8 bar battery replacement metrics

[TimLee]

...
I have LeafSpy Pro, but invariably choose to use the older version of LeafSpy Lite, and in that it's still shown as CAP(acity).

But you must be running an old out of date version.
The latest update v0.30.22 that was released Dec 2014 correctly lists it as SOH.

 

[mwalsh]

...
I have LeafSpy Pro, but invariably choose to use the older version of LeafSpy Lite, and in that it's still shown as CAP(acity).

But you must be running an old out of date version.
The latest update v0.30.22 that was released Dec 2014 correctly lists it as SOH.

Yes, as I said...older.

 

[iamchemist]

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.

If Nissan is using the Gid (or any metric we've used to manufacture the Gid) as part of their formula, 66.25% of 281 Gids is 186, and I've been under that for most of summer already. I also think my reported Gids have been higher than many in similar circumstances, and I don't seem to loose Gids as readily as some seemed to have.

Edit: I've been under 186 Gids since August 21st, which happened to be 43.44AHr. And incidentally LeafSpy was reporting that as 66.22 CAP.

It seems to me that there should be no question about "whether Nissan is using the GID". We are supposedly looking at Nissan's own digital charge capacity data here, regardless of whether you call it a GID or a Googleplex. No matter what you call it, the percentage calculation should still come out the same, provided you're using the same units for your current battery capacity and a new battery's capacity. However, there could be any number of caveats built into the algorithm. For example, perhaps full charges don't count unless ......! We just don't know - yet.

 

[iamchemist]

... And incidentally LeafSpy was reporting that as 66.22 CAP.

LEAFSpy reports SOH.
Was the 66.22 SOH?

Forgive my ignorance, but, if that 66.22 value is SOH (state of health) instead of SOC (state of charge), would that be a significant difference?

 

[fooljoe]

Forgive my ignorance, but, if that 66.22 value is SOH (state of health) instead of SOC (state of charge), would that be a significant difference?

SOH is a measure of capacity, i.e. what's the most you can cram into the battery, while SOC is "what percent of that capacity do you have in your battery right now?" Even when your battery is severely degraded you can still charge up to ~96% SOC, but that'll be 96% of a much smaller "tank".

Your point about the ridiculousness of the warranty threshold being based on some sort of "secret algorithm" is quite valid, notwithstanding whether the updates are OTA or not, as dhanson865 pointed out. They made us all get the P3227 update, after all, which not only could've changed how/when the bars drop but also cripples our cars in terms of available regen and whether they'll charge up all the way or now (and who knows what else.) With the recent VW scandal it just drives home the point even more clearly that Nissan can screw with us however they like and there's little to nothing we can do about it.

And to give an update on my particular situation, I'm still at 9 bars, with 43.0 Ah reported.

 

[mwalsh]

But you must be running an old out of date version.
The latest update v0.30.22 that was released Dec 2014 correctly lists it as SOH.

LEAFSpy Pro I have is version 0.35.59 and shows SOH to 2 decimal places. So the last time I used it, it showed 43.28AHr; 65% SOH; and Hx at 44.21. The LEAFSpy Free version I favor, except for when it doesn't do things i need that Pro does, is 0.26n9.

I'm also at 53AHr again today. But apparently climbing, not falling like fooljoe.

 

[iamchemist]

Forgive my ignorance, but, if that 66.22 value is SOH (state of health) instead of SOC (state of charge), would that be a significant difference?

SOH is a measure of capacity, i.e. what's the most you can cram into the battery, while SOC is "what percent of that capacity do you have in your battery right now?" Even when your battery is severely degraded you can still charge up to ~96% SOC, but that'll be 96% of a much smaller "tank".

Your point about the ridiculousness of the warranty threshold being based on some sort of "secret algorithm" is quite valid, notwithstanding whether the updates are OTA or not, as dhanson865 pointed out. They made us all get the P3227 update, after all, which not only could've changed how/when the bars drop but also cripples our cars in terms of available regen and whether they'll charge up all the way or now (and who knows what else.) With the recent VW scandal it just drives home the point even more clearly that Nissan can screw with us however they like and there's little to nothing we can do about it.

And to give an update on my particular situation, I'm still at 9 bars, with 43.0 Ah reported.

I understand what you're saying about the definition of SOH. GID Meters have a "Real SOC " feature that is not normalized. So you can calculate the real current capacity of your battery.

I believe that I recall from a previous post that 43 Ah should be the bottom end of the 9th Capacity Bar. How long has your LEAF been that way?

 

[fooljoe]

I understand what you're saying about the definition of SOH. GID Meters have a "Real SOC " feature that is not normalized. So you can calculate the real current capacity of your battery.

So that "Real SOC" would be your GIDs divided by the maximum GIDs on a new battery (I believe 281). "SOC" is really a misnomer for that, as is "capacity" - it's just an expression of the amount of energy in your pack relative to the usable capacity of a new battery. You could get something similar by taking the product of SOH*SOC.

I believe that I recall from a previous post that 43 Ah should be the bottom end of the 9th Capacity Bar. How long has your LEAF been that way?

I crossed 44 Ah on 9/5 and have been gradually falling to the cusp of crossing 43 Ah today (43.000006 at last reading). Mwalsh has done a great job of cataloguing known Ah values where people have lost the 9th bar, and the range is roughly 42-43.5, although I think at least one person was under 42 even. As far as what should be the bottom of the 9th bar, well that's another story...

 

[mwalsh]

^ 41.77AHr to 43.56AHr. I always felt that the owner at 41.77AHr must have been mistaken, but what do I know.

 

[iamchemist]

I understand what you're saying about the definition of SOH. GID Meters have a "Real SOC " feature that is not normalized. So you can calculate the real current capacity of your battery.

So that "Real SOC" would be your GIDs divided by the maximum GIDs on a new battery (I believe 281). "SOC" is really a misnomer for that, as is "capacity" - it's just an expression of the amount of energy in your pack relative to the usable capacity of a new battery. You could get something similar by taking the product of SOH*SOC.

I believe that I recall from a previous post that 43 Ah should be the bottom end of the 9th Capacity Bar. How long has your LEAF been that way?

I crossed 44 Ah on 9/5 and have been gradually falling to the cusp of crossing 43 Ah today (43.000006 at last reading). Mwalsh has done a great job of cataloguing known Ah values where people have lost the 9th bar, and the range is roughly 42-43.5, although I think at least one person was under 42 even. As far as what should be the bottom of the 9th bar, well that's another story...

So, based on the mwalsh values (bottom end of 9th bar at 41.77 Ah) you may not actually quite be there yet. At least that's more palatable than being at the bottom of the 9th bar for over a month, and it not dropping off your display.

 

[mwalsh]

So, based on the mwalsh values (bottom end of 9th bar at 41.77 Ah) you may not actually quite be there yet. At least that's more palatable than being at the bottom of the 9th bar for over a month, and it not dropping off your display.

The list as it stands right now is here. As you can see, it's really all over the place between the expected range:

http://www.mynissanleaf.com/viewtopic.php?f=44&t=12789&p=434825#p434825

 

[fooljoe]

So, based on the mwalsh values (bottom end of 9th bar at 41.77 Ah) you may not actually quite be there yet. At least that's more palatable than being at the bottom of the 9th bar for over a month, and it not dropping off your display.

Well obviously I'm not quite there yet, because the bar's still there! The point of my post is that this is not at all palatable (for anybody, not just me), as the range of reported bar losses catalogued by mwalsh corresponds to 63.0%-65.8% of new capacity (66.25 Ah), while Nissan has said that having 9 bars means you have at least 66.25% of new capacity.

 

[thankyouOB]

it has been awhile; can someone remind me of the requirements for warranty replacement of the original battery?
is it warranted for 60,000 miles over 5 years to retain at least 8 bars -- so i have until 2016?

i am about to go to just 9 bars any minute.

 

[kolmstead]

fooljoe, what makes the situation even less palatable is that Nissan announced verbally and in writing that the capacity warranty would kick in if capacity dropped to "less than 70%". Then they stated that the loss of the ninth bar would trigger the warranty. The original shop manual says will this will occur at a battery capacity of 66.25%

But since the mandatory P3227 update to make our capacity meters "more accurate", the ninth bar has been disappearing, on average, around 65.4%... 43.3 Ahr.

So I think that it is safe to say that a bunch of us are pretty pissed off. I understand that the Leaf Advisory Board has raised this subject repeatedly with Nissan upper management, with no positive results.

-Karl (64.7%)

 

[iamchemist]

it has been awhile; can someone remind me of the requirements for warranty replacement of the original battery?
is it warranted for 60,000 miles over 5 years to retain at least 8 bars -- so i have until 2016?

i am about to go to just 9 bars any minute.

The Battery Warranty in question reads "Nissan will repair or replace a Leaf's battery within five years or 60,000 miles (whichever comes first), if it loses more than 30 percent of its charge capacity. For Leaf owners, that means the warranty kicks in if the 12-bar battery (Capacity) gauge falls under nine bars".

According to published Nissan data, the 9th Capacity bar covers the range from 72.5% to 66.25% of new LEAF battery capacity.

 

[iamchemist]

So, based on the mwalsh values (bottom end of 9th bar at 41.77 Ah) you may not actually quite be there yet. At least that's more palatable than being at the bottom of the 9th bar for over a month, and it not dropping off your display.

Well obviously I'm not quite there yet, because the bar's still there! The point of my post is that this is not at all palatable (for anybody, not just me), as the range of reported bar losses catalogued by mwalsh corresponds to 63.0%-65.8% of new capacity (66.25 Ah), while Nissan has said that having 9 bars means you have at least 66.25% of new capacity.

No, actually that's not "obvious" at all. How do you know that half of your data wasn't recorded when the moon was not in the correct phase, and the unknown Nissan Algorithm takes phase of the moon into account in its calculations? Admittedly a very far out example, but you'll get my point.


On another note - would you or someone please remind me what the conversion is between Ah and GID's? That would be useful for those of us with GID Meters instead of a LEAF-Spy in following this conversation.

 

[fooljoe]

No, actually that's not "obvious" at all. How do you know that half of your data wasn't recorded when the moon was not in the correct phase, and the unknown Nissan Algorithm takes phase of the moon into account in its calculations? Admittedly a very far out example, but you'll get my point.

Just to make sure we're one the same page, the range of values catalogued by mwalsh is not the range of values representing the top to bottom of the 9th bar, it's the range where other people have lost the 9th bar, so the "bottom" of the 9th bar has been known to occur anywhere between 41.77 and 43.56 Ah.

So based on what we've seen I can expect to lose the bar any day now as I'm right in the "meat" of the distribution (42.9 today) - it'd be terribly unlucky if I get all the way down below 42 Ah before it happens. But based on what Nissan's said I should be terribly pissed that I didn't lose the bar months ago. Although realistically I might've waited out the summer before getting the new battery anyway, so things might work out ok for me. Mostly I'm pissed on behalf of everybody else who's about to or already has watched 5 years or 60k miles go by while they have somewhere between 63 and 70% of "real" capacity, but the mystical Nissan gauge still shows 9 bars.

On another note - would you or someone please remind me what the conversion is between Ah and GID's? That would be useful for those of us with GID Meters instead of a LEAF-Spy in following this conversation.

There's no clear conversion, since these are measuring different things. But it's been reported that the most GIDs you can get on a new 2011-2012 battery is 281, so 281 GIDs ~ 66.25 Ah. If the max you can charge to is 200 GIDs (remember this can bounce around a lot based on a number of things though), then you're at roughly 47 Ah (200/281*66.25). Although that's a very rough way to do it - I think Ah is a more consistent and reliable measure.

 

[sub3marathonman]

Just to make sure we're one the same page, the range of values catalogued by mwalsh is not the range of values representing the top to bottom of the 9th bar, it's the range where other people have lost the 9th bar, so the "bottom" of the 9th bar has been known to occur anywhere between 41.77 and 43.56 Ah.

Is there any record within the LEAF's data that has recorded, and could be retrieved later, the Ah when a bar has been been lost?

 

[dhanson865]

Just to make sure we're one the same page, the range of values catalogued by mwalsh is not the range of values representing the top to bottom of the 9th bar, it's the range where other people have lost the 9th bar, so the "bottom" of the 9th bar has been known to occur anywhere between 41.77 and 43.56 Ah.

Is there any record within the LEAF's data that has recorded, and could be retrieved later, the Ah when a bar has been been lost?

Not that we have access to. The data we get from ODBII changes every time you turn the car off/on and ass you drive. You can log it with your cell phone but the car doesn't offer any history.

 

[iamchemist]

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.

In discussing with a very EV Savvy friend about how might be estimating battery capacity at any given time, he suggested that one way would be for them to integrate Amps for a given time (thereby getting Ah), looking for the point at which the battery voltage drops a given amount (thereby essentially having a Ah vs. V plot), and then comparing that to the expected for a new LEAF battery. If that is true, then part of their Algorithm could be that no data are collected unless the battery is discharged for sufficient time during one charge/discharge cycle. If this is true, then a statement like "my last 10 charges have reach an Ah or GID value BELOW the bottom end of the 9th bar, and it hasn't dropped off" would be misguided. Perhaps most of those charges were not even counted by Nissan's Algorithm, due to insufficient discharge time before recharging. It's food for thought! Does anyone know how LEAF-Spy estimates capacity on a fully charged LEAF Battery?