Capacity Loss on 2011-2012 LEAFs

Multiply the percentage number by 2.81 for Gids.

opossum said:

Sorry, KJD, but I don't recall what the ScanGauge math is, but I'm sure someone else can translate those percentages into GIDs.

Click to expand...

Hi Everyone,

Here are some measurements:

Phx 100% 229 Gids 6/18/2012
Phx 100% 222 Gids 7/1/2012

I will try to make measurements twice a month

opossum said:

Hey everyone.

I (we) wanted to clear up a few vague items in the “who has lost a bar” list and give everyone a bit of recent Phoenix capacity loss information...

“Azdre” (the originator of this massive thread) and I own the same Phoenix Leaf, VIN #0500. We lost our second bar several weeks ago and appear to be on the cusp of losing the third. So on the current list, our car is one of the two I had reported earlier had lost two bars in Phoenix (notes section).

Sorry for being so vague earlier. Things were happening quickly. Knowing that Nissan monitors this forum, we were walking a fine line between declaring too much on a public forum and still sharing our experience with everyone. We are very concerned about this dramatic and non-linear (non-gradual!) capacity loss, and wanted to be sure our bargaining position with Nissan was not compromised by anything we said on this forum.

Many days have since passed, the trend is quite clear, and it is fairly obvious to everyone now (hopefully) that this capacity loss is not due to poor owner treatment...

Click to expand...

Thanks for the update and additional info.

I think it's pretty clear, by analyzing the reports by geography and climate, that the primary determinant of battery bar loss is the battery pack's long term exposure to high ambient temperatures.

What is not clear to me, is whether bar loss is entirely the result of lost battery capacity, or reflects, at least in part, the LEAFs BMS operation.

As I understand it, your ScanGauge reports are calculated from the same data widely reported by those with gid monitors. This reports the amount of energy the battery pack accepts at a given charge setting, which is not necessarily a fixed percentage of total battery capacity. It may, instead, reflect, in part, the LEAFs BMS operation.

The fact that many have reported rapidly dropping gid counts and Scangauge reports over the last few months, as temperatures have risen, seem to me, to indicate that either Nissan has equipped LEAFs with batteries with extremely poor resistance to hot temperatures, or that there is another factor at work.

It seems to be generally accepted, that the best way to reduce battery capacity in high heat conditions, is to limit the charge level.

IMO, it would have been extremely shortsighted (if not a total BEV plan FUBAR) for Nissan not to have equipped the LEAF with a BMS that would adapt to climate conditions, to allow higher charge levels where they are most needed, in cold climates, and reducing maximum charge level, under hotter conditions, to prolong battery life. In fact, there may be quite a bit of anecdotal evidence tending to indicate BMS effects on gid counts, limiting charge levels in hotter climate conditions, reported on various threads.

This is not to say we should not be very concerned about you bar losses. You, even more than the rest of LEAF owners, have a right to be angry with Nissan's virtual embargo of battery capacity information, ever since the LEAF was launched. And it does not indicate the bar loss LEAFs have not lost very significant (and maybe still totally unacceptable) capacity permanently. Every LEAF will lose some battery capacity every day. Hot climate LEAFs will lose capacity faster than Cold climate LEAFs, independent of other battery use variables.

But I would encourage all to consider the methodical collection of actual long-term battery performance data, as opposed to assembling the fragmentary evidence that Nissan has provided, from the dash bars, and in statements on what they indicate, with relatively limited observations of actual battery performance, and forming conclusions, uncritically.

I'm curious about something. Has anyone with a lost battery bar actually tried running the leaf down until it quits driving, then charging it back up?

I ask because I know with the Apple laptop computers I refurbish, many cases the battery computer (yes, there is a little computer inside the battery pack) will report that a certain number of mA-hours but can be wrong. So the computer will estimate a total of 1 hour of run-time, for example. but if I let the computer run with sleep-mode disabled for an hour it will reach the point of saying there are zero minutes remaining and warning the user to save their work, etc. But I just let it go and sometimes it will run another hour or two like that. After it finally shuts off, I'll recharge it and reboot it. Then it will suddenly say the battery has more mA hours than it had before as well as the estimated run-time might now show 2 or 3 hours. Essentially what I'm doing is re-calibrating the battery computer.

Presumably this happens because the previous owner of the computer always shut it off when the battery warning came up rather than allowing it to run to the point the voltage dropped so low it had to shut down. Since the capacity is partly measured based on previous history, sometimes you have to show the computer that there really is more capacity than it thinks.

I've no idea if the Leaf works this way. But it might be worth a try.

edatoakrun said:

What is not clear to me, is whether bar loss is entirely the result of lost battery capacity, or reflects, at least in part, the LEAFs BMS operation.

Click to expand...

Here's the thing: If it was truly a temperature-related BMS "protection" feature, wouldn't we have seen losses in range and capacity bars last summer? Most of us in Phoenix had these cars for the FULL 2011 summer. And as others have mentioned, it was exceptionally warm last year. Phoenix is warm every summer. Last year broke several records. Yet our range was awesome all summer long. This year, we've just barely crept into summer and yet people are dropping capacity bars and significant real world range like we now have a bank of capacitors in the car instead of batteries. We've even seen a few cars out here with the old firmware drop bars and range, so we can't even blame all or any of this on a software update cutting out usable capacity at high temperatures.

I added a summary of these 100 pages to the original post.

opossum said:

edatoakrun said:

What is not clear to me, is whether bar loss is entirely the result of lost battery capacity, or reflects, at least in part, the LEAFs BMS operation.

Click to expand...

Here's the thing: If it was truly a temperature-related BMS "protection" feature, wouldn't we have seen losses in range and capacity bars last summer? Most of us in Phoenix had these cars for the FULL 2011 summer. And as others have mentioned, it was exceptionally warm last year. Phoenix is warm every summer. Last year broke several records. Yet our range was awesome all summer long. This year, we've just barely crept into summer and yet people are dropping capacity bars and significant real world range like we now have a bank of capacitors in the car instead of batteries. We've even seen a few cars out here with the old firmware drop bars and range, so we can't even blame all or any of this on a software update cutting out usable capacity at high temperatures.

Click to expand...

Actually, as I posted several days ago on this thread, It looks like it has been considerably hotter in Phoenix over the last few months, than either last year, or the long term average. As far at the BMS is concerned, an about three degree F average temperature increase, from already very high ambient levels, could be all that is required to trigger further BMS charge level restrictions.

Fairly significant increase in reported Phoenix temperatures April through June 2012, as opposed to the 30 year average, as well as to last year.

That can't be helping...

You can use the link below to find average, as well as daily high, low, etc., for your own location.


Quote:

Phoenix Area (ThreadEx Station)
Monthly Totals/Averages
Average Temperature (degrees F)
Years: 1981-2010

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual
Average 56.5 59.8 65.3 72.8 82.1 90.9 94.8 93.6 88.4 76.7 64.2 55.5 75.0


Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual
2011 55.7 55.2 67.8 74.3 78.8 90.8 95.2 98.3 91.4 78.8 63.5 53.2 75.2

Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual
2012 58.7 60.3 65.9 75.1 84.5 93.8 -
http://www.nws.noaa.gov/climate/xmacis.php?wfo=psr" onclick="window.open(this.href);return false;

Click to expand...

And again, if there is a BMS charging restriction, the bar display and did/SOC results would presumably display results reflecting both its effects, as well as battery degradation. If both of these did not result in a total "15%" capacity reduction last Summer, no dash bar would have been lost. The only comprehensive record of gid counts from last Summer in Phoenix, from TickTock (IIRC) may, IMO, show BMS operation, but not quite the "15%" total charge level reduction, leading to one bar loss.

shrink said:

Nissan's inaction and insistence on calling this "normal" is maddening. Owners appear to be seeing the expected 5-year capacity in a little over a year and there doesn't seem to be a good sense of when this loss will slow or flatten out.

Click to expand...

It is frustrating. To restate the obvious, Nissan have not taken a pro active approach to this problem, unlike what GM did with the Volt Fires, offering to buy back cars etc etc etc. No big media blitz means Nissan have time to decide what to do.

So if we once again accept the obvious, they are taking a wait and see approach, then what are they waiting for? Capturing lots of data is clear so they can figure out what's happening and what to do about it. If 70% of original capacity is considered end of life for traction batteries and Nissan also consider 70% to be end of life, which they predict on average will be at year 10, they may wait until a good number of end-of-life situations arise before taking any action at all.

I hope they are busy engineering a hot climate option for the LEAF and will offer favorable trade-ins or buy-backs for customers who's cars reach 'end-of-life' in the first few years of ownership.

I suppose what I'm saying in a round about way, is that I hope Nissan are internally accepting of and are active with the problem and something good will come out of it. It's hard to be patient when there is silence or just a repeat of the battery life expectations/projections.

Your own data show just how hot it was last year. Okay, comparing month to month, a few of these early months may have been warmer than last year. But look at how we finished the game last year. The two hottest months last year were far hotter than *anything* we have seen yet this year! We roasted our *&^%$# off for over 4 months, whereas this year, while the late winter and spring truly were warm, we have just barely crept into the beginning of the 4 months of average 90 degree temperatures.

2011: 90.8 95.2 98.3 91.4
2012: 93.8 TBD TBD TBD

Come fry eggs out here on the sidewalk for a FULL summer and you'll see what's going on. :lol:

Updating about Azdre and Opossum being owners of the same car and their reported 2nd bar capacity loss.

1. Azdre & Opossum - April 26, 2012. 16.6K miles/13 months ownership. Phoenix (2nd bar loss reported 6/14/2012 @~19K miles)
2. bturner - May 12, 2012. 13.6K/12 months. Phoenix
3. turbo2ltr - May 18, 2012. 13K/15 months. Phoenix (2nd bar loss reported 6/29/2012)
4. TickTock - May 20, 2012. 14K/12 months Phoenix
5. Volusiano - May 20, 2012. 16.5K/12 months. Phoenix
6. Mark13 - May 22, 2012. 15.7K/12 months. Phoenix (2nd bar loss reported 7/1/2012)
7. Leafkabob - May 26, 2012. 9.5K/12 months. Phoenix
8. Cyellen - June 7, 2012. 10.2K/ 14 months. Phoenix
9. RickS - June 10, 2012. 11.3K/13 months. Phoenix
10. Pipcecil - June 17, 2012. 20.2K/12 months. Dallas, Texas
11. Phxsmiley - June 17, 2012. 13.7K/10 months. Phoenix
12. AZknauer - June 17, 2012. 9.2K/13.5 months. Phoenix
13. Myleaf - June 19, 2012. 13.3K/14 months. Phoenix
14. johndoe74 - June 5, 2012. 13.5K/ 9 months. Phoenix
15. Matt Ferris - June 20, 2012. 15K/ 12 months. Dallas, Texas
16. Shrink - June 21, 2012. 10.2K/ 10.5 months. Phoenix (sold that Leaf, replaced w/leased '12 Leaf)
17. ravi100 - June 24, 2012. 13.1K/ 13.5 months. Southlake, Texas (no longer has Leaf)
18. ev4me - approx. June 1, 2012. 7K/ 15 mos. Phoenix (Dropped 2 bars)
19. jspearman - June 28, 2012, ?/10.5 months. Phoenix

Not reported by owner, but by others:
1. Opossum has reported of two cars in Phoenix that have lost 2 bars.
2. Leafkabob reported a street encounter with a Leaf owner who stated he lost a bar after about a year.
3. Skywagon approx. May, 2012. Phoenix (supposedly no longer has Leaf)

opossum said:

edatoakrun said:

What is not clear to me, is whether bar loss is entirely the result of lost battery capacity, or reflects, at least in part, the LEAFs BMS operation.

Click to expand...

Here's the thing: If it was truly a temperature-related BMS "protection" feature, wouldn't we have seen losses in range and capacity bars last summer? Most of us in Phoenix had these cars for the FULL 2011 summer. And as others have mentioned, it was exceptionally warm last year. Phoenix is warm every summer. Last year broke several records. Yet our range was awesome all summer long. This year, we've just barely crept into summer and yet people are dropping capacity bars and significant real world range like we now have a bank of capacitors in the car instead of batteries. We've even seen a few cars out here with the old firmware drop bars and range, so we can't even blame all or any of this on a software update cutting out usable capacity at high temperatures.

Click to expand...

Here's a thought. What if the Nissan software (or firmware) updates that most of us have had done between last summer and this summer modified the behavior of the BMS so that this summer, the BMS more actively inhibits charging to protect the pack in high temps? Have all of the folks who have reported bar loss had the software updates?

EDIT: I realize that if this was the case, it would have been easy for Nissan's spokespeople to say that right away, since it would be a positive statement about the car's safeguards to protect the batteries. Anyway, just a thought.

edatoakrun said:

As I understand it, your ScanGauge reports are calculated from the same data widely reported by those with gid monitors. This reports the amount of energy the battery pack accepts at a given charge setting, which is not necessarily a fixed percentage of total battery capacity. It may, instead, reflect, in part, the LEAFs BMS operation.

Click to expand...

If this were the case, along with low GID numbers, you'd also see low voltage numbers. So far, I haven't see any evidence that shows that voltage is dropping with GID numbers which would indicate that the BMS is limiting charge level in response to temperatures. turbo2ltr posted the other day that he got 393.7V on a 100% charge.

opossum's range test a few weeks ago (100%-LBW, 58.6mi, 5mi/kWh) clearly shows a significant reduction in capacity - I estimate about 14 kWh usable. In other words, they've lost about 30% of their usable capacity in ~20k miles and <16 months. But I'd bet that no-one in AZ expected to reach that level of range reduction until 5 years had passed.

What is maddening to me, even though I live in a cool climate, is that my investment in the car is at risk due to Nissan's inexplicable response. I know I'm not the only one starting to get cold feet as a result of other's cold feet. Nissan needs to assure all of us that our value will be protected. The fear contagion is definitely spreading and is very self fulfilling, sales will surely suffer at least some, pretty much everywhere and resale values are/will be declining. If Nissan isn't careful, they are going to see a "cut and run" cascade. they've enjoyed a corner on a market of people that are articulate, outspoken and strategic, a group that if slighted, will be unforgiving in their exit of said market.

Nissan needs to pony up and openly define "gradual". I predict that by the end of this summer we will be seeing some with 3 and 4 bars lost, those of us even in cool climates need proactive assurance that such a loss is not considered "gradual", "normal" or "expected" or any other head in the sand BS and will be handled under warranty.

JPWhite said:

shrink said:

Nissan's inaction and insistence on calling this "normal" is maddening. Owners appear to be seeing the expected 5-year capacity in a little over a year and there doesn't seem to be a good sense of when this loss will slow or flatten out.

Click to expand...

It is frustrating. To restate the obvious, Nissan have not taken a pro active approach to this problem, unlike what GM did with the Volt Fires, offering to buy back cars etc etc etc. No big media blitz means Nissan have time to decide what to do.

So if we once again accept the obvious, they are taking a wait and see approach, then what are they waiting for? Capturing lots of data is clear so they can figure out what's happening and what to do about it. If 70% of original capacity is considered end of life for traction batteries and Nissan also consider 70% to be end of life, which they predict on average will be at year 10, they may wait until a good number of end-of-life situations arise before taking any action at all.

I hope they are busy engineering a hot climate option for the LEAF and will offer favorable trade-ins or buy-backs for customers who's cars reach 'end-of-life' in the first few years of ownership.

I suppose what I'm saying in a round about way, is that I hope Nissan are internally accepting of and are active with the problem and something good will come out of it. It's hard to be patient when there is silence or just a repeat of the battery life expectations/projections.

Click to expand...

I expect Nissan to continue doing nothing until the battery is basically unusable in the vehicle. Only then possibly give a prorated adjustment on something newer. I thought there was a performance warranty. No cars have hit that threshhold yet. AZ might well test it soon.

I just wish Nissan would commit to a replacement price for the entire battery.

Boomer23 said:

Here's a thought. What if the Nissan software (or firmware) updates that most of us have had done between last summer and this summer modified the behavior of the BMS so that this summer, the BMS more actively inhibits charging to protect the pack in high temps? Have all of the folks who have reported bar loss had the software updates?

Click to expand...

The BMS could be (part of) the issue, but not all of it. The message of mine that you quoted answers your own question.

smkettner said:

I expect Nissan to continue doing nothing until the battery is basically unusable in the vehicle. Only then possibly give a prorated adjustment on something newer.

Click to expand...

Perhaps you guys will get a new pack once it hits 3 bars lost, with forced air AC cooling, similar to what Coda and Honda are doing.

The fact that many have reported rapidly dropping gid counts and Scangauge reports over the last few months, as temperatures have risen, seem to me, to indicate that either Nissan has equipped LEAFs with batteries with extremely poor resistance to hot temperatures, or that there is another factor at work.

Click to expand...

I think you're barking up the wrong tree here.
I'm guessing you aren't familiar with typical charge profiles.

Temperature compensation during a charge profile is typically manifested as a voltage compensation. A typical charge profile will charge constant current until the batteries reach voltage X, then switch to a constant voltage until the current drops to Y amps. They typically will then switch to a low constant current until voltage Z is reached. When there is a temperature compensation, that will cause the BMS to adjust voltage X and Z. I don't know about other people, but I know I saw the full pack voltage after 100% charge yet I have two bars missing. So with that, my speculation is that it has nothing (or very little) to do with the BMS, and mostly to do with the batteries degrading in the heat.

smkettner said:

I thought there was a performance warranty. No cars have hit that threshhold yet. AZ might well test it soon.

Click to expand...

I think Mark Perry said that the only thing the Leaf battery is warrantied against is a performance loss. But he clarified that this performance loss is not the same as range/capacity loss. He said the performance loss is when the battery doesn't output sufficient voltage to propel the car properly. He said this is mostly due to cell malfunction and it would be easy to swap out the bad cell(s) with good one(s) to correct the performance loss. But this doesn't help correct the capacity loss situation.

If the two are not related, extreme capacity loss may still not cause any performance loss.

The way Nissan is handling this, and the entirely foreseeable consequences to their rep, put me in mind of the following:

Mother to Child: "Nissan, don't you take that gun out of the case." (Nissan ignores her)

MtC: "Nissan, don't you put bullets in that gun!" (Nissan ignores her)

MtC: "Nissan, don't you play with that gun!!" (ditto)

MtC: "Nissan, don't you put your finger on the trigger!!!" (double ditto)

MtC: "Nissan, be careful where you point that gun!!!!" (ditto ad nauseum)

Bang!

ER Doctor to Child: "So, Nissan, tell me how you came to shoot yourself so badly in the foot?"

Nissan: "It was an accident! No one could have expected it to happen!"

even without replacing the battery, it costs about 4k to take the battery out and reinstall it.
I had it done at the local Nissan dealer in connection with an accident and repair.

I was given that figure as the estimate for that work. I will have the bill in about a week.
It seems pretty high to me.