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surfingslovak
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Re: Turning Over a New LEAF: My Response to a Lost Capacity

Thu Jun 28, 2012 11:29 pm

klapauzius wrote: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.
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.Image

Image

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TickTock
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Re: Turning Over a New LEAF: My Response to a Lost Capacity

Fri Jun 29, 2012 5:32 am

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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Last edited by TickTock on Fri Jun 29, 2012 8:02 am, edited 1 time in total.

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LTLFTcomposite
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Re: Turning Over a New LEAF: My Response to a Lost Capacity

Fri Jun 29, 2012 6:37 am

SanDust wrote:You can BTW extend for six months assuming it's a Nissan lease.
Whatchutalkinboutwillis?
LTL
White 2012 SV delivered 10 Dec 2011 returned 25 Nov 2014 replaced with stopgap ICE Sentra
[35 months] [35K miles] [9 Bars]
2013 Volt replaced after 36 months/30k miles with ICE Rogue
2016 SV-adjacent May 2016 lost 4th bar March 2018

edatoakrun
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Re: Turning Over a New LEAF: My Response to a Lost Capacity

Fri Jun 29, 2012 7:14 am

TickTock-

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

quote="klapauzius"]
edatoakrun wrote:
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.
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.
no condition is permanent

DaveinOlyWA
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Re: Turning Over a New LEAF: My Response to a Lost Capacity

Fri Jun 29, 2012 9:11 am

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
2011 SL; 44,598 mi, 87% SOH. 2013 S; 44,840 mi, 91% SOH. 2016 S30; 29,413 mi, 99% SOH. 2018 S; 25,185 mi, SOH 92.23%. 2019 S Plus; 13,705 mi, 93.41% SOH
My Blog; http://daveinolywa.blogspot.com" onclick="window.open(this.href);return false;

edatoakrun
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Re: Turning Over a New LEAF: My Response to a Lost Capacity

Fri Jun 29, 2012 9:24 am

TickTock wrote: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]
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.
http://www.mynissanleaf.com/viewtopic.p ... &start=930" onclick="window.open(this.href);return false;
no condition is permanent

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surfingslovak
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Re: Turning Over a New LEAF: My Response to a Lost Capacity

Fri Jun 29, 2012 11:09 am

edatoakrun wrote: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?
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. Image

klapauzius
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Re: Turning Over a New LEAF: My Response to a Lost Capacity

Fri Jun 29, 2012 9:33 pm

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?

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

Fri Jun 29, 2012 11:08 pm

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
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SanDust
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Re: Turning Over a New LEAF: My Response to a Lost Capacity

Sat Jun 30, 2012 1:58 am

LTLFTcomposite wrote:
SanDust wrote:You can BTW extend for six months assuming it's a Nissan lease.
Whatchutalkinboutwillis?
You can extend the lease for six months at the same rate.

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