jdcbomb
Posts: 211
Joined: Tue May 19, 2015 12:17 pm
Delivery Date: 18 May 2015

Re: The 40KWH Battery Topic

Tue Jun 11, 2019 6:12 am

Why did the Hx value in my 40 kWh start off in the mid 90's and now with a SOH of 95.70 the Hx is around 113. Is there any technical reason?
2018 SL - In Service 2019 JUN - 2019 OCT 96.7 SOH
2018 SV - In Service 2019 JAN - Location: Raleigh, NC - 2019 OCT 93.7 SOH
2013 SL - In Service 2013 FEB, Sold 2018 JUN (50,050 mi) - 4 Bars Lost (44,255 mi)

DaveinOlyWA
Posts: 14204
Joined: Sat Apr 24, 2010 7:43 pm
Delivery Date: 16 Nov 2019
Leaf Number: 319862
Location: Olympia, WA
Contact: Website

Re: The 40KWH Battery Topic

Tue Jun 11, 2019 6:19 am

jdcbomb wrote:Why did the Hx value in my 40 kWh start off in the mid 90's and now with a SOH of 95.70 the Hx is around 113. Is there any technical reason?
Yes there is a technical reason but specifics can only be supposed.

I "think" the change in chemistry and resulting change in resistance values has caused the higher than normal reading. My Hx has been between 118-119 for months now.
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; 412 mi, 99.72% SOH
My Blog; http://daveinolywa.blogspot.com" onclick="window.open(this.href);return false;

lorenfb
Posts: 2272
Joined: Tue Dec 17, 2013 10:53 pm
Delivery Date: 22 Nov 2013
Leaf Number: 416635
Location: SoCal

Re: The 40KWH Battery Topic

Tue Jun 11, 2019 7:47 am

DaveinOlyWA wrote:
jdcbomb wrote:Why did the Hx value in my 40 kWh start off in the mid 90's and now with a SOH of 95.70 the Hx is around 113. Is there any technical reason?
Yes there is a technical reason but specifics can only be supposed.

I "think" the change in chemistry and resulting change in resistance values has caused the higher than normal reading. My Hx has been between 118-119 for months now.
Nissan most likely didn't modify the algorithm that calculated Hx (the ratio of the battery's conductances - present/initial) based
on the later batteries, e.g. using the older batteries' initial conductance value which would cause Hx to be greater than 100%.
#1 Leaf SL MY 9/13: 74K miles, 48 Ahrs, 5.2 miles/kWh (average), Hx=70, SOH=78, L2 - 100% > 1000, temp < 95F, (DOD) > 20 Ahrs
#2 Leaf SL MY 12/18: 4.5K miles, 115 Ahrs, 5.5 miles/kWh (average), Hx=98, SOH=99, DOD > 20%, temp < 105F

goldbrick
Posts: 634
Joined: Tue Aug 01, 2017 3:33 pm
Delivery Date: 01 Aug 2017
Leaf Number: 311806
Location: Boulder, CO

Re: The 40KWH Battery Topic

Wed Jun 12, 2019 5:20 am

lorenfb wrote:
DaveinOlyWA wrote:
jdcbomb wrote:Why did the Hx value in my 40 kWh start off in the mid 90's and now with a SOH of 95.70 the Hx is around 113. Is there any technical reason?
Yes there is a technical reason but specifics can only be supposed.

I "think" the change in chemistry and resulting change in resistance values has caused the higher than normal reading. My Hx has been between 118-119 for months now.
Nissan most likely didn't modify the algorithm that calculated Hx (the ratio of the battery's conductances - present/initial) based
on the later batteries, e.g. using the older batteries' initial conductance value which would cause Hx to be greater than 100%.
Are you sure that is the algorithm used to calculate Hx? I find it hard to imagine that while reprogramming the BMS for the new models that the value of the initial conductance (a constant) wasn't changed. As far as I know, no one here really knows what Hx means. Like the old adage "those that know don't say and those that say don't know". It will be interesting to see what happens to Hx values as the 40kWh and 60kWh packs age but practically speaking, what difference does it make? Does it affect charge rate, regen rate, or anything meaningful at all?

lorenfb
Posts: 2272
Joined: Tue Dec 17, 2013 10:53 pm
Delivery Date: 22 Nov 2013
Leaf Number: 416635
Location: SoCal

Re: The 40KWH Battery Topic

Wed Jun 12, 2019 8:01 am

goldbrick wrote:
lorenfb wrote: Nissan most likely didn't modify the algorithm that calculated Hx (the ratio of the battery's conductances - present/initial) based
on the later batteries, e.g. using the older batteries' initial conductance value which would cause Hx to be greater than 100%.
Are you sure that is the algorithm used to calculate Hx?
1. It appears to be a percentage, e.g. 0 - 100%.
2. It tracks SOH, i.e. declines as the battery ages.
3. It does agree with the inverse of the ratio of the battery resistance over time.
4. It provides additional insight into battery degradation over time.

My 2013 battery resistance over time:

12/27/14 - 14,800 miles, 103 mohms per LeafDD, 11 deg, 24% SOC
3/10 - 17,400 miles, 60 mohms per LeafDD, 30 deg, 73% SOC
3/14 - 17, 550 miles, 56 mohms per LeafDD, 32 deg, 47% SOC
4/14 - 19,100 miles, 59 mohms per LeafDD, 25 deg. 38% SOC
5/4 - 19,989 miles, 64 mohms per LeafDD, 24 deg. 48% SOC
5/15 - 20,400 miles, 73 mohms per LeafDD, 20 deg. 41% SOC
5/22 - 20,700 miles, 58 mohms per LeafDD, 28 deg. 50% SOC
12/10/15 - 28,000 miles, 90 mohms per LeafDD, 19 deg. 92% SOC
4/5 - 32,000 miles, 74 mohms per LeafDD, 24 deg, 55% SOC
5/16 - 33,700 miles, 89 mohms per LeafDD, 22 deg, 47% SOC
5/16 - 33.700 miles, 58 mohms per LeafDD, 31 deg, 76% SOC
10/5 - 39,300 miles, 100 mohms per LeafDD, 22 deg, 50% SOC
10/6 - 39,400 miles, 61 mohms per LeafDD, 30 deg, 51% SOC
10/7 - 39,500 miles, 80 mohms per LeafDD, 25 deg, 56% SOC
10/15 - 40,000 miles, 71 mohms per LeafDD, 27 deg, 45% SOC
10/30 - 41,000 miles, 74 mohms per LeafDD, 23 deg, 66% SOC
12/26/16 - 43,000 miles, 110 mohms per LeafDD, 13 deg, 77% SOC
6/10/17 - 49,600 miles, 89 mohms per LeafDD, 19 deg, 70% SOC
7/1/17 - 51,000 miles, 62 mohms per LeafDD, 33 deg, 44% SOC
8/15/17 - 53,400 miles, 61 mohms per LeafDD, 35 deg, 57% SOC
4/2/18 - 62,100 miles, 110 mohms per LeafDD, 18 deg, 94% SOC
6/13/18 - 65,000 miles, 84 mohms per LeafDD, 26 deg, 52% SOC
8/13/18 - 67,000 miles, 80 mohms per LeafDD, 26 deg, 91% SOC
9/14/18 - 68,000 miles, 84 mohms per LeafDD, 27 deg, 57% SOC

And you have a better assumption?
#1 Leaf SL MY 9/13: 74K miles, 48 Ahrs, 5.2 miles/kWh (average), Hx=70, SOH=78, L2 - 100% > 1000, temp < 95F, (DOD) > 20 Ahrs
#2 Leaf SL MY 12/18: 4.5K miles, 115 Ahrs, 5.5 miles/kWh (average), Hx=98, SOH=99, DOD > 20%, temp < 105F

EnigmaEV
Posts: 21
Joined: Mon May 07, 2018 9:52 am
Delivery Date: 31 Mar 2018
Leaf Number: 301349
Location: Saskatchewan, Canada

Re: The 40KWH Battery Topic

Sun Jul 07, 2019 8:24 am

After 15 months of regular, fairly consistent decreases in SOH, LeafSpy has reported my first INCREASE in SOH. I started out at 93.95% on July 5th and ended the day at 94.09%. Yesterday it dropped the regular 0.01% to 94.08%. There was nothing significantly different about the driving or charging I did on the 5th - 49 km driven, pack temperature 20-22C, SOC near 50%, no charging. We don't have any L3 chargers within 500 km so I have never rapid charged it. It gets charged to 100% twice a week just prior to a 100 km trip.

Has anyone else seen an increase in SOH with a 40 kWh pack? I know it was common with 24 and 30 kWh packs, particularly after a rapid charge, but I have not read/heard about any 40 kWh packs that have shown an increase in SOH.

Degradation seems to have slowed significantly as the pack has aged. SOH dropped from 99.57% to 94.84% (4.73%) in the first 6 months with 12,000 km (7,500 mi) driven. In the 9 months since (includes 6 months of winter) I have driven 16,000 km (10,000 mi) with SOH only dropping from 94.84% to 94.08% (0.76%). If this trend continues, the longevity of the 40 kWh pack might be pretty good - at least in a cool/cold climate - and if you can trust the data provided by the BMS.
2018 Leaf SL, 35,632 km, SOH - 93.66%, Hx - 117.29, AHr - 108.121

LeftieBiker
Moderator
Posts: 13419
Joined: Wed May 22, 2013 3:17 am
Delivery Date: 30 Apr 2018
Location: Upstate New York, US

Re: The 40KWH Battery Topic

Sun Jul 07, 2019 12:03 pm

I haven't seen an increase, and haven't read of one before yours. My own experience was a disturbing drop in SOH the first 6 months, then virtually no drop over the first Winter and Spring, resulting in a first year drop of about 4.6%, IIRC. I haven't checked it this Summer.
Scarlet Ember 2018 Leaf SL W/ Pro Pilot
2009 Vectrix VX-1 W/18 Leaf modules, & 3 EZIP E-bicycles.
BAFX OBDII Dongle
PLEASE don't PM me with Leaf questions. Just post in the topic that seems most appropriate.

SageBrush
Posts: 4907
Joined: Sun Mar 06, 2011 2:28 am
Delivery Date: 13 Feb 2017
Location: NM

Re: The 40KWH Battery Topic

Sun Jul 07, 2019 12:48 pm

LeftieBiker wrote: I haven't checked it this Summer.
A tried and true method to stop LEAF battery degradation.
2013 LEAF 'S' Model with QC & rear-view camera
Bought off-lease Jan 2017 from N. California
Two years in Colorado, now in NM
03/2018: 58 Ahr, 28k miles
11/2018: 56.16 Ahr, 30k miles
-----
2018 Tesla Model 3 LR, Delivered 6/2018

LeftieBiker
Moderator
Posts: 13419
Joined: Wed May 22, 2013 3:17 am
Delivery Date: 30 Apr 2018
Location: Upstate New York, US

Re: The 40KWH Battery Topic

Sun Jul 07, 2019 1:53 pm

A little less snark would be appreciated. I decided after the last reading that 6 month intervals would be sufficient.
Scarlet Ember 2018 Leaf SL W/ Pro Pilot
2009 Vectrix VX-1 W/18 Leaf modules, & 3 EZIP E-bicycles.
BAFX OBDII Dongle
PLEASE don't PM me with Leaf questions. Just post in the topic that seems most appropriate.

DaveinOlyWA
Posts: 14204
Joined: Sat Apr 24, 2010 7:43 pm
Delivery Date: 16 Nov 2019
Leaf Number: 319862
Location: Olympia, WA
Contact: Website

Re: The 40KWH Battery Topic

Mon Jul 08, 2019 5:16 am

SOH rise is unique. I have seen a single "point" (.01%) rise during the day that negated itself by the next morning (only record data in morning or before first drive of the day)

As far as my loss, its settled into a pattern of a relatively large chunk lost every 90 days. Because of this rather predictable pattern, I have varied both charging and driving habits to see if anything affected this 90 day cycle and nothing has so far.

I am a few days to maybe a week to my next "adjustment" so we shall see what happens.
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; 412 mi, 99.72% SOH
My Blog; http://daveinolywa.blogspot.com" onclick="window.open(this.href);return false;

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