lorenfb
Posts: 2474
Joined: Tue Dec 17, 2013 10:53 pm
Delivery Date: 22 Nov 2013
Leaf Number: 416635
Location: SoCal

Re: The 40KWH Battery Topic

Fri May 10, 2019 6:27 am

SageBrush wrote:
lorenfb wrote:
SageBrush wrote:
What you say makes sense: if baseline heat generation in the battery is say 2% of the power draw then a 25% increase in resistance would presumably (?) increase heat generation up to 2*1.25 = 2.5% of the power draw. No big deal.
above is battery power loss - from an increase in battery resistance only
SageBrush wrote: But then I start from
P = I*I*R and I conclude that an increase in R to R1 would lead to a drop in I = sqrt (R/R1)
Then e.g., an increase in R of 25% would lead to a drop in I to sqrt(0.75) = 86.6%
above is total power loss - from a total load resistance increase

You're confusing the two different situations.
I'm obviously being dense about this, thanks for the patience.

If I just consider the battery in isolation, is my use of I*I*R correct ?
That is, does an increase of R to R1 reduce the current to sqrt(R/R1) ?
Yes, for a short circuit test of the battery, i.e. you connect the two terminals of the battery together (no load) and the battery resistance
increased. Typically the resistance would decrease as it heated. Or you used to different external resistors and did that test.
#1 Leaf SL MY 9/13: 76K miles, 47 Ahrs, 5.0 miles/kWh (average), Hx=70, SOH=73, L2 - 100% > 1000, temp < 95F, (DOD) > 20 Ahrs
#2 Leaf SL MY 12/18: 10.3K miles, SOH 109Ahrs/115Ahrs, 5.2 miles/kWh (average), DOD > 20%, temp < 105F

SageBrush
Posts: 5377
Joined: Sun Mar 06, 2011 2:28 am
Delivery Date: 13 Feb 2017
Location: NM

Re: The 40KWH Battery Topic

Fri May 10, 2019 9:11 am

lorenfb wrote:
SageBrush wrote:
lorenfb wrote:
above is battery power loss - from an increase in battery resistance only



above is total power loss - from a total load resistance increase

You're confusing the two different situations.
I'm obviously being dense about this, thanks for the patience.

If I just consider the battery in isolation, is my use of I*I*R correct ?
That is, does an increase of R to R1 reduce the current to sqrt(R/R1) ?
Yes, for a short circuit test of the battery, i.e. you connect the two terminals of the battery together (no load) and the battery resistance
increased. Typically the resistance would decrease as it heated. Or you used to different external resistors and did that test.
:: light bulb ignites ::
I think I finally get it

(R1 - R) acts as a additional serial resistor in my simple circuit
2013 LEAF 'S' Model with QC & rear-view camera
Bought Jan 2017 from N. California
Two years in Colorado, now in NM
03/18: 58 Ahr, 28k miles
11/18: 56.16 Ahr, 30k miles
09/20: 54.3 Ahr; 38k miles
-----
2018 Tesla Model 3 LR, Delivered 6/2018

kovadam
Posts: 30
Joined: Wed Jun 06, 2018 12:07 am
Delivery Date: 28 Sep 2018
Location: Hungary, Europe

Re: The 40KWH Battery Topic

Mon May 13, 2019 12:21 am

Hi!

Strange thing happened in the last two days. From Saturday to Sunday the SOH dropped from 96.91% to 96.70%, then from Sunday to Monday the SOH dropped to 97.48%. Without any reason.
The car was not QC-d, the battery was not overheated, I charged using L1 charger (220V/10A) from Friday to Saturday to 92% SOC (from around 40-50%, used 8 hours of charging with the charge timer) and did not even use the car on the weekend, despite this, the SOH dropped 0.5%. Also Hx dropped from 114.58% to 114.23%.

Funny thing, that with a full charge I still get over 97% capacity, if I check the GIDs. I still can charge over 485 GIDS (488-490 some times, which is 97.6-97.8%, for a couple weeks ago I was able to charge till 38.1kWh capacity, which is way over 98%) which is 97.4% or above, and over 37kWh estimated capacity.

I think SOH & Hx are totally wrong with the new Leaf, and since the battery chemistry is totally different from the previous models, also the values mean totally different things, or are not even meaning anything regarding SOH, they are only some numerical data read from the CAN and interpreted as SOH, because it showed some correlation between bar lost and SOH value drop in the past, but only Nissan Engineers know what this values mean.

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

Re: The 40KWH Battery Topic

Mon May 13, 2019 12:36 am

Strange thing happened in the last two days. From Saturday to Sunday the SOH dropped from 96.91% to 96.70%, then from Sunday to Monday the SOH dropped to 97.48%. Without any reason.
That last number is higher, not lower...

I agree that Hx is now useless (if it was ever really useful) but SOH seems to still be valuable, at least if you don't count very small changes as significant. BTW, if the above increase with the last number isn't a typo, that would be, I think, the first rise in SOH for a 40kwh pack we've seen.
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: 15148
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 May 13, 2019 6:21 am

kovadam wrote:Hi!

Strange thing happened in the last two days. From Saturday to Sunday the SOH dropped from 96.91% to 96.70%, then from Sunday to Monday the SOH dropped to 97.48%. Without any reason.
The car was not QC-d, the battery was not overheated, I charged using L1 charger (220V/10A) from Friday to Saturday to 92% SOC (from around 40-50%, used 8 hours of charging with the charge timer) and did not even use the car on the weekend, despite this, the SOH dropped 0.5%. Also Hx dropped from 114.58% to 114.23%.

Funny thing, that with a full charge I still get over 97% capacity, if I check the GIDs. I still can charge over 485 GIDS (488-490 some times, which is 97.6-97.8%, for a couple weeks ago I was able to charge till 38.1kWh capacity, which is way over 98%) which is 97.4% or above, and over 37kWh estimated capacity.

I think SOH & Hx are totally wrong with the new Leaf, and since the battery chemistry is totally different from the previous models, also the values mean totally different things, or are not even meaning anything regarding SOH, they are only some numerical data read from the CAN and interpreted as SOH, because it showed some correlation between bar lost and SOH value drop in the past, but only Nissan Engineers know what this values mean.
Well, when it happens again in approximately 90 days, it will be less strange. My Hx is over 120
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; 14,342.8 mi, 93.16% SOH
My Blog; http://daveinolywa.blogspot.com" onclick="window.open(this.href);return false;

Jerryr
Posts: 77
Joined: Mon May 14, 2018 8:18 am
Delivery Date: 12 May 2019
Leaf Number: 310009
Location: Bradenton, Florida

Re: The 40KWH Battery Topic

Mon May 13, 2019 6:54 am

Just as a point of reference. My brand 2019 SL Plus w/62 kWh battery, manufacture date 2/19. 46 miles on odometer after driveling it home from dealership.

Image

Image
2019 SL Plus 5/19- current
2018 SV w/tech and All Weather pkg 5/18-4/19 (traded)
2015 SL 4/15-5/18 (traded)
2019 Ford F-350 Lariat Ultimate CCSB SRW Diesel
2015 Lexus RX450h
2017 Grand Design RV 337RLS 5th wheel

kovadam
Posts: 30
Joined: Wed Jun 06, 2018 12:07 am
Delivery Date: 28 Sep 2018
Location: Hungary, Europe

Re: The 40KWH Battery Topic

Mon May 13, 2019 7:25 am

Sorry, it was a typo, 96.48, but after I left work in afternoon it was only 96.41%, so within 10 hours it dropped again 0.07% without any reason, the Hx dropped again a bit. Will see how this evolves, the car is 6 months old and has around 14000km on ODO.

LeftieBiker
Moderator
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Joined: Wed May 22, 2013 3:17 am
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Location: Upstate New York, US

Re: The 40KWH Battery Topic

Mon May 13, 2019 1:59 pm

Just as a point of reference. My brand 2019 SL Plus w/62 kWh battery, manufacture date 2/19. 46 miles on odometer after driveling it home from dealership.
The 98.96 SOH may be an indication that the 62kwh pack loses capacity at at least the same rate as the 40kwh pack. Where do you live, Jeryr?
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.

Jerryr
Posts: 77
Joined: Mon May 14, 2018 8:18 am
Delivery Date: 12 May 2019
Leaf Number: 310009
Location: Bradenton, Florida

Re: The 40KWH Battery Topic

Mon May 13, 2019 3:12 pm

LeftieBiker wrote:
Just as a point of reference. My brand 2019 SL Plus w/62 kWh battery, manufacture date 2/19. 46 miles on odometer after driveling it home from dealership.
The 98.96 SOH may be an indication that the 62kwh pack loses capacity at at least the same rate as the 40kwh pack. Where do you live, Jeryr?
Tampa Florida area.
2019 SL Plus 5/19- current
2018 SV w/tech and All Weather pkg 5/18-4/19 (traded)
2015 SL 4/15-5/18 (traded)
2019 Ford F-350 Lariat Ultimate CCSB SRW Diesel
2015 Lexus RX450h
2017 Grand Design RV 337RLS 5th wheel

LeftieBiker
Moderator
Posts: 15742
Joined: Wed May 22, 2013 3:17 am
Delivery Date: 30 Apr 2018
Location: Upstate New York, US

Re: The 40KWH Battery Topic

Mon May 13, 2019 3:13 pm

Thanks. That's helpful information.
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.

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