Capacity Loss on 2011-2012 LEAFs

[TomT]

I was going to update mine and was greeted with this:

Real World Battery Capacity Loss
for Real World Battery Capacity Loss

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2. Go to The Tracking Wiki...

 

[Stoaty]

Your user name or IP address has been blocked.

The block was made by Wxxyz. The reason given is spammer.

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[LEAFfan]

and it hit 8 TBs during the day (highest TS was 101 with the other two around 99F)

Interesting, I haven't seen 8 TBs till the sensors were reporting 118F.

Yes, that IS interesting because when I was QCing a few weeks ago, I was at 7TBs. I charged for about 30 mins. to 90%. I then had 9 TBs and the highest TS was 112F. So, maybe that tweaking of the pack chemistry really keeps the pack from getting so hot.

 

[RegGuheert]

and it hit 8 TBs during the day (highest TS was 101 with the other two around 99F)

Interesting, I haven't seen 8 TBs till the sensors were reporting 118F.

Yes, that IS interesting because when I was QCing a few weeks ago, I was at 7TBs. I charged for about 30 mins. to 90%. I then had 9 TBs and the highest TS was 112F. So, maybe that tweaking of the pack chemistry really keeps the pack from getting so hot.

According to the 2011 service manual, the range for the eighth temperature bar is 97F to 120F. It also says that the bars may be affected by battery capacity. While that makes little sense to me, perhaps it comes into play here somehow.

 

[surfingslovak]

According to the 2011 service manual, the range for the eighth temperature bar is 97F to 120F. It also says that the bars may be affected by battery capacity. While that makes little sense to me, perhaps it comes into play here somehow.

That was my first thought too. I believe that degradation, and by extension increased internal resistance, are factored into the battery pack temperature gauge.

 

[Randmac]

Lost first capacity bar today. 34,148 miles.

 

[DaveEV]

I've observed that the battery tends to stay about 10 degrees F above ambient even after 'cooling' overnight. It tends to bake.

That's a bit warmer than my pack - park at night with the pack in the upper 70s, garage temps in the low 70s range, pack in the upper 70s range, charge a couple hours back to 80%, pack is in the mid 70s in the morning. Maybe your pack starts out significantly warmer.

That might help keep the battery cooler or it might dump additional heat in the area near the battery making it hotter.

Depends on how hot the pack is and how hot the air getting blown back off the AC condensers is. If your pack is significantly above ambient it might help bring down temps, if it's not, it may warm the pack up a bit more. Either way, I wouldn't expect it to be significant.

 

[Joeviocoe]

I was going to update mine and was greeted with this:

Real World Battery Capacity Loss
for Real World Battery Capacity Loss

You do not have permission to edit this page, for the following reason:

Your user name or IP address has been blocked.

The block was made by Wxxyz. The reason given is spammer.

Start of block: 15:31, 20 February 2011
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Intended blockee: Sheridan449636

You can contact Wxxyz or another administrator to discuss the block. You cannot use the 'e-mail this user' feature unless a valid e-mail address is specified in your account preferences and you have not been blocked from using it. Your current IP address is 24.171.141.161, and the block ID is #1. Please include all above details in any queries you make.

2. Go to The Tracking Wiki...

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[TomT]

Technically it is dynamic but it hasn't actually changed in over 6 years...

Do you have a Static or Dynamic IP Address?

 

[TomT]

Nope.

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[RegGuheert]

That was my first thought too. I believe that degradation, and by extension increased internal resistance, are factored into the battery pack temperature gauge.

But it's a bit of a bizarre concept since the sensors are measuring temperature and the gauge is displaying temperature.

The only way it makes ANY sense is if you assume that they are measuring the temperature of the CASE of the modules, but attempting to display the INTERNAL temperatures with the bars. Since the BMS estimates the electrical resistance of the battery it seems plausible that they would try to do this. That said, it seems the main result is to simple make the gauge confusing, since there is more to temperature effects than just thermal resistance. Thermal capacitance is significant in an EV like the LEAF, so the relationship between these two temperatures is complicated and also depends on other factors including battery current, vehicle wind velocity and ambient temperatures.

Then again, the gauges in the LEAF have never been its strong point...

 

[surfingslovak]

Then again, the gauges in the LEAF have never been its strong point...

Right, precisely. My understanding is that the battery will likely get hotter during operation (and even charging) as its internal resistance increases as part of the natural aging process. Normally, this wold manifest itself by higher temperatures indicated on the gauge, but Nissan has apparently chosen to mask the behavior by shifting the thresholds at which temperature gauge bars are illuminated. It's late and I could be remembering this incorrectly, but that's how I remember my rationalization of this behavior. It's a bit like the capacity gauge, where the bars look the same visually, yet the first bar translates to substantially more capacity loss than the subsequent bars.

As an engineer, I can understand that a UX person might have considered this a good idea, and why they thought that giving the impression of a linear gauge is the right thing to do. But looking at the endless stream of questions this decision has generated, you have to wonder, if this was indeed the right choice. I think I feel similarly about the temperature gauge, and it seems like you are not a fan of the current implementation either?

Personally, I think that the LEAF should just display the battery temperature as a digit, perhaps somewhere close to the display showing the ambient temp. In fact, perhaps that wold be a good suggestion to put on the list of improvements to be considered by the LEAF engineering team.

 

[DaveinOlyWA]

Maintain a low, average state of charge? Check.
Only charge to 80% or less? Check.
Only charge during the morning when it's "cool"? Check.
Park car outside at night to keep "cool"? Check.
Park car near trees so it gets shade in the afternoon? Check.

Lost first capacity bar this morning at only 8,260 miles and 11 months.

Your Leaf is doing even worse than the Battery Aging Model suggests for your area (around 88-89% capacity remaining)... what a bummer!

Sloaty; he may not be doing worse. it could be the capacity bars disappearing early. noticing a small trend where cooler climates (Like Steve Marsh's bar disappearing at greater than 17.5% loss) bars stay longer and warmer climates, bars leave sooner. the fact that Weatherman's bar disappears as the heat of Summer is starting to crank up does not surprise me. We need to get a meter on his car ASAP to verify his capacity is as low as it "seems" to be.

another thing is the statement of his 80% charging all the time

 

[mwalsh]

Mine is about same age and I can still can do 72 miles in mixed cycle on mostly flat terrain just after hitting LBW. Never needed to go farther on a single charge but I'm guessing 80 is not out of the question. 100 mile claim was a stretch, but doable still.

Bringing this discussion over here, even though I'm technically cross posting, because it didn't get any traction in the Battery Warranty thread. Hope nobody minds.

Here is something that is bothering me - I am down to ~220 Gids on a charge. With the accepted threshold for bar loss being ~232 Gids, technically I should have lost a bar some time ago. Yet I still have all twelve. What is up with that?

Another thing that bothers me is the similarity between my car and xtremeflyer's - our cars are more or less the same age (mine was delivered 5 months earlier); we're at the same mileage; we live in similar micro-climates (Garden Grove vs. Orange, unless he lives up in the hills?); and it looks like our commutes are similar and our cars sit in similar micro-climates while we work (I work in Hawthorne and I assume, if he's doing 10 miles more than me daily, he's up around there too?). So, theoretically speaking, our battery packs should be twins. Yet he's lost two bars already? It just doesn't make sense. Actually, I'd like to discuss any unknown differences between him and me. The only one that seems like it could possibly make a difference to the pack is parking - I let my car sit out at night, and I'm wondering if his might be garaged? Xtremeflyer?

 

[JPWhite]

another thing is the statement of his 80% charging all the time

What's the implication you are driving at?

 

[DaveinOlyWA]

Mine is about same age and I can still can do 72 miles in mixed cycle on mostly flat terrain just after hitting LBW. Never needed to go farther on a single charge but I'm guessing 80 is not out of the question. 100 mile claim was a stretch, but doable still.

Bringing this discussion over here, even though I'm technically cross posting, because it didn't get any traction in the Battery Warranty thread. Hope nobody minds.

Here is something that is bothering me - I am down to ~220 Gids on a charge. With the accepted threshold for bar loss being ~232 Gids, technically I should have lost a bar some time ago. Yet I still have all twelve. What is up with that?

Another thing that bothers me is the similarity between my car and xtremeflyer's - our cars are more or less the same age (mine was delivered 5 months earlier); we're at the same mileage; we live in similar micro-climates (Garden Grove vs. Orange, unless he lives up in the hills?); and it looks like our commutes are similar and our cars sit in similar micro-climates while we work (I work in Hawthorne and I assume, if he's doing 10 miles more than me daily, he's up around there too?). So, theoretically speaking, our battery packs should be twins. Yet he's lost two bars already? It just doesn't make sense. Actually, I'd like to discuss any unknown differences between him and me. The only one that seems like it could possibly make a difference to the pack is parking - I let my car sit out at night, and I'm wondering if his might be garaged? Xtremeflyer?

Michael *that* is probably the reason for the LEAF software update. its to get all the LEAFs "on the same page in a manner of speaking. Steve actually tested in a range from 228-232 so his SOC could have been as low as 81% and his bar did not disappear until a few weeks after the test so the bar could have disappeared below 20%.

what is really needed is to get a meter on these cars ASAP when the bars go or hope that this software fix standardizes the bars for all LEAFs in all climates

 

[RegGuheert]

Michael *that* is probably the reason for the LEAF software update. its to get all the LEAFs "on the same page in a manner of speaking. Steve actually tested in a range from 228-232 so his SOC could have been as low as 81% and his bar did not disappear until a few weeks after the test so the bar could have disappeared below 20%.

So the obvious questions I have are:

1) Was the original service manual correct in stating that the first bar would be lost at 85% battery capacity?
2) If the answer to 1) is "Yes", then will the software update possibly result in a spate of bars disappearing that weren't previously gone in spite of Andy Palmer's statements to the effect that the capacity meter tended to overpredicting loss. (Yes, I understand that reducing an overprediction means there will be less loss indicated, but if the thresholds also need to be corrected, then that goes in the opposite direction.)

So who wants to go first with the software update?

Perhaps edatoakrun should do it since he is the most convinced that his capacity loss is very low. Ed?

 

[mwalsh]

So who wants to go first with the software update?

Perhaps edatoakrun should do it since he is the most convinced that his capacity loss is very low. Ed?

NOT ME! As you'll recall, I've already had issues when it comes to LEAF software updates! :?

 

[RegGuheert]

NOT ME! As you'll recall, I've already had issues when it comes to LEAF software updates! :?

Me, too! Our LEAF was out of commission for the weekend after the braking update.

 

[LEAFer]

It was cool overnight ... the LEAF showed 5 TBs and an OAT of 61F. (We know it's slow to update). Around 09:10 I sat in the car to take some more data with Turbo3's LBM (LEAF Battery Monitor). Couldn't get the BT to connect. Turned the car on/off a few times. It had been charged on EndTimer overnight to 80% by 08:00.

On second power-up ... lost our first capacity bar !

Bummer on losing that bar. I see that your SOC is 75%. Had you driven at all since it finished charging earlier?

On second power-up ... lost our first capacity bar !

It appears that around 83% CAP on the Leaf Battery App is where you are likely to lose the first capacity bar. Have noted this for a couple of other reports.

Seems too coincidental, but that comes out to 55 Ah with the default "100%" rating of 66.2566 Ah.
Edit: Yeah, it is. I see that LEAFer is showing 55.23 Ah when he lost the bar. Maybe the threshold is 55.25 Ah? Davewill's car was also showing just below 55.25 Ah (55.18) when he noticed he lost his bar.

Regarding the 75% after a (supposedly) 80% charge: I don't know what the SOC was when I first turned on the car, since I had a lot of trouble getting the BT connected; sitting for about 15 minutes, may have had some A/C on for a short while, plus radio, and probably headlights. But I just checked it: SOC 79.9%, 6TBs, Temps: 86.2, 84.9, 83.4, 82.9 (yesterday was 104F, cooled overnight to only around 70F, already 75-80F now), 198 'Gids, 15.8kWh, 10.5V, 15-16mV spread, 55.11Ahr=83.18%.

I have not made any adjustments in the LBM Settings Screen.

Actually, my Ahr was 55.26 after the bar loss. (not 55.23 ... minor, but still a difference)