Capacity Loss on 2011-2012 LEAFs

[edatoakrun]

="TonyWilliams"]...I will offer that the data, at a casual glance, suggests that the Gid measurements are flawed between cars.

Does "a casual glance" also show the dash/nav screen calculated and CW reported and calculated kwh use are also "flawed between cars"?

If so, you may also find a significant correlation between these errors and the gid Wh content error you have mentioned, and (perhaps) all will correlate to inaccurate capacity bar loss displays.

However, if you did not monitor the recharge kWh accepted by these LEAFs after the test, you will have missed out on another method (possibly more accurate than a range test) to calculate the actual variable kWh use between cars in this test.

edatoakrun

The ~ 9% (erroneous, I believe) increase in reported charge efficiency is fairly close to the ~11% (also erroneous, I believe) decrease in reported kWh use over my ~one-year-apart-near-identical-driving-condition range test a few weeks ago (from page two of this thread):

"The results from 8/30/12 were:

97.3 miles to VLB, 98.9 miles in total, by the odometer.

CW: 96.5 (~2.5% under-report) total miles, at 5.7 m/kWh, 16.8 kWh used from 100% to about the same capacity level, slightly past VLBW.

Compare this test with my first test on 9/7/11:

91.5 miles to VLB, 93.4 in total, by the odometer

CW: 91.1 (~2.5% under-report) total miles, at 4.9 m/kWh, 18.7 kWh used from 100% to about the same capacity level, slightly past VLBW."


It seems very likely to me that both are reflecting the same underlying error in my LEAF’s dash, nav screen and CW kWh use reports, as also effected by other variables which I cannot eliminate from my observations.

So, I believe that the recharge time results are compatible with my range tests, which indicate no observed reduction in range, both probably indicating that my LEAF has no observable loss of available battery capacity (though some amount has almost certainly occurred) over the last 12 months.

I think it is also very likely that many other LEAFs have similar errors in kWh reports, quite possibly due to the gid Wh variability TickTock observed last year, and that capacity bar displays might be similarly effected. Not having lost a bar (yet) or ever having monitored my gid count, I can’t observe those results.

I do think that anyone seeing capacity bar losses or dropping gid counts should try both range and charge capacity tests, to try to more accurately determine their LEAF’s actual loss of battery capacity.

http://www.mynissanleaf.com/viewtopic.php?f=31&t=9064&start=30" onclick="window.open(this.href);return false;

 

[DaveinOlyWA]

ya, its becoming clearer that the GOM is just the tip of the iceberg as far as misleading data the LEAF provides. nothing other than the speedometer and odometer on the LEAF can be believed here.


when Perry said it was a gauge error, i did not think he was referring to the entire car.

 

[TickTock]

I have enough data that a believable trendline is forming (no easy way to plot in google - switch to the compute tab to see/check the linear fit calculations). It looks like on 10/8/2012, I will be at 19.67 capacity which is 7.6% lower then I had on 10/8/2011. This is filtering all the noise and plotting a best-fit linear trendline on the data. I cannot say with surety how much I had lost by 10/8/2011 (it was 4 months old by then) but based on Collected Data, I was down 18% from the numbers reported by new Leaf owners. Note that none of this is dependent on gid accuaracy - just data measured from the wall (the gid-based data is showing a lot of seasonal fluctuations).

I am a bit skeptical (or maybe just jealous...) of those "normalized" results of up to 27kWh capacity.

I'm with you there - just not enough datapoints nor control to draw conclusions. If we believe the 87% loss that Nissan said I had on 8/7/2012, then a un-degraded Leaf should only pull 22.9kWh for a dead to 100 charge. At 91% efficiency this would imply Nissan is not using 13% of the stated 24kWh capacity.

 

[edatoakrun]

I have enough data that a believable trendline is forming (no easy way to plot in google - switch to the compute tab to see/check the linear fit calculations). It looks like on 10/8/2012, I will be at 19.67 capacity which is 7.6% lower then I had on 10/8/2011. This is filtering all the noise and plotting a best-fit linear trendline on the data. I cannot say with surety how much I had lost by 10/8/2011 (it was 4 months old by then) but based on Collected Data, I was down 18% from the numbers reported by new Leaf owners. Note that none of this is dependent on gid accuaracy - just data measured from the wall (the gid-based data is showing a lot of seasonal fluctuations).

I am a bit skeptical (or maybe just jealous...) of those "normalized" results of up to 27kWh capacity.

I'm with you there - just not enough datapoints nor control to draw conclusions. If we believe the 87% loss that Nissan said I had on 8/7/2012, then a un-degraded Leaf should only pull 22.9kWh for a dead to 100 charge. At 91% efficiency this would imply Nissan is not using 13% of the stated 24kWh capacity.

Please remind me, how did you arrive at 91% for 240V 16A efficiency?

Is this to only "80%" or "100%" charge, and shouldn't efficiency also vary with battery temperature?

 

[TickTock]

Please remind me, how did you arrive at 91% for 240V 16A efficiency?

Is this to only "80%" or "100%" charge, and shouldn't efficiency also vary with battery temperature?

http://www.mynissanleaf.com/viewtopic.php?f=31&t=8583&hilit=charging+efficiency

dead to 100% charge.

There may be some fluctuation in efficiency with temperature. Not aware of any studies on this, though.

 

[edatoakrun]

Please remind me, how did you arrive at 91% for 240V 16A efficiency?

Is this to only "80%" or "100%" charge, and shouldn't efficiency also vary with battery temperature?

http://www.mynissanleaf.com/viewtopic.php?f=31&t=8583&hilit=charging+efficiency

dead to 100% charge.

There may be some fluctuation in efficiency with temperature. Not aware of any studies on this, though.

It looks to me like Phil may have been reporting an efficiency rate at a specific temp and SOC, not for over the entire charge range:

...All these measurements were with the Leaf pack at around 62 degrees F and ~65% SoC...

IIRC, many others, using various methodologies, have reported lower efficiencies for the entire charge up to "80%", and even lower efficiencies from "80%" to "100%", when the draw "from the wall" is reduced, but the "overhead" of the charge process remains constant.

I have no very useful observations myself. I'd just like to get the issue cleared up, so that I can use a "standard" efficiency to more closely estimate the kWh "from the wall" of my timed charges to "80%", or "100%".

 

[surfingslovak]

If we believe the 87% loss that Nissan said I had on 8/7/2012, then a un-degraded Leaf should only pull 22.9kWh for a dead to 100 charge. At 91% efficiency this would imply Nissan is not using 13% of the stated 24kWh capacity.

TickTock, pardon my ignorance, but why would we assume 22.9 kW to be reference amount of energy from the wall needed to recharge a Leaf from dead to turtle? I believe the EPA test yielded 24.54 kWh, that's at least what the official numbers imply. Didn't we have a separate thread on this?

 

[GeekEV]

the lack of information concerning this phenomena is confusing to me. Nissan must have known that techies, scientists, engineers and DIY'ers would be their primary first user market. to hide something that is so easy to reverse engineer on our own and then continue to cover up after being exposed is weird.

i wish i could say i know what Nissan plans to do. i can only guess the solution will be good enough for us to forget all the stress, hand wringing and bad thoughts that have built up over the past 3 months.

it is well known that we as Humans are reward-oriented and a good enough reward will do exactly that. but during this "black out" period of inaction, Nissan is losing customers. so i am guessing this solution is good enough to bring them back plus a flood of new ones.

the wait is killing me.

+1,000,000
Particularly on that first paragraph...

 

[JRP3]

This morning i re-lost my #12 capacity bar. I had charged to 80% overnight and had all 12 at the end of that charge when I hit the timer override to get a full charge so the bar was lost during the 80-100 charge.

Are you going to report it to Nissan? Interested to hear what they say about the loss so soon after the reset.

 

[TickTock]

If we believe the 87% loss that Nissan said I had on 8/7/2012, then a un-degraded Leaf should only pull 22.9kWh for a dead to 100 charge. At 91% efficiency this would imply Nissan is not using 13% of the stated 24kWh capacity.

TickTock, pardon my ignorance, but why would we assume 22.9 kW to be reference amount of energy from the wall needed to recharge a Leaf from dead to turtle? I believe the EPA test yielded 24.54 kWh, that's at least what the official numbers imply. Didn't we have a separate thread on this?

Hah! I suppose I should support my statements better and not expect you to read my mind. I get 22.9 by dividing 19.95 by .87. How did I get 19.95 you ask? That is the dead to 100% from-the-wall charge for 8/7/2012 interpolated from the best-fit linear model in my spreadsheet. Check out cell J43 on the compute tab of my spreadsheet. I am being perhaps a tad facetious - I don't really think the battery is 20.8kWh (22.9*91% efficiency). Just pointing out a gap in the understanding. Pretty hard to fully charge a 24kWh battery with only 22.9kWh from the wall - I can state with certainty that our charging efficiency isn't 105% (that's what it would take to make all this add up).

 

[SierraQ]

However, if you did not monitor the recharge kWh accepted by these LEAFs after the test, you will have missed out on another method (possibly more accurate than a range test) to calculate the actual variable kWh use between cars in this test.

We are not interested in how much power each car may or may not be sucking out of the wall to refill itself. (And it is difficult to accurately measure in any case.) Unless you are implying that some Leafs use energy more efficiently than others, miles is directly related to energy, within this test, and I would argue that measuring miles is more consistent, accurate, and far easier than accounting for all energy losses that occur at different rates depending on the charger, battery age, capacity, BMS adjustments, etc. That and the purpose of the test was to evaluate the only thing we really care about which by coincidence is the only thing we can accurately measure--how far the car can go. In the end that is all that matters to the consumer in evaluating the usefulness of the product.

 

[edatoakrun]

However, if you did not monitor the recharge kWh accepted by these LEAFs after the test, you will have missed out on another method (possibly more accurate than a range test) to calculate the actual variable kWh use between cars in this test.

We are not interested in how much power each car may or may not be sucking out of the wall to refill itself. (And it is difficult to accurately measure in any case.) Unless you are implying that some Leafs use energy more efficiently than others, miles is directly related to energy, within this test, and I would argue that measuring miles is more consistent, accurate, and far easier than accounting for all energy losses that occur at different rates depending on the charger, battery age, capacity, BMS adjustments, etc. That and the purpose of the test was to evaluate the only thing we really care about which by coincidence is the only thing we can accurately measure--how far the car can go. In the end that is all that matters to the consumer in evaluating the usefulness of the product.

I am not implying that. I think I can state with certainty that no two cars will ever have exactly the the same battery-to-wheels efficiency.

Neither will any two drivers, drive with identical efficiency. Nor will the same driver, over any two trips.

Neither will road, wind and temperature conditions ever be identical, for any two drives.

I don't know if these inevitable inaccuracies in range tests will prove to be greater than those involved in calculating capacity from the recharges, or not.

I can tell you, I now wish I had kept better track of my recharge capacity over my last year's worth of "100%" to VLBW range tests.

 

[TickTock]

I can tell you, I now wish I had kept better track of my recharge capacity over my last year's worth of "100%" to VLBW range tests.

+1!
It's unfortunate that so few new Leaf owners do this. We have very little information on new Leaf characteristics because most don't come to the forum until after they see the issue and by then it's too late to set the baseline. Certainly was the case for me.

 

[walterbays]

I can tell you, I now wish I had kept better track of my recharge capacity over my last year's worth of "100%" to VLBW range tests.

+1!
It's unfortunate that so few new Leaf owners do this. We have very little information on new Leaf characteristics because most don't come to the forum until after they see the issue and by then it's too late to set the baseline. Certainly was the case for me.

I don't know. When I first got the car I obsessively tracked mileage and Blink and Carwings kWh reports. But I've only once driven down to VLBW, so I'm not sure whether any of my old data would be helpful for anything. After a while I figured out that for all the driving I do the car costs less to operate than I'd spend on soft drinks or snacks, and I lost my motivation for record keeping. So when Blink redesigned their web site making it no longer possible to extract historical data for off-line analysis, I stopped tracking.

It's possible there are more people who started off tracking where the pennies go, and kept it up until they noticed it was only pennies.

 

[TickTock]

I can tell you, I now wish I had kept better track of my recharge capacity over my last year's worth of "100%" to VLBW range tests.

+1!
It's unfortunate that so few new Leaf owners do this. We have very little information on new Leaf characteristics because most don't come to the forum until after they see the issue and by then it's too late to set the baseline. Certainly was the case for me.

I don't know. When I first got the car I obsessively tracked mileage and Blink and Carwings kWh reports. But I've only once driven down to VLBW, so I'm not sure whether any of my old data would be helpful for anything. After a while I figured out that for all the driving I do the car costs less to operate than I'd spend on soft drinks or snacks, and I lost my motivation for record keeping. So when Blink redesigned their web site making it no longer possible to extract historical data for off-line analysis, I stopped tracking.

It's possible there are more people who started off tracking where the pennies go, and kept it up until they noticed it was only pennies.

Yeah just watching the kWh cost doesn't really prepare you for capacity loss - you really need to charge from VLBW or lower to 100 to get that baseline. For most people that will take a deliberate effort. It took me months to not freak out at LBW - let alone VLBW.

 

[DaveEV]

GreenCarReports has this tidbit of information today: Nissan Leaf To Get Better Battery, No News On Capacity Loss

“We’ve tested a number of individual vehicles and will be contacting those owners to discuss their individual results in the near term,” Nissan spokesperson Katherine Zachary told us on Friday.

“We also anticipate having more information to release to the wider Arizona customer base soon," she continued. "We are taking Phoenix customer concerns seriously and are working hard to ensure their full satisfaction.”

 

[dsh]

TickTock,

Ar you going to report the 1 bar loss again to Nissan LEAF and also re-update the Wiki Table?

This morning i re-lost my #12 capacity bar. I had charged to 80% overnight and had all 12 at the end of that charge when I hit the timer override to get a full charge so the bar was lost during the 80-100 charge.

Are you going to report it to Nissan? Interested to hear what they say about the loss so soon after the reset.

 

[tokenride]

Okay

I opened the case number with Nissan: 457256 with Eric.

They provided no information on what there plan is and almost seemded like I was bothering them or wasting their time. I would not say outright rude but just really monotone and non careing about the issue.

I then went to the dealer to see if the could diagnose the battery. Being that the battery is not covered under warranty. They wanted to charge me $80. I declined the offer and drove back home.

Litigation is the only option at this point. Unless Nissan wants to go to a jury trial they should settle like most companies do.

 

[cwerdna]

Okay

I opened the case number with Nissan: 457256 with Eric.

They provided no information on what there plan is and almost seemded like I was bothering them or wasting their time. I would not say outright rude but just really monotone and non careing about the issue.

I then went to the dealer to see if the could diagnose the battery. Being that the battery is not covered under warranty. They wanted to charge me $80. I declined the offer and drove back home.

Litigation is the only option at this point. Unless Nissan wants to go to a jury trial they should settle like most companies do.

Thanks! You probably recall my post (which happened to be a response to your post) at http://www.mynissanleaf.com/viewtopic.php?f=30&t=8802&p=225668&hilit=toyota#p225668" onclick="window.open(this.href);return false;.

Of course they're not going to say anything right now. Until Nissan has something to do say that's been cleared by their PR people and lawyers, they likely won't say anything, esp. given that there's at least one class action lawsuit probably coming.

I've worked in a large company for a long time and have seen the results of emails and evidence (some damaging) coming out in trials during the discovery process. There are many current examples of it and ones even involving that company I worked for.

 

[tokenride]

Okay

I opened the case number with Nissan: 457256 with Eric.

They provided no information on what there plan is and almost seemded like I was bothering them or wasting their time. I would not say outright rude but just really monotone and non careing about the issue.

I then went to the dealer to see if the could diagnose the battery. Being that the battery is not covered under warranty. They wanted to charge me $80. I declined the offer and drove back home.

Litigation is the only option at this point. Unless Nissan wants to go to a jury trial they should settle like most companies do.

Thanks! You probably recall my post (which happened to be a response to your post) at http://www.mynissanleaf.com/viewtopic.php?f=30&t=8802&p=225668&hilit=toyota#p225668" onclick="window.open(this.href);return false;.

Of course they're not going to say anything right now. Until Nissan has something to do say that's been cleared by their PR people and lawyers, they likely won't say anything, esp. given that there's at least one class action lawsuit probably coming.

I've worked in a large company for a long time and have seen the results of emails and evidence (some damaging) coming out in trials during the discovery process. There are many current examples of it and ones even involving that company I worked for.

Thank you cwerdna!

This site is a wealth of info and you guys doing all the footwork are much appreicated. I haven't given up on electric yet but we do need piece of mind on battery life.

I heard the Volt battery has a prorated warranty are they holding up so far??