starting a new thread, but thought I'd run it past the group on this thread first, and see if I could get any insight.
Here's the issue: the "battery capacity monitor gauge" (i.e., how many bars of capacity it *says* you have left) is a lot more optimistic than my real-world experience. And Nissan seems to rely on it's bar programming exclusively for warranty claims, and I haven't heard anything about a bench-test being available. The annual battery test is pretty worthless. They just tell you how many bars (you could read this for yourself), and then give you a star rating (20/20 in my case). When you ask for special warranty measurements to be done, they say they don't have any equipment that can do that.
My highway mileage in normal driving at 65 mph is about 40 miles from a full charge to LBW, which is starting to get to the point where the car is at the edge of being much less useful. I did a test this morning on a flat course with climate control turned off and cruise control at 65 mph, and got 46.3 miles. So according to LeafSpy, it started at 15.7kWh with a full charge, and had 3.8kWh left at LBW (11.9kWh of usable margin, or 13.9kWh to VLBW). But even 15.7kWh / 24 kWh = 65.4%, or a fair way below the 70% for the Nissan Warranty. If you look at mileage and use the efficiency metrics the car gives in its economy meter, you would come to the conclusion that the capacity was a few kWh less than that. So I should be eligible for a warranty replacement, right?
No, not so fast. I just lost my third bar a week ago, at 41,200 miles and 4.5 years of use. I have 47.52Ahrs, 72.6% SOH, and Hx = 51.41. Since I heard SOH has to drop under 70% (or maybe under 66.25% to drop to 8 bars), and Ahrs below 43-44, it's not likely to happen in the next 6 months, when the 60 month warranty runs out.
So anyway, I'm surprised something as non-transparent as battery bar programming trumps any sort of benchtop testing of the battery capacity (either charging or discharging testing). It seems like you have to lose maybe a lot more than 30% of your battery capacity to qualify for a warranty replacement. Any comment on why the battery capacity monitor gauge seems more optimistic than other more objective indicators?
- Bob

P.S. - I leased one of the first 500 Nissan Leafs. I wouldn't have purchased it at the end of lease if I'd known the true battery status, or capacity loss I would see over the next year.

TimLee
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Re: 8 bar battery replacement metrics

Sun Sep 27, 2015 11:45 pm

rwherrick wrote:... But even 15.7kWh / 24 kWh = 65.4%, or a fair way below the 70% for the Nissan Warranty. If you look at mileage and use the efficiency metrics the car gives in its economy meter, you would come to the conclusion that the capacity was a few kWh less than that. So I should be eligible for a warranty replacement, right?
...
What you are getting wrong is that 24 kWh was total potential capacity.
But Nissan's software never allowed use of more than 21 to 21.5 kWh.
And that usable was from fully charged all the way down to Turtle which happens with 0.4 kWh remaining.
High Voltage Disconnect happens soon after at 0.3 kWh remaining.

Your nine capacity bars and AHr are similar to mine, although I have <30,000 miles on my 2011.
It is unlikely either of us will lose the fourth bar and be at eight bars for capacity warranty battery replacement before the five years expires.
With this amount of loss you really have to be prepared to drive to VLBW or the LEAF range is problematic.

Not sure where you are reading that SOH.
SOH is an integer value at top of page one in LEAF Spy Pro.
It is not % capacity.
% capacity is AHr divided by new capacity which is nominally thought to be 66.25 for a 2011.

Loss of bar four varies a lot.
Could be as low as bit less than 42 AHr.

Tim Lee
Chattanooga, TN

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keydiver
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Re: 8 bar battery replacement metrics

Mon Sep 28, 2015 7:30 am

Yes, unfortunately Nissan has thrown around that "70%" warranty number, when in fact it is much lower. For some owners, that 4th bar hasn't gone away until they are <66%, which can easily make the difference between a free warranty replacement and a $6000 out-of-pocket expense. :( As I have opined many times before, although the new capacity warranty is great for some of us, Nissan has deliberately set the threshhold so low that the majority of early adopters will never be able to avail themselves of it. I don't think it is possible, with only 6 months left on your warranty, and summer about over, but you could try driving it as much as possible, preferably at higher speeds to really heat up the battery, and then charge it to 100% as often as you can and leave it sit at 100% SOC.
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rwherrick
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Re: 8 bar battery replacement metrics

Mon Sep 28, 2015 8:33 am

Yes, unfortunately Nissan has thrown around that "70%" warranty number, when in fact it is much lower. For some owners, that 4th bar hasn't gone away until they are <66%, which can easily make the difference between a free warranty replacement and a $6000 out-of-pocket expense
Thanks Tim and KeyDiver. Hmmm. I'm surprised Nissan wasn't challenged on this point in the class action settlement. If 70% is really 66% or less, seems like there's ground for pressing a new class action lawsuit? I"m going to open a case with Nissan, and also look into what my options are for arbitration and appeal, assuming it's not going to get very far.
Tim, sorry, what are you saying is the final metric they're using to calculate 70% (or maybe less than 70%)? Does anyone know? Or is this purely empirical, where people can observe "no one who had a Ahr reading above x ever got a battery warranty replacement"? Seems like it should be based on kWh measurements, not "bar programming". As another friend who is a leaf owner liked to point out, "if we can't trust VW on emissions control programming, should we trust Nissan on battery bar programming?" ;)
- Bob

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Stanton
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Re: 8 bar battery replacement metrics

Mon Sep 28, 2015 8:46 am

rwherrick wrote: So anyway, I'm surprised something as non-transparent as battery bar programming trumps any sort of benchtop testing of the battery capacity (either charging or discharging testing). It seems like you have to lose maybe a lot more than 30% of your battery capacity to qualify for a warranty replacement. Any comment on why the battery capacity monitor gauge seems more optimistic than other more objective indicators?
This has been analyzed/debated for a couple of years now, but the bottom line is: there has to be some (idiot proof) way for the average customer (and Nissan dealerships) to easily determine when someone has met battery warranty conditions, and 8 capacity bars in the display is it. If it wasn't for the class action lawsuit we wouldn't have anything, but I can understand how you need something obvious, regardless of the car's "internal" readings, to determine when you have triggered the battery warranty.
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fooljoe
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Re: 8 bar battery replacement metrics

Mon Sep 28, 2015 12:23 pm

rwherrick wrote:Tim, sorry, what are you saying is the final metric they're using to calculate 70% (or maybe less than 70%)? Does anyone know? Or is this purely empirical, where people can observe "no one who had a Ahr reading above x ever got a battery warranty replacement"? Seems like it should be based on kWh measurements, not "bar programming". As another friend who is a leaf owner liked to point out, "if we can't trust VW on emissions control programming, should we trust Nissan on battery bar programming?" ;)
Seems like you've got it pretty well figured out: No, nobody knows exactly how Nissan's software determines when the bars drop, and I'm sure Nissan would guard this algorithm as a "trade secret" protected by the DMCA, which means it'd be ILLEGAL for any of us to even try to extract the code from our cars!

Worse, even though Nissan has said that its mandatory software updates (such as the infamous P3227 update) won't affect the bar loss thresholds, no one has been able to independently verify this. And unfortunately the VW lesson is clear that their software SHOULD be independently verified.

What we do know is that it's quite clear that bar loss happens well after the drop below 70% capacity, according to the only ways we have of measuring capacity (i.e. LeafSpy or other CAN readers.) I'm at 65% and still waiting for that bar to drop. :roll: Another way to measure your capacity loss (without LeafSpy) that I've suggested is to perform one or more "range tests": Reset your trip odometer and trip efficiency meter after a 100% charge, then drive all the way down as low as possible. You can return home after VLBW but I'd recommend then leaving the car on and using as much power as possible (running the defroster could help) until the car eventually hits turtle then HV disconnect. Make sure you're around when this happens, as the car will quickly drain the 12V battery after HV disconnect and you could be left needing a jump and/or damaging your 12V.

After HV disconnect, take a picture of your dash to note the miles driven and miles/kWh achieved, and divide to determine your available capacity. That number divided by the 21.5 usable capacity when new is the best way I know of to measure your capacity loss outside of LeafSpy (and I've found they do agree very well.) The reason I suggest doing this is it uses only Nissan's own instrumentation and no 3rd party devices of any kind.

Your suggestion that you'll open a case with Nissan is a very good one: History has shown that the "squeaky wheel gets the grease", as Nissan has been known to grant a few outside-of-warranty replacements to those who made a stink about it. Bring the car in complaining of range, and if you can document that with a range test like I described it couldn't hurt. But I'd expect anyone from Nissan to completely ignore any LeafSpy readings as a matter of policy.
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TimLee
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Re: 8 bar battery replacement metrics

Mon Sep 28, 2015 3:11 pm

rwherrick wrote:... If 70% is really 66% or less, seems like there's ground for pressing a new class action lawsuit? I"m going to open a case with Nissan, and also look into what my options are for arbitration and appeal, assuming it's not going to get very far.
Tim, sorry, what are you saying is the final metric they're using to calculate 70% (or maybe less than 70%)? Does anyone know? ...
Nissan executives confirmed at the dinner in August 2013 that the first bar is 15% and other bars are 6.25% which is also what was published in early version of the service manual.
Four bar loss is nominally 66.25% capacity compared to new.

But there has been no details provided on the specific parameters and algorithm used.
It clearly includes some time delay type parameters to avoid losing a capacity bar and then getting it back.

It is certainly an imprecise black box type indication.

Just sad that class action participants allowed such imprecision and did hardly anything to compensate the loss of a large % of the class.

Tim Lee
Chattanooga, TN

Man. Date: 03/10/11, VIN # 2026
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iamchemist
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Re: 8 bar battery replacement metrics

Tue Sep 29, 2015 6:12 pm

Fooljoe,

When you say that your battery capacity is at 65%, and you're still waiting for your (I assume the 9th) Capacity Bar loss, how long or how many full charges has your LEAF been at 65% or less of full capacity?

fooljoe
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Re: 8 bar battery replacement metrics

Tue Sep 29, 2015 10:08 pm

I'm at 43.2 Ah - crossed 44 about 2 weeks ago, so the "65%" mark is somewhere in there (about 43.4 Ah would translate to 65.49% of 66.25 Ah.) I drive about 55 miles 4-5 times a week, and lately that's a pretty near "full" charge.
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iamchemist
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Re: 8 bar battery replacement metrics

Sun Oct 11, 2015 2:01 pm

It seems to me that figuring out how the Nissan Battery Capacity Bar Algorithm actually works can not be insurmountable, if we consider a large enough body of data from lots of LEAF owners.

Fooljoe has stated that two weeks of LEAF charges, all below Nissan's published 66.25% bottom end of the 9th Capacity Bar did not cause that 9th bar to disappear from his display. Perhaps their is now more information on this particular case.

In my own experience (using a GID Meter for data and assuming 281 GID's for a 100% capacity new LEAF battery) my last 29 full charges have averaged 71%. The Nissan Published bottom end of the 10th Capacity Bar is 72.5%. Yet my 10th Capacity bar has not yet disappeared. I am wondering if perhaps the Nissan Algorithm is not based on an average at all, but instead counting the number of charges that are below (in my case) 72.5% with the start of counting being a full charge above 72.5%. If I take that approach, then my longest string of <72.5% charges is 9 charges. Perhaps Nissan wants 10 or 15 or more charges below 72.5% to remove the 10th Capacity Bar.

One thing that we can say for sure is that it is a TRAVESTY that we all have a LEAF battery warranty that is based on a unknown Nissan Algorithm. I am surprised such a thing is even legal! How do we even know if the Nissan Battery Algorithm is constant? What's to keep Nissan from making their Algorithm tougher, if their cash outlay for battery replacement gets higher than they want, and then downloading it to all of our cars? Essentially no one is "minding the store" in this situation.

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