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

Re: Dramatic Ahr rise after quick charge?

Sun Aug 27, 2017 5:25 pm

Highest reading I got while I owned the car was 45.9, that was a couple weeks after I bought it (took that long to get LeafSpy set up).

I only have 2 readings from the prior owner; he wasn't so analytical. ;)

Code: Select all

Date      Miles      Ahr
06/04/16   30000      50.9
10/11/16   34000      46.3
04/17/17   36671      45.91

He (almost) never quick charged, FWIW.
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

User avatar
RegGuheert
Posts: 5547
Joined: Mon Mar 19, 2012 4:12 am
Delivery Date: 16 Mar 2012
Leaf Number: 5926
Location: Northern VA

Re: Dramatic Ahr rise after quick charge?

Sun Aug 27, 2017 5:48 pm

sandeen wrote:Highest reading I got while I owned the car was 45.9, that was a couple weeks after I bought it (took that long to get LeafSpy set up).

I only have 2 readings from the prior owner; he wasn't so analytical. ;)

Code: Select all

Date      Miles      Ahr
06/04/16   30000      50.9
10/11/16   34000      46.3
04/17/17   36671      45.91

He (almost) never quick charged, FWIW.
I suppose those numbers are believable for TX. But the car certainly had 10 bars at the time it was showing 50.9 Ah. The data you showed in your spreadsheet also indicates that the third (10th) bar never drops above 47.5 Ah.

I think you should ignore that 50.9 Ah reading and just work with the 46.3 Ah last October. That should give you a better idea of the slope you will be seeing. And as the cold weather sets in, your capacity should stop dropping (or slow significantly).
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.
Enphase Inverter Measured MTBF: M190, M215, M250, S280

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

Re: Dramatic Ahr rise after quick charge?

Sun Aug 27, 2017 6:37 pm

I have the (MN) dealer battery check from 2/3/2016, and it does show 9 bars. But yes, I take the 50Ahr reading with a grain of salt, and I'm only looking at my own data for trends. (Incidentally, I'm still 0.56Ahr above where I was before the quick charges.) As for the colder weather, yeah. :/ If I don't see a return to my prior slope soon it looks like no chance.
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

User avatar
RegGuheert
Posts: 5547
Joined: Mon Mar 19, 2012 4:12 am
Delivery Date: 16 Mar 2012
Leaf Number: 5926
Location: Northern VA

Re: Dramatic Ahr rise after quick charge?

Mon Aug 28, 2017 9:33 am

sandeen wrote:It's just that my experience and my data doesn't seem to bear that out.
Nice spreadsheet. I can see you experienced a bump in capacity when you previously QCed your LEAF, though not as big as the current one.
sandeen wrote:My own experience (QC consistently bumping Ahr up for weeks), anecdotes I've read (QC bumps, QC slowing degradation curve), and data I've collected about 4 bar losers (nobody ever loses a bar above 43.5Ahr, median reported QC count is only eight (average under 50), etc) seem to point in the other direction to some degree.
Thanks for putting together this data! That's very helpful.

Can you please add my LEAF into the '3 bar drops' tab:

Miles: 46,100
Ah: 47.47
Hx: 51.60
QC: 12
L1/L2: 2768
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.
Enphase Inverter Measured MTBF: M190, M215, M250, S280

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

Re: Dramatic Ahr rise after quick charge?

Mon Aug 28, 2017 9:36 am

RegGuheert wrote:Can you please add my LEAF into the '3 bar drops' tab


Sure thing, done. (I have not put nearly as much effort into the 3 bar drop stats, as you can see - that's water under the bridge for me, but it would be interesting to collect more data there if it's been reported).
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

User avatar
RegGuheert
Posts: 5547
Joined: Mon Mar 19, 2012 4:12 am
Delivery Date: 16 Mar 2012
Leaf Number: 5926
Location: Northern VA

Re: Dramatic Ahr rise after quick charge?

Mon Aug 28, 2017 10:27 am

sandeen wrote:
RegGuheert wrote:Can you please add my LEAF into the '3 bar drops' tab
Sure thing, done.
Thanks!
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.
Enphase Inverter Measured MTBF: M190, M215, M250, S280

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 29, 2017 8:50 pm

RegGuheert wrote:I think you should ignore that 50.9 Ah reading

I took the car in for the annual battery check today (figured that if I hope for warranty and/or goodwill, I should be sure to follow mfgr's instructions, even though the $70 hurt). Tech said no other battery check had ever been registered with Nissan, even though I have one printed out from 2016.
Anyway, I just realized that that 50.9Ahr reading was probably due to a jump right after a P3227 update after the car was bought from auction before it got resold.
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 30, 2017 12:16 pm

Aug 30: As promised, here's an updated graph of my Ahr readings about a week after the surprising quick charge jump on the 21st. I actually needed to quick charge a couple times on the 25th as well, to get through my travels; I noted that the battery got up to around 100F that day. I've overlaid the DCQC total energy in kWh for days when I quick-charged. There seems to have been some effect back in June as well, though not nearly as dramatic. Other quick charges seem to have had no effect at all. Speaking somewhat non-analytically, it appears that my quick charging behavior has had a tendency to "reset" the decline in readings to a certain degree; so far I don't see a quick return to the prior levels.

Image

I'll just update/edit this post rather than adding another, after another week or so.

Edit Sep 3: And now, a "dramatic decline" over the past four days. I'm now back at levels where I started prior to the round of DCQC, though had I continued on the trajectory I'd seen prior to the latest quick charging, my reported Ahr capacity would be even lower. We'll see what the next days bring.

Edit Sep 10: Still basically hovering around where I was prior to the fateful quick charges. Certainly not hard proof, but the trendline I was on for weeks prior to the quick charge is still really knocked off course. Nothing indicates that the quick charges and relatively high heat did anything to degrade the battery (at least as reflected in the LeafSpy readings).
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?

Mon Sep 11, 2017 7:11 pm

Readings are now finally back down below where they were prior to the quick charges:
43.65 Ahr, 45.49 Hx, 66% SOH, 40125 mi.
Trend line of Ahr decline during my ownership shows me hitting 42Ahr on my warranty end date. In February. :D Hoping my car might be a higher-Ahr-bar-loser, because it's doubtful that I'll see that capacity drop during the colder months.
I think we have 4 more hot days left this summer. :)
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?

Fri Sep 22, 2017 11:20 am

Here's another way I've been looking at this. I'm tracking my Ahr decline with a best fit curve by date, like this:
Image
Now, as my Ahr readings change over time, the target date moves. If I decline more quickly than average, it moves in, and vice versa. Now, here's a graph of my projected date of hitting 42Ahr, which was my goal for reasonable chance of dropping that bar, and with quick charge & L2 charges overlaid. Days w/ no DCQC or L2 are (likely) L1 charging, or (occasionally) no charging. There are probably a couple of L2 charges that I don't have logged from public stations.
Image
What I notice about this is that faster charging seems invariably to push my "target date" out - i.e. reduces the rate of Ahr decline. And it's not temporary. There have been some very minor moves to earlier dates, but by and large, my periods of faster charging have always reduced the rate of Ahr decline, and hence pushed out my target date. If I exclusively L1 charge, the slope stays more or less the same, and my target date remains steady. It now sits at precisely my end of warranty date. o_O
Now, it's true that the bar drop may not be governed (solely) by Ahr values. Maybe L1 charging artificially suppresses Ahr readings, but does not hasten the bar drop. But the preponderance of evidence I've seen with my car makes me think that at least the moderate amount of quick charging I have done is a net "loss" in the race for a new battery.
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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