Capacity Loss on 2011-2012 LEAFs

[turbo2ltr]

So it's been close to a month since I lost my last bar and I did another GID check. I'm happy to report I actually had 3 more GIDs at 100% than when I lost the bar the last time.

Here's hoping to seeing it level off.

BTW, the lost capacity has another side effect... more charge cycles. I've had to charge more often to do the car used to do on one charge, and for the first time, I quick charged the other day so I could complete my errands..

 

[EdmondLeaf]

It was a pleasure to meet and chat with PHX owners, hopefully there will be sensible resolution to battery capacity problem. This is not your problem - this is our problem. We all want Leaf to be a success, and want to help Nissan in Leaf marketing. I am very glad to hear that Nissan will be doing extensive testing of Leaf batteries so all of as will enjoy long years of gas free Leaf ownership. We are not immune to 100+ temperatures here too, and in fact during my stay in PHX weather was comparable what we are experiencing in OKC today

 

[thankyouOB]

well put.
we are in this together.

 

[DaveEV]

Interesting info, but remember that NCA means "Lithium Nickel Cobalt Aluminum Oxide" cathode, while the Leaf has LMO cathode which is "Lithium Manganese Oxide". Each battery chemistry has different characteristics, so what applies to one may not apply to another.

I agree - I was simply referencing the chart to use as a rule-of-thumb and rough guideline since all lithium batteries have similar curves - certainly do not take the data literrally.

how do you estimate gids without a meter?

I am basing my estimate on data I've collected driving from 100% to LBW or lower as well as using the time-to-charge from LBW or lower and comparing it to surfingslovak's reverse range chart.

and did folks get the meters from gary.

Gary is the primary source for GID meters, but I am looking to build one using lincomatic's Arduino design once I figure it out.

i need one, but would rather wait for ingineer's new gizmo, with the cool display and easy hook up.

Me too, but so far it's vaporware...

So it's been close to a month since I lost my last bar and I did another GID check. I'm happy to report I actually had 3 more GIDs at 100% than when I lost the bar the last time.

Here's hoping to seeing it level off.

Hopefully it sticks! What's your GID count now?

 

[DaveinOlyWA]

thankyouOB i would just ask to borrow a GID meter for a week (probably take that long to get a good handle on your capacity) you probably have someone in your area willing to part with it for that long

 

[surfingslovak]

cute kid, dave.
blessings.

+1!

It's interesting how much kids enjoy plugging in these cars. I think they get it much more than us adults.

So it's been close to a month since I lost my last bar and I did another GID check. I'm happy to report I actually had 3 more GIDs at 100% than when I lost the bar the last time.

Here's hoping to seeing it level off.

That's great to hear! I wonder if any seasonal effect on Gid readings will be confirmed come fall and winter.

 

[pchilds]

You have about 9% more to lose before you lose your first bar.

So, the first bar is 20% not 15%, I guess I miss or forgot reading that one.

 

[DaveinOlyWA]

cute kid, dave.
blessings.

+1!

It's interesting how much kids enjoy plugging in these cars. I think they get it much more than us adults.

He was born and raised on a plug. before the LEAF i drove a ZENN for 3½ years and it was a 2 seater so probably close to 70% of the miles was him and me and he loved that car because he could sit in the front seat but the best part is his confusion over why we never plug in the Prius. my response;

"Son, i am confused over why we dont plug in all cars too"

 

[DaveinOlyWA]

You have about 9% more to lose before you lose your first bar.

So, the first bar is 20% not 15%, I guess I miss or forgot reading that one.

its 15% for the first
6¼ % for each additional bar

 

[surfingslovak]

So, the first bar is 20% not 15%, I guess I miss or forgot reading that one.

Please remember that we can only read Gids, which is a coulombic measure of present stored capacity. We are unable to read the permanent degradation coefficient from the CAN bus with these meters. Although there are some theories and approximations, we are unsure how exactly these two relate to each other.

"Son, i am confused over why we dont plug in all cars too"

LOL

I will have to remember that one.

 

[Volusiano]

I don't blame people for wanting to plug in right away after they get home and charge to 80% between 9pm-12am. They want their car to be ready at full 80% capacity as soon as possible to serve them whenever needed.

I can see the psychology behind this - but at least personally in over a year of LEAF ownership - there has been zero cases where I've needed to go out again after getting home. And even if I did (and I suspect the vast majority of other LEAF owners as well), I have another car should I need the range.

I understand what you're saying if you're the sole driver of the car. But in my case, I have a family of 4 with 2 college-age drivers who live at home who go out and about at all times of the day and night. So that's why my Leaf is in high demand at all times and I want it to be the primary vehicle for use as much as possible for obvious reasons.

Nissan specifically stated that one shouldn't charge again until SOC is below 80%

Of course nobody is talking about charging again before SOC is below 80%. We're only talking about charging FROM BELOW 80% up to 80% here.

and that one should let the pack cool before charging.

but Nissan never specifies which temperature bar is considered cool for charging and which are not. If you look at the temperature bar display, the 7th bar, even 8th, 9th and 10th bars are all displayed as white bars. Only the 11th and 12th bars are displayed as red bars. So it's easy for somebody to consider the 7th bar to be not too hot for charging, based on the color of the bars. And don't forget that the 7th bar is only 1 bar above the half way point of all 12 bars. So Nissan's instruction to wait for the battery to cool down without specifying exactly which bar is cool is just playing safe to cover their *ss without having true intention to give helpful instruction to owners.

Now if Nissan had labeled the 8th bar and up as red (because the 7th bar can be seen fairly often in the summer time especially in Phoenix), then at least it's obvious that the 7th bar is very close to red, hence bad. But the fact that only the 11th and 12th bars are labelled red gives a false indication that the 7th bar is not THAT hot, therefore cool enough for charging.

I, for one, would not have become an early adopter if Nissan has disclosed all this stuff about waiting for the battery to cool down before charging, or that 80% charge stored all night long is bad, etc. There's a balance before too many charging requirements becomes a nuisance and not worth using. After all, people buy the car to serve them, not the other way around.

This was all disclosed before one received their car. But perhaps not quite as prominent as it should have been.

I already discussed the point about waiting for the battery to cool down before charging above.

But on your other point, please show me anywhere in the manual where it says that leaving the car stored at 80% SOC all night long is bad. I only see the part about not charging again if the car is above 80% SOC. But that's way different than saying that storing the car at 80% is bad. If Nissan doesn't say that, one can only assume that storing the car at 80% SOC all night long is safe.

 

[Stoaty]

But on your other point, please show me anywhere in the manual where it says that leaving the car stored at 80% SOC all night long is bad. I only see the part about not charging again if the car is above 80% SOC. But that's way different than saying that storing the car at 80% is bad. If Nissan doesn't say that, one can only assume that storing the car at 80% SOC all night long is safe.

Yes, but safe implies a binary or near binary choice (safe vs risky or unsafe). In actual fact, temperature and "high" SOC are probably on a continuum that goes from:

Optimal to
Slightly less than optimal to
Acceptable to
slightly increased rate of battery degradation to
Moderately increased rate of battery degradation to
Severely increased rate of battery degradation to
Extreme increased rate of battery degradation

Temperature is probably the dominant factor for SOC 80% or less... or perhaps not given the curves shown for storage at different SOC at different temperatures (but for NCA cathode, not our LMO cathode).

 

[DaveinOlyWA]

Yes, but safe implies a binary or near binary choice (safe vs risky or unsafe). In actual fact, temperature and "high" SOC are probably on a continuum that goes from:

5 TB;Optimal to
6 TB; Slightly less than optimal to Acceptable
7 TB; to slightly increased rate of battery degradation to
8 TB; Moderately increased rate of battery degradation to
9 TB; Severely increased rate of battery degradation to
10 TB; Extreme increased rate of battery degradation

Temperature is probably the dominant factor for SOC 80% or less... or perhaps not given the curves shown for storage at different SOC at different temperatures (but for NCA cathode, not our LMO cathode).

edited your post to add TB's after your chart THEN it turns red...

 

[Volusiano]

Yes, but safe implies a binary or near binary choice (safe vs risky or unsafe). In actual fact, temperature and "high" SOC are probably on a continuum that goes from:

5 TB;Optimal to
6 TB; Slightly less than optimal to Acceptable
7 TB; to slightly increased rate of battery degradation to
8 TB; Moderately increased rate of battery degradation to
9 TB; Severely increased rate of battery degradation to
10 TB; Extreme increased rate of battery degradation

Temperature is probably the dominant factor for SOC 80% or less... or perhaps not given the curves shown for storage at different SOC at different temperatures (but for NCA cathode, not our LMO cathode).

edited your post to add TB's after your chart THEN it turns red...

See, this is exactly what I'm talking about. Nissan should have had more detailed instruction like this in their manual, and made it a point to go over this with buyers if this is critical to battery longevity. But they don't. So they're misleading buyers by being wishy-washy and say enough to cover their butt, but not saying enough to give more facts to buyers. Same tactics they've been using regarding battery warranty.

My whole point was that Drees said he was shocked to see that not too many people use good charging practices from what he sees in the stats. My point is how are people supposed to know if Nissan chose not to divulge all the facts? You can't say that people are doing bad things to their battery if they don't know what's good and what's bad. And I'm not talking about 100% charging practices here. I'm just talking about 80% charge storage overnight and avoid charging when the battery is at 7 temp bar.

It's not people's fault that they're ignorant about this stuff. It's Nissan's fault for choosing not to educate them and keeping them ignorant.

 

[Volusiano]

I lost 1 bar since early June. Today I charged to 100% SOC, reset my miles/kwh reading, drove 53 miles with 2 bars and 11 miles left on the GOM, averaging about 4.7 m/kwh. AC was used the whole time. Temperature ranged between 104 and 95F during the trip.

So if I get 4.7 m/kwh for 53 miles, it means that I used up 11.3 kwh.
If I have 11 miles left on the GOM (I know, not accurate, but it'll have to do), that means another 2.34 kwh in my range.

So my roughly total available range is 11.3+2.34=13.64kwh.

The battery is supposed to hold 24kwh. Assuming that Nissan only allows people to tap 70% of this (I'm just guessing here). And I lost 1 capacity bar which is 15%. So supposedly, my battery should have 24*.7*.85=14.28kwh. That's still more than the 13.64 kwh I calculated above.

So a couple of questions:

1. Is the 70% I assumed above a good guess? If not, what should it be?
2. If I'm close to losing 2 bars, then what is the 2 bar capacity loss?

I'm just trying to compare the 13.64 kwh I calculated to see if it jives at all with the remaining capacity of my battery which had 1 bar loss back in early June. Right now, the 13.64 kwh number seems to fall short of what I should have gotten. So I'd like to know where I went wrong on my calculation? Thanks.

 

[DaveinOlyWA]

I lost 1 bar since early June. Today I charged to 100% SOC, reset my miles/kwh reading, drove 53 miles with 11 miles left on the GOM, averaging about 4.7 m/kwh. AC was used the whole time. Temperature ranged between 104 and 95F during the trip.

So if I get 4.7 m/kwh for 53 miles, it means that I used up 11.3 kwh.
If I have 11 miles left on the GOM (I know, not accurate, but it'll have to do), that means another 2.34 kwh in my range.

So my roughly total available range is 11.3+2.34=13.64kwh.

The battery is supposed to hold 24kwh. Assuming that Nissan only allows people to tap 70% of this (I'm just guessing here). And I lost 1 capacity bar which is 15%. So supposedly, my battery should have 24*.7*.85=14.28kwh. That's still more than the 13.64 kwh I calculated above.

So a couple of questions:

1. Is the 70% I assumed above a good guess? If not, what should it be?
2. If I'm close to losing 2 bars, then what is the 2 bar capacity loss?

I'm just trying to compare the 13.64 kwh I calculated to see if it jives at all with the remaining capacity of my battery which had 1 bar loss back in early June. Right now, the 13.64 kwh number seems to fall short of what I should have gotten. So I'd like to know where I went wrong on my calculation? Thanks.

1) no. u are using estimates and guessing to make a guess. each is providing a level of error. sure you "could" say you have lost 30% +/- 20% maybe...

the GOM only takes recent driving to determine your 11 miles. if you drove inefficiently you "could" have averaged 3 miles/k meaning you have 3.75 KW plug the GOM does not estimate to empty. it only estimates to a point where you are strongly recommended to plug in

2)2nd bar loss means you have "about" 79%

 

[Stoaty]

The battery is supposed to hold 24kwh. Assuming that Nissan only allows people to tap 70% of this (I'm just guessing here). And I lost 1 capacity bar which is 15%. So supposedly, my battery should have 24*.7*.85=14.28kwh. That's still more than the 13.64 kwh I calculated above.

So a couple of questions:

1. Is the 70% I assumed above a good guess? If not, what should it be?
2. If I'm close to losing 2 bars, then what is the 2 bar capacity loss?

1. Nissan allows you to use all of the battery except the top 5% and the bottom 2%. Effective available energy that can be drawn from the battery is considered to be around 21 kwh when battery is new (some losses in the conversion).
2. Battery capacity loss at 2 bars is 15 + 6.25 = 21.25%

 

[Volusiano]

The battery is supposed to hold 24kwh. Assuming that Nissan only allows people to tap 70% of this (I'm just guessing here). And I lost 1 capacity bar which is 15%. So supposedly, my battery should have 24*.7*.85=14.28kwh. That's still more than the 13.64 kwh I calculated above.

So a couple of questions:

1. Is the 70% I assumed above a good guess? If not, what should it be?
2. If I'm close to losing 2 bars, then what is the 2 bar capacity loss?

1. Nissan allows you to use all of the battery except the top 5% and the bottom 2%. Effective available energy that can be drawn from the battery is considered to be around 21 kwh when battery is new (some losses in the conversion).
2. Battery capacity loss at 2 bars is 15 + 6.25 = 21.25%

Thanks for this info.

So assuming that I'm very close to 2 capacity bar loss (although I'm still showing 1 bar loss only), 21 kwh * .79 = 16.6 kwh roughly, the remaining capacity I should have.

But my calculation based on the 53 miles at 4.7 m/kwh plus the guess for the 11 miles remaining on the GOM at roughly 4.7 m/kwh is 13.6 kwh. (I'm assuming the 11 GOM is accurate enough based on my recent driving).

16.6 kwh - 13.6 khw = 3 kwh unaccounted for. Usually at around 11 or 12 miles remaining on the GOM, I get the LBW. So it could have gone on any time at that point although it didn't.

So when does VLBW go on? At 0 miles on the GOM? What should the energy remaining be between VLBW to turtle? Could it be 3 kwh which may explained for the 3 kwh unaccounted for in my calculation?

 

[DaveinOlyWA]

The battery is supposed to hold 24kwh. Assuming that Nissan only allows people to tap 70% of this (I'm just guessing here). And I lost 1 capacity bar which is 15%. So supposedly, my battery should have 24*.7*.85=14.28kwh. That's still more than the 13.64 kwh I calculated above.

So a couple of questions:

1. Is the 70% I assumed above a good guess? If not, what should it be?
2. If I'm close to losing 2 bars, then what is the 2 bar capacity loss?

1. Nissan allows you to use all of the battery except the top 5% and the bottom 2%. Effective available energy that can be drawn from the battery is considered to be around 21 kwh when battery is new (some losses in the conversion).
2. Battery capacity loss at 2 bars is 15 + 6.25 = 21.25%

Thanks for this info.

So assuming that I'm very close to 2 capacity bar loss (although I'm still showing 1 bar loss only), 21 kwh * .79 = 16.6 kwh roughly, the remaining capacity I should have.

But my calculation based on the 53 miles at 4.7 m/kwh plus the guess for the 11 miles remaining on the GOM at roughly 4.7 m/kwh is 13.6 kwh. (I'm assuming the 11 GOM is accurate enough based on my recent driving).

16.6 kwh - 13.6 khw = 3 kwh unaccounted for. Usually at around 11 or 12 miles remaining on the GOM, I get the LBW. So it could have gone on any time at that point although it didn't.

So when does VLBW go on? At 0 miles on the GOM? What should the energy remaining be between VLBW to turtle? Could it be 3 kwh which may explained for the 3 kwh unaccounted for in my calculation?

http://www.mynissanleaf.com/blog.php?u=291&b=134" onclick="window.open(this.href);return false;

LB @17.4 & 49 80.8
VLB @ 8.5 & 24 and 92.7
lost first power circle @ 98.8 miles
turtle @ 2.8 and 8 and 99.3

this was winter so temp controlled loss only gave me about 19 KW to use but it reads

Low Battery @ 17.4 % SOC, 49 GID odometer 80.8 so you have 15% between one to the other, but the GOM actually works till VLB where you only have about 5% usable pack left but i drove almost 8 miles at 5.3 miles/K

 

[GerryAZ]

Volusiano,

Since I lost my top capacity bar, the SOC and GOM (DTE, sorry Nissan) instrumentation has been very pessimistic. Also, I am now getting more miles between LBW and VLBW than before. The net effect is that between 1/4 and 1/3 of my useable battery capacity is still available when I get down to 2 bars on the SOC gauge. The estimated time to charge has been affected to the point that it now underestimates charging time. Therefore, I think the errors in the dash instrumentation are leading you to inaccurate capacity loss calculations.

Gerry