Capacity Loss on 2011-2012 LEAFs

[surfingslovak]

Wk of 5/14/12, 260-265

My last 281 was on 3/26/12. I'm currently in mourning for My 281! It was nice while it lasted.

Some stats: After 11.5 mo., I have 16600 mi on the odo. I've QC'd 5-6x off Mitsubishi's Eaton DC QC. I received all 5 Stars on my Battery Inspection report at 15k mi. on 4/21/12.

JP, thank you for sharing this! Would you know what your Gid count is after an 80% charge?

 

[LEAFfan]

Losing 15%+ capacity each year will suck pond water come year 3 or 4.

Seq Yr	Year	Capacity %	Degradation	Range	"5% Temp 
Boost"
1	2011	100.00	15%	73	77
2	2012	85.00	15%	62	65
3	2013	72.25	15%	53	55
4	2014	61.41	15%	45	47
5	2015	52.20	15%	38	40
6	2016	44.37	15%	32	34
7	2017	37.71	15%	28	29
8	2018	32.06	15%	23	25
9	2019	27.25	15%	20	21
10	2020	23.16	15%	17	18
11	2021	19.69	15%	14	15
12	2022	16.73	15%	12	13
13	2023	14.22	15%	10	11
14	2024	12.09	15%	9	9
15	2025	10.28	15%	8	8

The battery capacity bars aren't linear, so it isn't 15% per year, but a capacity bar per year or 15,000 miles, whichever comes first. The second bar is about another 6% loss.

 

[JPWhite]

It may be colder here in winter than in Ireland but Colorado is pretty mild compared to places like Norway. Cold weather matters.

No Maybe about it Their average low in January is 25. Positively balmy for you guys up the mountain there.

Nevertheless, I agree that seasonal variations in range have nothing to do with permanent loss of battery capacity in very hot weather areas. I, too, hope that Nissan will do the right thing and take care of the Phoenix LEAF owners.

You and me both.

I am buoyed by the fact Nissan took car of early owners of vehicles with CVT's. The repair costs were very high and after enough customer complaints Nissan retroactively applied a longer warranty on the transmissions and refunded owners who had already paid the exorbitant repair costs.

It maybe necessary for Nissan to hear loud and clear from the Phoenix owners they are unhappy before they are alerted to a potential PR and reputation issue with the LEAF. It will take enough official complaints before they act however. I wouldn't think they'd jump on the problem until it was clear to all and sundry that there is a problem. I doubt a 'hint' of a problem would be enough for them to act. It won't take Nissan's awareness of the technical issue to act, but rather the threat to their reputation and ability to sell EV's going forward.

 

[JPWhite]

The battery capacity bars aren't linear, so it isn't 15% per year, but a capacity bar per year or 15,000 miles, whichever comes first. The second bar is about another 6% loss.

I'm not sure I buy into that. If that were the case how come Steve Marsh has done almost 40,000 miles and as far as I know hasn't lost a capacity bar yet.

I think you have been told porky pies.

 

[surfingslovak]

The battery capacity bars aren't linear, so it isn't 15% per year, but a capacity bar per year or 15,000 miles, whichever comes first. The second bar is about another 6% loss.

I'm not sure I buy into that. If that were the case how come Steve Marsh has done almost 40,000 miles and as far as I know hasn't lost a capacity bar yet.

To be fair, I've heard elsewhere that capacity loss for the Leaf is supposed to be non-linear. The source said that the loss will level off after a large initial hit. Be that as it may, I have not seen this behavior in the data I have gathered from other EVs. There was an NREL report referenced on the forum last year, which projected the annual capacity loss to be about 2% for moderate climates, and 4% for hot climates, such as Arizona.

What Steve Marsh has seen, is consistent with the MINI-E field trial report from Tom Moloughney, which I shared on the forum last October. For what it's worth, my Leaf is approaching 11K, and I have hardly seen any degradation at all. If treated right, I expect this early trend that to continue.

As to the capacity bars: LEAFfan is correct, they are non-linear. The same can be said of the battery temperature gauge. I wish Nissan would simply show a number, than to play games, and dumb it down the way they did.

 

[JPVLeaf]

JP, thank you for sharing this! Would you know what your Gid count is after an 80% charge?

You're welcome. My last 3-4 charges to 80%, I've gotten 218 Gids.

Also, for the few 100% charges so far this wk, the decline in my Gids seems to have settled compared the declines I've logged over the past 5-6 wks.

Wk of 5/21/12, 260-264

I can't draw any conclusions yet, but I now notice that the rise and fall appears to correspond to rise and fall of high temps. The city where I work/charged had temps in the mid- to high-80's during the two weeks in April and May that I had the lowest Gid readings at 100%. Those are 'low' temps as inland goes for So Cal, so it makes me wonder what readings I will get once it starts hitting the 90's here like it has in summers past.

Also, as a precaution based on what I've been reading here, I modified my charging during the day by going to 80% first, then setting the timer to go to 100% about 1-1/2 hr before done time. So it only sits ~1/4 hr before I need to hit the road. Not sure how long I'm gonna play this routine, especially if the effect is more driven by amb temp and my mild temp variations (non-AZ 100+F temps) are likely not entirely permanent battery degrades. We'll see. Maybe I'll just save this 80/100 combo routine for the really hot days (90-100+F). It's bit of a hassle to do this daily.

Since I've only had my Gid-meter since Oct last yr., I'm looking forward to getting numbers during the coming summer months. None of us have had our Gid meters through a full summer, so we shall see. Also, until proven otherwise, I'm hoping at least some of my lower Gids to be temp-driven variations. How much, I'm not sure. For now, I'm considering my lower Gids (crossing fingers) within the noise/normal ... and in a different class than the bar-losing, -15%, 110+°F folks.

 

[tbleakne]

I'm also seeing an unusual and abrupt capacity loss, though only about 3%, actually 9 Gids, and of course I haven't lost a capacity bar.

I usually charge to 100% and I've been able to get 281 Gids routinely, with drops down to 278 or so occurring often. But I got a couple of 281 readings early this month. Now, suddenly, I'm only able to get 272 Gids, which reads as 96.7%. I tried charging to 80% for one night, then back to 100% the next night, but still got only 272 at 100%.

I always set a start timer only and leave the J plug in for hours after the charge completion, so there's ample time for balancing.

It seems quite possible that your good experience until recently, better than mine with less mileage, is lower temperatures, particularly while charging.

I have first achieved 280 or 281 for my rare 100% charge after cooler weather began last Fall. Lately PM max temperatures in my garage reach 83-84, and sometimes AM min temperatures are as high as 67 deg F. I installed an insulated garage door just before I took delivery, and I am using a fan to cool off the garage as much as possible over night. For this summer I am planning to "bite-the-bullet" and very occasionally top-off my charge at peak time in the afternoon just before I head out to minimize the time the pack sits at 100% in hot conditions.

 

[leafkabob]

Even though I have not lost a capacity bar, I reported here a few days ago about my charging habits because I fully expect to lose a bar soon. I figured I may as well keep it all in this thread. After my last post, LEAFfan kindly offered to scan my car with his scangauge. He came over this morning after an overnight 100% charge (followed by a 6 hour cell balancing period) and his gauge read 81.1%! I realize his gauge is not a Gidometer, and I can't recall how to convert that reading to gids, but whatever it is, it doesn't look good.

I don't charge to 100 much, try to charge overnight at the coolest time of the day (3-5:30 am) and have never QC'd. And still it looks like I am very near to losing a bar. 9500 miles on the car after exactly 12 months of driving.

I suspect that my car may be similar to Tick Tock's in that it may have read low from the beginning. I also suspect that there are many more folks out there whose cars fit that description, but they don't know it because they have never put a gauge on their car.

For what it is worth, after Leaffan's scan, I immediately drove to my dealer for my 12 month battery check. Of course I got 5 stars. I asked for a copy of the new owner's manual but they would not give me one unless I get the software update from a couple of months ago (which I have not yet done).

 

[LEAFfan]

The battery capacity bars aren't linear, so it isn't 15% per year, but a capacity bar per year or 15,000 miles, whichever comes first. The second bar is about another 6% loss.

I'm not sure I buy into that. If that were the case how come Steve Marsh has done almost 40,000 miles and as far as I know hasn't lost a capacity bar yet.
I think you have been told porky pies.

LOL, you'll be eating those porky pies because I doubt Steve Marsh lives in Phoenix, so it will happen. And he may not have lost a bar yet, but he will. He could be at a 14% capacity loss right now and not even realize it if he doesn't have a BCM like mine. If you don't believe that the bars aren't linear, just look in your manual. I'm pretty sure it shows the percentage for each bar. After the first 15%, most are 6% or 7% losses.

 

[surfingslovak]

LOL, you'll be eating those porky pies because I doubt Steve Marsh lives in Phoenix, so it will happen. And he may not have lost a bar yet, but he will. He could be at a 14% capacity loss right now and not even realize it if he doesn't have a BCM like mine. If you don't believe that the bars aren't linear, just look in your manual. I'm pretty sure it shows the percentage for each bar. After the first 15%, most are 6% or 7% losses.

LEAFfan, I have referenced our wiki in my post above. The first capacity bar is 15% and every subsequent one is 6.25%. That said, I have to ask you to keep the tone civil, and not to spread misinformation, and sometimes even wild speculation. Steve Marsh has recently put Gary's meter to use, and has confirmed that his battery is within 3% of nominal capacity.

I did my best to track all the reports, and we seem to have several cars in Phoenix at about 20% projected capacity loss, two in Texas at 10%, two in SoCal at 8%, and everyone else is at 5% or better. We should get a larger data collection and tabulate it online, it would remove some of the speculation, guesswork and uncertainty.

 

[JPVLeaf]

I did my best to track all the reports, and we seem to have several cars in Phoenix at about 20% projected capacity loss, two in Texas at 10%, two in SoCal at 8%, and everyone else is at 5% or better. We should get a larger data collection and tabulate online, it would remove some of the speculation, guesswork and uncertainty.

To add to the data pool, I took my Gid-meter this past week to three other Leafs after completing a '100%' charge and got the following:

1. 7.5 mos, 8600 mi., 269 Gids (95.7%), 5x charges/wk from 60% to 100% overnight, Orange Cty.
2. 7 mos, 7500 mi., 269 (95.7%), 4-5x charges/week from ~25% to 100% thru mid-day, San Bern Cty (inland So Cal).
3. 10.5 mos, 10000 mi., 265 (94.3%), 4-5x charges/week from ~40% to 100% thru mid-day, San Bern Cty (inland So Cal).

My charging pattern is closer to #2. Considering my higher mileage, I'm not feeling too bad about my recent 260-265's. But, if a later dip into the 250's doesn't correspond to a rise in the day's temp, ....

 

[shrink]

I'm in Phoenix and LEAFan also came by my place today for a reading. Thanks again, BTW.

Anyway, at 100% charge by 3:45am (from 6 bars the night before) and a reading taken at 8:00am LEAFan's scan gauge read 85.7%.

Got my car on 8/6/2011 and mileage at the time of the reading was 9378 miles.

Then I went out to run errands and put 82 miles on the car utilizing 1-hour of L2 at a public Blink and a QC that took the charge (per the Blink DCQC) from 40% to 80% in 13 minutes.

 

[leafkabob]

There's no way at 11 capacity bars that it will be even close to 94-95%. I know my SoC gauge isn't exact, but I'd be willing to bet that it's damn close. Basing it on 281 is not much different than actual SoC%. Right now, I have a 10-12% capacity loss and the SoC shows only about 78-79% after a 100% DCQC. Using L2, it may charge to a little more. A long time ago, after charging to 100% with L2, it did reach 100% ONE time, but mostly was between 93% and 97%. With DCQC, it used to reach 93-94%, but now it shows less than 80% after a 100% charge.
But it will be interesting to see if the capacity losses level off in the next couple years or so.

You DO NOT have an SoC gauge, because the number you read is based on watt-hours after some math. If your capacity drops, then the watt-hours drop. You can still have a maximum state of charge regardless of capacity. Thus, a car with 50% capacity would read roughly 50% SoC on your scangauge even if fully charged, even though you'd still 12 SoC bars (6 capacity bars), and Carwings would still show 100%.

If I were you, I'd reprogram the formula on your Scangauge's Xgauge to read watt-hours (multiply by 80) or gids (no math needed), because calling it SoC is wrong.

-Phil

Phil, I'm confused as to what Leaffan's gauge means. He put it on my car this morning after a 100% charge and it read 81.1%. Can I say for certain that I have lost approximately 13% capacity, or does it not work that way?

Leaf-"Not an Engineer"-Kabob

 

[surfingslovak]

Phil, I'm confused as to what Leaffan's gauge means. He put it on my car this morning after a 100% charge and it read 81.1%. Can I say for certain that I have lost approximately 13% capacity, or does it not work that way?

Leafkabob, the modified ScanGauge LEAFfan is using displays your Gid count as a percentage of 281. According to what Phil told us earlier, this corresponds to a coulomb-count of the energy that has flown into the battery. Nissan calls Gids stored watt-hours, and each unit corresponds to 80 Wh. It's roughly the energy needed to let a regular lightbulb burn for about an hour.

 

[leafkabob]

Phil, I'm confused as to what Leaffan's gauge means. He put it on my car this morning after a 100% charge and it read 81.1%. Can I say for certain that I have lost approximately 13% capacity, or does it not work that way?

Leafkabob, the modified ScanGauge LEAFfan is using displays your Gid count as a percentage of 281. According to what Phil told us earlier, this corresponds to a coulomb-count of the energy that has flown into the battery. Nissan calls Gids stored watt-hours, and each unit corresponds to 80 Wh. It's roughly the energy needed to let a regular lightbulb burn for about an hour.

Thank you for the reply surfingslovak. So I guess my gid count on a full charge is 228 (rounded up).

 

[surfingslovak]

Thank you for the reply surfingslovak. So I guess my gid count on a full charge is 228 (rounded up).

Yes, that's most likely what that ScanGauge readout means. If you don't mind me asking, you haven't lost a capacity bar yet, correct?

 

[leafkabob]

Thank you for the reply surfingslovak. So I guess my gid count on a full charge is 228 (rounded up).

Yes, that's most likely what that ScanGauge readout means. If you don't mind me asking, you haven't lost a capacity bar yet, correct?

Not yet, but it looks like I've lost about 13% so it will be interesting to see when it happens.

 

[Herm]

Thanks to all the people that are reporting GID readings at 100%.. dont forget to also mention how you charge the car, how often, if it ever spends time at 100%, your usual efficiency in miles/W-h and estimated temperatures the car sits in.

JPVLeaf just reported three cars in California with about 5% degradation per 10k miles..

 

[edatoakrun]

After multiple weeks of multiple reports of bar loss and gid counts, I think some fundamental information must be gathered, to put this issue in perspective.

What actual battery capacity have the 11 bar cars, and those who report lower GID counts, lost?

I believe Phil’s report that, from the LEAF-idyllic climate of Berkeley California, The LEAF make about 93% to 94% of the battery capacity available to the driver, and that charging is limited to 95%-96% of potential battery capacity, is well accepted.

I am not aware of Phil's, or anyone else's report, of tests on 11 bar or other extreme-temperature LEAFs, to see if that 95%-96% is still available, or if LEAF battery management, to protect the battery pack from degradation caused by higher charge rates in high temperatures, actually restricts the maximum charge at “100%”, to some lower percentage of the potential charge level.

In fact, the only real report of Arizona gid counts over time, that by TickTock (IIRC, please post it-too damn many threads to search!) shows just this pattern, of the battery pack accepting a higher SOC (at least as indicated by higher gid counts) in lower temperature conditions, as plotted seasonally . Others have reported, anecdotally, of higher gid counts when charging at lower (than very high) temperatures.

I have no doubt that the 11 bar cars have lost significant battery capacity from new. Every LEAF has lost some battery capacity from new, and will continue to, every year, until the battery is exchanged, or for the life of the car. But since, AFAIK, we still have no idea how the LEAF battery management reacts to high temperatures, if it limits the maximum charge in high heat conditions to protect battery life, we really don’t know what 11 bars, or lower gid counts mean, in terms of long-term loss of battery capacity.

I certainly hope that Nissan took the same prophylactic measures in limiting charging level at “100%”, that they did in other design areas, to prevent premature battery failure. Did they?

Take a look at the Phoenix daily temperature reports and graphs for the last few months here:

http://www.accuweather.com/en/us/phoenix-az/85003/april-weather/346935" onclick="window.open(this.href);return false;

How well do these higher than average temperatures, and the several occurrences of record high temperatures, correspond to your bar loss and declining gid count reports?

Those of you tracking gids in other locations might want to consider looking more closely at temperature effects as well, IMO.

 

[surfingslovak]

JPVLeaf just reported three cars in California with about 5% degradation per 10k miles..

Herm, where was that? Must have missed it. I have only there cars with less than 95% Gid reading in California: JP, Mike Walsh and Tony. Boomer and Stoaty were still above that last time I looked.