Capacity Loss on 2011-2012 LEAFs

[TomT]

That is why it says "quote..." I thought adding it here would get more appropriate exposure...
In any event, I edited it to make it more clear...

Not cool copying someone else's post as your own.

 

[TomT]

Except that we know that the Leaf battery is highly influenced by the temperature climate in which it lives, whereas the Tesla battery, due to TMS among other things, is not nearly as much affected... Thus, the Tesla owner's results are much more likely to be applicable across a much wider percentage of vehicles...

That guy is like the TaylorSFGuy of the LEAF world. TaylorSFGuy's battery was down around 15% at 75k miles. You would expect it compared to a Tesla pack over 3x the size...

 

[DaveEV]

Except that we know that the Leaf battery is highly influenced by the temperature climate in which it lives, whereas the Tesla battery, due to TMS among other things, is not... Thus, the Tesla owner's results are much more likely to be applicable across a much wider percentage of vehicles...

Except that you have all sorts of owners reporting similar amounts loss after a year regardless of actual miles driven.

Decreasing rated range.
Almost 1300 posts in 9 months. Wide variations in reported loss. Some blaming BMS. Etc. Very similar to the LEAF after a year or two, but really only more noticeable because a 10 mile loss is much easier to see with the "rated range" or "ideal range" DTE indicator you can use in the Tesla. If they only had a GOM like us, there'd be a lot more speculation going on.

 

[TomT]

Perhaps - I'm not privy to that information - but a very big question of interest is how much that tracks with location and heat... Is Phoenix death and the coastal NW nirvana like it is for a Leaf???

Except that you have all sorts of owners reporting similar amounts loss after a year regardless of actual miles driven.

 

[RegGuheert]

The Tesla battery packs seem to be holding up much better than the LEAF battery packs.

This Tesla owner claims to have lost only 7% after driving 75,000 miles.

That guy is like the TaylorSFGuy of the LEAF world. TaylorSFGuy's battery was down around 15% at 75k miles. You would expect it compared to a Tesla pack over 3x the size...

Another way to put that is that TaylorSFGuy lost 3.15 kWh of capacity in 75k miles while the Model S owner lost 5.6 kWh of capacity in the same number of miles. And TaylorSFGuy had to put 2X to 3X the number of cumulative cycles on the pack (and cycled it further each time) to drive the same distance. Of course, with high miles driven in a cool climate, TaylorSFGuy is very close to the optimum case for a 2011 LEAF in terms of capacity loss per mile driven. Nearly every other 2011 LEAF in existence will lose more capacity in 75,000 miles than that one did. I wonder if the Model S experience is close to typical.

 

[smkettner]

So the average Tesla does as well as the #1 optimal LEAF in perfect conditions?
My LEAF had lost over 20% in 45,000 miles and 32 months.

 

[pchilds]

My LEAF has lost 19% in 20k miles, in 10k miles it lost 11%. Under the same conditions, my RAV4 EV lost ~1.7% in 10k miles.

 

[eHelmholtz]

My LEAF has lost 19% in 20k miles, in 10k miles it lost 11%. Under the same conditions, my RAV4 EV lost ~1.7% in 10k miles.

The summer is coming; will you be losing more bars in Temecula?

 

[pchilds]

What do you think? I am not going to air condition my garage and I will be driving/parking the LEAF in 118 deg f weather. I only drive the RAV4 EV when the LEAF won't do the job.

 

[edatoakrun]

My LEAF has lost 19% in 20k miles, in 10k miles it lost 11%...

I believe that the greatest documented loss of capacity in a LEAF over 10,000 miles was for 2012 LEAF #2183, which lost ~9.5 % of its "new" capacity between April and July of 2013 during the Phoenix torture test after being discharged from "100%" to dead, then DC recharged to "100%", twice each day, resulting in an average battery temperature of ~104 F while charging, over the entire period.

http://avt.inl.gov/pdf/energystorage/DCFC_Study_FactSheet_50k.pdf" onclick="window.open(this.href);return false;

You think perhaps your LEAFs LBC might have been exaggerating your capacity loss, by just a bit? when it reported "11%" over 10 k miles?

 

[Stoaty]

You think perhaps your LEAFs LBC might have been exaggerating your capacity loss, by just a bit? when it reported "11%" over 10 k miles?

You think it makes a difference to the driver who can only get X miles out of the Leaf before hitting Turtle?

 

[eHelmholtz]

What do you think? I am not going to air condition my garage and I will be driving/parking the LEAF in 118 deg f weather. I only drive the RAV4 EV when the LEAF won't do the job.

At that rate you may lose 4 bars before the new and improved heat resistant battery becomes available. ;-)

 

[DaveEV]

You think perhaps your LEAFs LBC might have been exaggerating your capacity loss, by just a bit? when it reported "11%" over 10 k miles?

You think perhaps 10k miles in 3 months is not necessarily the same as 10k miles over a year? :roll:

There's been plenty of cases of LEAFs losing a bar in ~1 year and ~10k miles when subjected to desert heat conditions. In fact, if you look at the wiki, there's plenty that beat that benchmark by far.

 

[edatoakrun]

You think perhaps your LEAFs LBC might have been exaggerating your capacity loss, by just a bit? when it reported "11%" over 10 k miles?

You think perhaps 10k miles in 3 months is not necessarily the same as 10k miles over a year? :roll:...

Obviously, we will not know the actual rate of calendar loss until many years have passed.

But, if you look at the data I linked previously:
http://avt.inl.gov/pdf/energystorage/DCFC_Study_FactSheet_50k.pdf" onclick="window.open(this.href);return false;

You will see that one of the 10k segment with the lowest capacity loss was the longest in time, October '13 to March '14. What you also can see from the average battery temperature data is how driving more miles per day raises the battery temperature and accelerates capacity loss. As the miles driven daily by the four LEAFs has decreased, so has both average battery temperature and rate of capacity loss.

One of the reasons I see TaylorSFguy's 112k+ miles as very good news it that by driving so many miles in so short of a time, he has probably maintained an average battery temperature ~like one of a warm California climate LEAF driven a more typical number of miles per year.

But as the Phoenix AVTA data shows, only very high battery temperatures over an extended period cause rapid capacity lose/kWh throughput. The 10k test segments with (seasonally) lower average battery temperatures show much slower rates of capacity loss.

So you evidently need a combination of very high ambient temps, very high kWh use and miles driven per day (and perhaps, as exacerbated in the AVTA test, by extreme cycling of SOC) to degrade a battery to 70% EOL by 60k or 70k miles over a short time period.

Unfortunately, we don't have data over any longer time periods, since, AFAIK, no one has done an accurate range/capacity test of a LEAF with either 4 bar loss or high miles.

The only range test of an 8 capacity bar LEAF, AFAIK, reports that Blue494, with ~38% LBC indicated capacity loss, went 59.3 miles, which we now know (from all the AVTA test data) is only ~22% less miles than the average capacity of the four "new" LEAFs tested by AVTA would have completed (~21 kWh x ~3.6 m/kwh) = ~75.6 miles.

Unfortunately, the wiki continues to use the incorrect 4.0 m/kWh, and so, an incorrect total miles, for a "new" LEAF, in it's summary.

http://electricvehiclewiki.com/Battery_Capacity_Loss" onclick="window.open(this.href);return false;

="drees"...There's been plenty of cases of LEAFs losing a bar in ~1 year and ~10k miles when subjected to desert heat conditions. In fact, if you look at the wiki, there's plenty that beat that benchmark by far.

Yes, there is plenty of data showing rapid loss of gids and bars.

But not data showing this correlates to actual capacity loss.

If Pchilds lives in Temecula as another comment suggests, his LEAF sees about the same Summer temperatures mine does. Warm, but nothing at all like Phoenix.

You think perhaps your LEAFs LBC might have been exaggerating your capacity loss, by just a bit? when it reported "11%" over 10 k miles?

You think it makes a difference to the driver who can only get X miles out of the Leaf before hitting Turtle?

Well, it makes a difference to me that "X miles" on my car in my most recent range test was 105.4 miles to ~VLBW, plus an unknown number of additional miles available to turtle.

http://www.mynissanleaf.com/viewtopic.php?f=27&t=7022&start=700" onclick="window.open(this.href);return false;

If I really thought my battery had degraded ~19.5% as indicated by my LBC, I would be very concerned.

Since my own capacity/range tests, as well as the test results from the AVTA, show the possibility of my LBC's report of ~19.5% capacity loss being correct to be remote, I'm not.

 

[RegGuheert]

Obviously, we will not know the actual rate of calendar loss until many years have passed.

This statement implies a *huge* assumption that calendar losses in the LEAF are so low that they will not be discernible for many years. While I wish it were true, I believe this assumption to be false since we have seen many LEAFs with low miles exhibit nearly as much capacity loss as those with high mileage (within in the same climate).

Unfortunately, the testing which you are referencing does not give any indication of how much loss is due to calendar loss versus cycling loss since they did not provide a control LEAF which was not driven (or was driven minimally) during the test period.

All that said, I am still intrigued by the idea that the instrumentation which is used to calculate efficiency is changing with time It may just be wishful thinking on my part. Your range tests are interesting evidence that may be happening. Is there some way that we can discern whether your efficiency really *has* increased or whether it is been the same but instrumentation has changed or some combination of both?

 

[DaveEV]

Since my own capacity/range tests, as well as the test results from the AVTA, show the possibility of my LBC's report of ~19.5% capacity loss being correct to be remote, I'm not.

A range test alone does not reflect capacity loss and if you are claiming that the car's gauges can't be relied upon, you certainly can't claim that CARWINGs data can be relied upon either.

That said, my own measurements of energy used to charge the car have directly correlated with the car's reported capacity loss and so has everyone else's.

We all know that the LEAF was over enthusiastic in estimating capacity loss in hot weather (hence the AZ cars in the big range test that went significantly farther than expected), that's one of the things the P3227 update was designed to fix.

Anyway, I an very certain that if your P3227 updated car is reporting ~20% capacity loss, it will also take ~20% less energy from the wall than a new car to fully recharge from turtle to 100%. It's been confirmed multiple times that a new car will take about 25 kWh from the wall to fully charge, so a car down 20% will take about 20 kWh. Note that charging is about 85% efficient so 25 kWh from the wall leaves you with 21 kWh usable and 20 kWh from the wall leaves you with 17 kWh usable.

 

[pchilds]

If Pchilds lives in Temecula as another comment suggests, his LEAF sees about the same Summer temperatures mine does. Warm, but nothing at all like Phoenix.

The daily highs are over 100f from June to Sept, and we get two to three weeks of over 115f in the summer. It was 90f yesterday and will be hotter today. It is funny how you manipulate everything to try and deny the failure of the LEAF battery chemistry.

 

[edatoakrun]

Obviously, we will not know the actual rate of calendar loss until many years have passed.

This statement implies a *huge* assumption that calendar losses in the LEAF are so low that they will not be discernible for many years. While I wish it were true, I believe this assumption to be false since we have seen many LEAFs with low miles exhibit nearly as much capacity loss as those with high mileage (within in the same climate).

I don't believe that that is correct. When you look at the results of the 11 LEAFs driven at the Tempe range test, the correlation between miles driven and range loss looks stronger than the correlation between gid loss and range loss, which was shown to be very weak.

The most extreme gid error was in Blue744 with 9 bars 33% loss of gids, but which actually showed a (calculated) 72.3 mile range, only ~ 3.3 miles short of the expected ~75.6 miles, only a ~4.4% loss from the ~average expected range.

http://electricvehiclewiki.com/Battery_Capacity_Loss" onclick="window.open(this.href);return false;

="RegGuheert"...Unfortunately, the testing which you are referencing does not give any indication of how much loss is due to calendar loss versus cycling loss since they did not provide a control LEAF which was not driven (or was driven minimally) during the test period...

Again, the Tempe range test does give you a crude control.

Unfortunately, that test was fairly rudimentary, omitting battery temperature controls, Carwings efficiency (regen) reports, and recharge kWh.

And, unfortunately, AFAIK, no further and more accurate tests of actual capacity using the AVTA range and Efficiency data for comparison have been conducted since.

="RegGuheert...All that said, I am still intrigued by the idea that the instrumentation which is used to calculate efficiency is changing with time It may just be wishful thinking on my part. Your range tests are interesting evidence that may be happening. Is there some way that we can discern whether your efficiency really *has* increased or whether it is been the same but instrumentation has changed or some combination of both?

Probably not enough capacity loss on My LEAF yet to get very meaningful results from a constant speed test, without knowing the efficiency increase to expect from my LEAF now having 29k on factory tires.

You can't measure total capacity loss when the variables of available capacity, and vehicle/driver efficiency exceed the miles lost, as looks to me the case for at least eight of the eleven LEAFs in the Tempe test, which, despite large gid and bar losses, either slightly exceeded the expected "new" AVTA range, or whose lost miles were within the cumulative uncertainties.

Accurate testing of four-bar losers in hot, warm, and (when TaylorSFguy loses his fourth bar) cool climates
in comparison with the AVTA reports could give some good info, IMO. And I'm still sticking with my guess of ~two years back, that the hotter the climate, the greater the gid/capacity bar error.

WHY NOT GIVE IT A TRY?

Before Nissan replaces your battery...

 

[edatoakrun]

...my own measurements of energy used to charge the car have directly correlated with the car's reported capacity loss and so has everyone else's...

You keep making the same claim drees, without offering any supporting data.

Do you have any?

quote="drees"...We all know that the LEAF was over enthusiastic in estimating capacity loss in hot weather (hence the AZ cars in the big range test that went significantly farther than expected), that's one of the things the P3227 update was designed to fix...

If the P3227 update actually "fixed" gid/capacity bar error, then it looks like most of the Tempe test LEAFs should have gained (and kept) from one to three capacity bars, after the update.

As perhaps would many other LEAFs, which does not seem to have been the case.

I haven't had the update myself, and am still considering whether to have it done at my three year battery test. BTW, I noticed a typo in my previous post. My LEAF has ~27 k miles on it, and on the OE tires.

I plan to range test both before and after both replacing the tires this fall, and before and after the P3227, to see what effects each has on efficiency, range, and in (for the p3227) changes in available capacity.

If Pchilds lives in Temecula as another comment suggests, his LEAF sees about the same Summer temperatures mine does. Warm, but nothing at all like Phoenix.

The daily highs are over 100f from June to Sept, and we get two to three weeks of over 115f in the summer. It was 90f yesterday and will be hotter today. It is funny how you manipulate everything to try and deny the failure of the LEAF battery chemistry.

Well then I guess you don't live in Temecula, since according to:

http://en.wikipedia.org/wiki/Temecula,_California" onclick="window.open(this.href);return false;

Temecula is not nearly as hot as where you live.

Which is...where?

My temperatures (at ~2,000 ft.) average ~ 5 F degrees cooler than Redding in the summer, which itself looks to average ~ 5 F hotter than Temecula, in the summer.

http://en.wikipedia.org/wiki/Redding,_California" onclick="window.open(this.href);return false;

 

[pchilds]

Well then I guess you don't live in Temecula, since according to:

http://en.wikipedia.org/wiki/Temecula,_California" onclick="window.open(this.href);return false;

Temecula is not nearly as hot as where you live.

Which is...where?

My temperatures (at ~2,000 ft.) average ~ 5 F degrees cooler than Redding in the summer, which itself looks to average ~ 5 F hotter than Temecula, in the summer.

http://en.wikipedia.org/wiki/Redding,_California" onclick="window.open(this.href);return false;

I am 7 miles from Temecula, my thermometer is not calibrated. But I find it hard to believe that it is out by 10-15 degs f, maybe 5 degs f.