Turning Over a New LEAF: My Response to a Lost Capacity Bar

DANandNAN said:

OrientExpress said:

Personally my take on the current hysteria over the batteries is that I wonder what will happen when the weather cools off this fall and the missing bars come back?

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Do you have reports of that happening last year? Some folks have lost 2 bars, surely they would have lost 1 bar last year and then had it reappear as the weather cooled and the battery regenerated. Are there any posts about that?

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From October to February last year, I gained back about 2kWh (~10%) capacity so I do think it is possible for someone who is on the edge to get the top bar back, and likely that someone who lost more than one to get one back.

mwalsh said:

... It is too early to be freaking out. It's a concern, yes. And a bit of a gamble at this point too. But we really do have to wait and see what happens beyond the losses already seen. ...

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Actually, this thread shows that people DON'T have to wait and see if they don't want to. It IS a gamble after all. It may be that six months from now, word will have gotten around and there may be a huge depreciation on these lost capacity cars...or it may be no big deal.

TickTock said:

From October to February last year, I gained back about 2kWh (~10%) capacity so I do think it is possible for someone who is on the edge to get the top bar back, and likely that someone who lost more than one to get one back.

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If it is possible to recover 10% of capacity, then it is conceivable for a LEAF to recover two capacity bars. It will be interesting to see if anyone actually recovers bars or not. I am not aware of any reports of that to date.

RegGuheert said:

TickTock said:

From October to February last year, I gained back about 2kWh (~10%) capacity so I do think it is possible for someone who is on the edge to get the top bar back, and likely that someone who lost more than one to get one back.

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If it is possible to recover 10% of capacity, then it is conceivable for a LEAF to recover two capacity bars. It will be interesting to see if anyone actually recovers bars or not. I am not aware of any reports of that to date.

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Not to quibble semantics with TickTock, but I doubt his LEAF "gained back" capacity. I think it's far more likely that his LEAFs battery management, allowed him to charge to a higher percentage of the Battery's existing capacity, once climate conditions permitted.

And this would imply that many who have lost a bar, may not have lost a full 15% of battery capacity, but that their own LEAF's may be similarly restricting charge levels, under present hot conditions, to prevent rapid capacity loss.

I don't think you could expect it likely to see reports of any cars gaining significant "gids", much less of having any bars reappear, until this fall, from LEAFs located in the Northern hemisphere.

I'm still waiting for further confirmation of, and more details on, the only (?) "lost two bars" report.

...Not reported by owner, but by others:
1. Opossum has reported of two cars in Phoenix that have lost 2 bars...

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http://www.mynissanleaf.com/viewtopic.php?f=30&t=8802&start=920" onclick="window.open(this.href);return false;

edatoakrun said:

I'm still waiting for further confirmation of, and more details on, the only (?) "lost two bars" report.

...Not reported by owner, but by others:
1. Opossum has reported of two cars in Phoenix that have lost 2 bars...

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http://www.mynissanleaf.com/viewtopic.php?f=30&t=8802&start=920" onclick="window.open(this.href);return false;

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That is not the only report anymore. leafkabob posted the following late yesterday:

leafkabob said:

After I dropped my 12th bar at the end of May, I asked a co-worker with a leaf if she had all 12 bars. She said she had not checked but did get dinged on her annual battery check for charging to 100% too often. Today she called me and said that she is down to 10 bars! :shock:

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It seems confirmed that some LEAFs are reporting over 20% capacity loss in 1/4 the amount of time that Nissan stated would be the norm. If the capacity bars function somehow differently than how Nissan has explained them then we should find this out later in the year.

edatoakrun said:

Not to quibble semantics with TickTock, but I doubt his LEAF "gained back" capacity. I think it's far more likely that his LEAFs battery management, allowed him to charge to a higher percentage of the Battery's existing capacity, once climate conditions permitted.

And this would imply that many who have lost a bar, may not have lost a full 15% of battery capacity, but that their own LEAF's may be similarly restricting charge levels, under present hot conditions, to prevent rapid capacity loss.

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That would be another classical example of how ignorance creates fear....
I am curious though how the bars would come back???
Thermodynamic processes of the kind that degrade the battery are usually irreversible?

If your theory holds (lower capacity bars= temporary temperature dependent battery protection) one would wonder why

a) Nissan would have stated that right away in response to the loss...this would have been such a graceful explanation

b) Last year in Phoenix (when it was hot too) no bars where lost?

Since neither a) nor b) have been confirmed, it seems unlikely that this is the case and bars come back from the dead...

klapauzius said:

edatoakrun said:

Not to quibble semantics with TickTock, but I doubt his LEAF "gained back" capacity. I think it's far more likely that his LEAFs battery management, allowed him to charge to a higher percentage of the Battery's existing capacity, once climate conditions permitted.

And this would imply that many who have lost a bar, may not have lost a full 15% of battery capacity, but that their own LEAF's may be similarly restricting charge levels, under present hot conditions, to prevent rapid capacity loss.

Click to expand...

That would be another classical example of how ignorance creates fear....
I am curious though how the bars would come back???
Thermodynamic processes of the kind that degrade the battery are usually irreversible?

If your theory holds (lower capacity bars= temporary temperature dependent battery protection) one would wonder why

a) Nissan would have stated that right away in response to the loss...this would have been such a graceful explanation

b) Last year in Phoenix (when it was hot too) no bars where lost?

Since neither a) nor b) have been confirmed, it seems unlikely that this is the case and bars come back from the dead...

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I agree that we have not established that dropped capacity bars are tied to max gids (available charge), but there was a clear increase in the gids measured for a 100% charge as weather got cooler. If capacity bars *are* tied to max capacity then it is reasonable to expect one or more to come back this fall. It actually appears, based on the slope of the red dots when I started logging, that my level may have been even lower prior to October when I recieved my gidometer. The red dots below are the gids measured for a 100% charge times 80Wh. Blue is the same but for an 80% charge.

TickTock said:

I agree that we have not established that dropped capacity bars are tied to max gids (available charge), but there was a clear increase in the gids measured for a 100% charge as weather got cooler. If capacity bars *are* tied to max capacity then it is reasonable to expect one or more to come back this fall. It actually appears, based on the slope of the red dots when I started logging, that my level may have been even lower prior to October when I recieved my gidometer. The red dots below are the gids measured for a 100% charge times 80Wh. Blue is the same but for an 80% charge.

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Interesting...can you make a scatter plot of gids vs. average daily temperature?

klapauzius said:

TickTock said:

I agree that we have not established that dropped capacity bars are tied to max gids (available charge), but there was a clear increase in the gids measured for a 100% charge as weather got cooler. If capacity bars *are* tied to max capacity then it is reasonable to expect one or more to come back this fall. It actually appears, based on the slope of the red dots when I started logging, that my level may have been even lower prior to October when I recieved my gidometer. The red dots below are the gids measured for a 100% charge times 80Wh. Blue is the same but for an 80% charge.

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Interesting...can you make a scatter plot of gids vs. average daily temperature?

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Good idea. Here you go based on daily max and min temps according to wunderground.

Nice. That looks almost like a linear relationship.
No idea if the chemistry/physics of the battery produce this or if this is an artificial, i.e.
the BMS of the LEAF. If it was the BMS, zombie-bars could be possible....

If that were the case, why has no one lost a bar last summer? Or maybe its a combination of degradation AND the heat induced BMS actions?
You would think that NISSAN has studied the battery under all kinds of conditions, so they should know the things
we find out with our hobby science approach here...So they could just tell everyone about the mechanics of the whole thing
and people would be at least less anxious.

Given the whole layout of the LEAF they apparently think that LESS information is LESS anxiety producing. Which makes an implicit assumption about
the IQ of the user, where I think they might be wrong (at least as far as early adopters go).

klapauzius said:

Nice. That looks almost like a linear relationship.
No idea if the chemistry/physics of the battery produce this or if this is an artificial, i.e.
the BMS of the LEAF.

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I believe that we would expect something like what's depicted on the graph below from a raw LiMnO4 cell. It's almost an inverse relationship when compared to the plot posted earlier. The biggest question right now is, where do the 281 Gids come from? Please have a look at this and this, if it was of interest.

Here's a somewhat promising graph. I added the daily temperature to the historical graph. If you squint your eyes while looking at it, it does appear I am getting slightly lower full charge capacities at the same temperature as last year but that delta is smaller than the annual variation. Of course there may be some hysteresis masking some of the degradation...

[Edit: Replaced graph with one including time top bar was lost]

SanDust said:

You can BTW extend for six months assuming it's a Nissan lease.

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Whatchutalkinboutwillis?

TickTock-

Can place on your graph, the date on which your 12th bar dissapeared?

quote="klapauzius"]

edatoakrun said:

Not to quibble semantics with TickTock, but I doubt his LEAF "gained back" capacity. I think it's far more likely that his LEAFs battery management, allowed him to charge to a higher percentage of the Battery's existing capacity, once climate conditions permitted.

And this would imply that many who have lost a bar, may not have lost a full 15% of battery capacity, but that their own LEAFs may be similarly restricting charge levels, under present hot conditions, to prevent rapid capacity loss.

Click to expand...

That would be another classical example of how ignorance creates fear....
I am curious though how the bars would come back???
Thermodynamic processes of the kind that degrade the battery are usually irreversible?

Reply by edatoakrun: There is no evidence that the bars accurately (and only) represent "Thermodynamic processes of the kind that degrade the battery".

I have no idea of whether the seasonal increase in capacity TickTock observed last year by gid counts, presumably due to the BMS allowing charging to a greater % of total battery capacity, will result in the twelfth bar "reappearing" on any LEAF dashes in the future.

If your theory holds (lower capacity bars= temporary temperature dependent battery protection) one would wonder why

a) Nissan would have stated that right away in response to the loss...this would have been such a graceful explanation

Reply by edatoakrun: Nissan has had a policy of NOT making any detailed comments on battery capacity from Day 1 of the LEAF launch.

Whatever the Legal or PR reasoning behind this policy, I doubt it will change much in the immediate future.


b) Last year in Phoenix (when it was hot too) no bars where lost?

Reply by edatoakrun: The battery bars may display available battery capacity, both as reduced permanently by degradation, and also as temporarily restricted by the BMS. Presumably, even TickTocks LEAF, which had the lowest total documented battery capacity, had enough battery capacity remaining, to keep the 12th bar on display.

Since neither a) nor b) have been confirmed, it seems unlikely that this is the case and bars come back from the dead...

Reply by edatoakrun: You are correct, neither have been confirmed, and Ticktock's gid reports have not yet been corroborated by others with gid counters. I hope more LEAF/gid meter owners will post their observations. I really don't think you should be too concerned about whether your 12th bar comes back or not, as long as your battery capacity has not been permanently degraded by between 15% and 21%, which is what many seem to believe 11 bars definitively shows.

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Shrink; i have not read the 4 pages of posts but your post has really made my day.

your premise started out as how disappointing the Leaf was but then you bought another one anyway. i dont think that even Nissan could have done a better job of illustrating just how much the "EV driving" factor plays into the ownership picture.

and i also am in the camp that capacity loss is not linear. i drove a Zenn which is completely different. it used lead acid batts which lose about 5-10% capacity right away, then the loss slows down a lot.

now, i figured my Leaf would lose 5-10% which in the first 10-15,000 miles or a year or so then taper off to 1-2 % a year making about 20% after 5 years, 75,000 miles right??.

well, i havent lost anything yet so Nissan has greatly outperformed my fondest expectations.

now, i also think that Nissan knew about AZ temp issues and was banking on it not being a major owner issue until the TN batt plant was able to pump out spare packs.

so, ya i think Nissan will do the right thing

TickTock said:

Here's a somewhat promising graph. I added the daily temperature to the historical graph. If you squint your eyes while looking at it, it does appear I am getting slightly lower full charge capacities at the same temperature as last year but that delta is smaller than the annual variation. Of course there may be some hysteresis masking some of the degradation...

[Edit: Replaced graph with one including time top bar was lost]

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Thanks.

I don't want to sound too pessimistic, but it looks like you could be pretty close to losing bar #11, if that occurs when the "old" Nissan manual reports, at 21.25% reduction?

turbo2ltr: Wow, I just realized according to the gauge, my capacity has dropped 6.25% in exactly 6 weeks to the day. That's a rather alarming rate. (2nd bar turns off at 78.75%). I haven't even driven 1000 miles since losing the first bar.

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http://www.mynissanleaf.com/viewtopic.php?f=30&t=8802&start=930" onclick="window.open(this.href);return false;

edatoakrun said:

I don't want to sound too pessimistic, but it looks like you could be pretty close to losing bar #11, if that occurs when the "old" Nissan manual reports, at 21.25% reduction?

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I believe that will happen at 208 Gids. Yes, his Leaf appears to be getting close. It might take a month or two at this rate, if he were to hit that milestone this summer.

Any ideas about the linear relationship between capacity and temperature? It seems definitely
not in line with normal battery behavior, so is this some sign of artificial (i.e. BMS) intervention?

Or did it just happen so that the decline in capacity coincided with the steady rise in temps over the course
of this year?
Anyway, if a capacity bar ever came back, that would be a big deal and we would read about it first on this forum...

Given reports of more bar losses , i.e. down to 10 out of 12, I would think that something should happen soon. Even Nissan cannot
brush this off as normal anymore?

If everyone wants to chip in for my electric bill, I'll charge my car in my air conditioned shop for the next week and see if I get a bar back.. lol

LTLFTcomposite said:

SanDust said:

You can BTW extend for six months assuming it's a Nissan lease.

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Whatchutalkinboutwillis?

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You can extend the lease for six months at the same rate.