sandeen
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Leaf Number: 026685
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Dramatic Ahr rise after quick charge?

Tue Aug 22, 2017 11:43 am

I've seen a few references to this effect, but wondering if people can share what they've seen in detail.

I'm tracking my 2012 leaf, hoping I get a 4 bar drop by the end of Jan 2018. Last week, I felt like I was getting within striking distance - I had dropped to 43.66Ahr, and was feeling pretty good about my chances. I hadn't quick charged for over a month.

Then yesterday I quick-charged to nearly full after hitting LBW. My Ahr jumped to 43.83. Then my wife drove the car for 30 miles today ... 43.87Ahr. A 0.2Ahr jump in a day seems very large. Is this a normal effect? How long have people seen it last? Is this a temporary blip or does it reset the curve, so to speak?

Here's what Ahr did as compared to SOC over the last 2 days; the rapid increase in SOC is the quick charge, of course:
Image

After one quick charge session back in June I saw my Ahr jump and not drop back to the prior values for almost 2 weeks. I hope that doesn't happen this time, as I'm getting awfully close to missing my warranty expiration. :( Sigh.

Anecdote or not, I think I'm done with quick charging until my warranty period is over. :(
2012 SL from TX, (mfg 8/12), used, dropped to 8 bars at 43.50 Ahr, 40,601 miles. my daily stats =/= my collected data on 4-bar losers

SageBrush
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Location: Colorado

Re: Dramatic Ahr rise after quick charge?

Tue Aug 22, 2017 12:32 pm

You are acting on noise. QC every day.
2013 Model 'S' with QC & rear-view camera
Bought off-lease Jan 2017 from N. California with 63.9 Ahr after 22k miles
Car is now enjoying an easy life in Colorado

sandeen
Posts: 113
Joined: Fri May 12, 2017 1:45 pm
Leaf Number: 026685
Location: Minnesota

Re: Dramatic Ahr rise after quick charge?

Tue Aug 22, 2017 5:35 pm

Another 30 miles, now it's 43.94 Ahr.

I know what you mean about noise, but I've never seen a gain like this so quickly, based on the last 4-5 months of driving. This is well outside the norm as far as I can tell.
2012 SL from TX, (mfg 8/12), used, dropped to 8 bars at 43.50 Ahr, 40,601 miles. my daily stats =/= my collected data on 4-bar losers

sandeen
Posts: 113
Joined: Fri May 12, 2017 1:45 pm
Leaf Number: 026685
Location: Minnesota

Re: Dramatic Ahr rise after quick charge?

Tue Aug 22, 2017 10:44 pm

Now up to 44.09.
Image
This looks like a bit more than noise ... steady downward trend for 1000 miles, now this.
2012 SL from TX, (mfg 8/12), used, dropped to 8 bars at 43.50 Ahr, 40,601 miles. my daily stats =/= my collected data on 4-bar losers

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drees
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Re: Dramatic Ahr rise after quick charge?

Wed Aug 23, 2017 12:20 am

Eric, what were your charging habits before your recent QC?

I've logged some 0.7 AHr jumps after QC, but it quickly goes back down. 80% charges and shallow discharges seem to suppress AHr readings, QCs and/or full discharge/charge cycles seem to help pump them up temporarily.

You're still on track to lose that bar in time, I wouldn't stress about it that much. Just keep on driving it - you have plenty of miles left.

BTW, did your Hx value jump, too? The times I saw AHr jump, HX remained the same.
'11 LEAF SL Powered By 3.24 kW Enphase Solar PV

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RegGuheert
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Re: Dramatic Ahr rise after quick charge?

Wed Aug 23, 2017 4:38 am

drees wrote:BTW, did your Hx value jump, too? The times I saw AHr jump, HX remained the same.
It did. See the graph above your post.
RegGuheert
2011 Leaf SL Demo vehicle
2011 miles at purchase. 10K miles on Apr 14, 2013. 20K miles (55.7Ah) on Aug 7, 2014, 30K miles (52.0Ah) on Dec 30, 2015, 40K miles (49.8Ah) on Feb 8, 2017.
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DaveinOlyWA
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Re: Dramatic Ahr rise after quick charge?

Wed Aug 23, 2017 6:13 am

you should QC more often, as much as possible to be realistic. Keep in mind; losing that last capacity bar is your prompt to get the battery tested. its that test that determines whether you get a replacement. generally you are good but if your numbers are depressed then you might not fail (to qualify) the test. I am fairly certain you would not be the first.

The ahr is not jumping, the counter is simply off. you can do the same thing by doing several full charges and deep discharges over several days. Realize if you want degradation, heat is what you need so QC in Summer is the fastest way to get that heat buildup
2011 SL; 44,598 miles. 2013 S; 44,840 miles.2016 S30 (build 10/2016)"low water marks" 24,858.2 miles.363 GIDAhr 80.66Hx95.95%kwh28.1QCs215,L2's 227
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SageBrush
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Re: Dramatic Ahr rise after quick charge?

Wed Aug 23, 2017 6:34 am

DaveinOlyWA wrote:you should QC more often, as much as possible to be realistic. Keep in mind; losing that last capacity bar is your prompt to get the battery tested. its that test that determines whether you get a replacement. generally you are good but if your numbers are depressed then you might not fail (to qualify) the test. I am fairly certain you would not be the first.

The ahr is not jumping, the counter is simply off. you can do the same thing by doing several full charges and deep discharges over several days. Realize if you want degradation, heat is what you need so QC in Summer is the fastest way to get that heat buildup

1+
2013 Model 'S' with QC & rear-view camera
Bought off-lease Jan 2017 from N. California with 63.9 Ahr after 22k miles
Car is now enjoying an easy life in Colorado

sandeen
Posts: 113
Joined: Fri May 12, 2017 1:45 pm
Leaf Number: 026685
Location: Minnesota

Re: Dramatic Ahr rise after quick charge?

Wed Aug 23, 2017 7:29 am

drees - I had been charging almost exclusively on L1 for over a month, last DCQC was mid-July. (2 reasons: The L1 charger cord is the one that reaches past my wife's van to my parking spot, and I only drive about 20 miles/day, so quick charge doesn't make a ton of sense). And yes, both Ahr & Hx went up, they stayed in their otherwise linear relationship. As for plenty of time - well, I have plenty of miles, not so much time. :)

DaveinOlyWA - are there really any established reports of a 4 bar loss that was not warrantied due to "not bad enough?" I think I've seen one denial in these forums because Nissan somehow determined the battery had been abused, but I don't remember any other such denial.

And yes, I agree it's more likely an accounting/measurement change than an actual battery health change, but on the other hand, there have been no reports of 4th bar loss above 43.5 Ahr, so I certainly don't want to take a long excursion back up above 44, for example. :)

Thanks,
-Eric
2012 SL from TX, (mfg 8/12), used, dropped to 8 bars at 43.50 Ahr, 40,601 miles. my daily stats =/= my collected data on 4-bar losers

sandeen
Posts: 113
Joined: Fri May 12, 2017 1:45 pm
Leaf Number: 026685
Location: Minnesota

Re: Dramatic Ahr rise after quick charge?

Wed Aug 23, 2017 7:10 pm

Hm. Of those who reported QC counts at 4th bar loss, the mean was 46 QCs and the median was 8 QCs. It doesn't seem like too many people quick-charged their battery to death.
OTOH, the average miles per L1/L2 charge at 4 bar loss is 16.
2012 SL from TX, (mfg 8/12), used, dropped to 8 bars at 43.50 Ahr, 40,601 miles. my daily stats =/= my collected data on 4-bar losers

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