danrjones
Posts: 782
Joined: Wed Apr 17, 2019 8:02 am
Delivery Date: 17 Jun 2019
Location: Ridgecrest, CA

Re: The 40KWH Battery Topic

Wed Sep 09, 2020 10:21 am

DougWantsALeaf wrote:
Tue Sep 08, 2020 8:06 pm
Congrats. The BMS taketh..but every once in a while giveth.
It certainly is a strange system that Nissan coded. Taking it away only to give it back, assuming we are looking at data that's actually useful and valid in the first place.

Still going up as of this AM. Will post again when the 3 month adjustment is complete.
2018 Leaf SV Pearl White with Tech and All Weather, Purchased New on 5/3/19

WetEV
Posts: 4052
Joined: Fri May 04, 2012 8:25 am
Delivery Date: 16 Feb 2014
Location: Near Seattle, WA

Re: The 40KWH Battery Topic

Wed Sep 09, 2020 12:35 pm

danrjones wrote:
Wed Sep 09, 2020 10:21 am
DougWantsALeaf wrote:
Tue Sep 08, 2020 8:06 pm
Congrats. The BMS taketh..but every once in a while giveth.
It certainly is a strange system that Nissan coded. Taking it away only to give it back, assuming we are looking at data that's actually useful and valid in the first place.

Still going up as of this AM. Will post again when the 3 month adjustment is complete.
Nothing real was taken away. The estimate changed, that's all.

SOC is an estimate. Accurate to a couple of percent at best, readout to 4 significant digits is misleading at best.
WetEV
#49
Most everything around here is wet during the rainy season. And the rainy season is long.
2012 Leaf SL Red (Totaled)
2014 Leaf SL Red
2019 eTron Blue

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

Wed Sep 09, 2020 1:18 pm

WetEV wrote:
Wed Sep 09, 2020 12:35 pm
danrjones wrote:
Wed Sep 09, 2020 10:21 am
DougWantsALeaf wrote:
Tue Sep 08, 2020 8:06 pm
Congrats. The BMS taketh..but every once in a while giveth.
It certainly is a strange system that Nissan coded. Taking it away only to give it back, assuming we are looking at data that's actually useful and valid in the first place.

Still going up as of this AM. Will post again when the 3 month adjustment is complete.
Nothing real was taken away. The estimate changed, that's all.
Right!
WetEV wrote:
Wed Sep 09, 2020 12:35 pm
SOC is an estimate. Accurate to a couple of percent at best, readout to 4 significant digits is misleading at best.
All this preoccupation with very minor anecdotal changes in SOH/SOC has little value, and any inference results in a non sequitur.
#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

danrjones
Posts: 782
Joined: Wed Apr 17, 2019 8:02 am
Delivery Date: 17 Jun 2019
Location: Ridgecrest, CA

Re: The 40KWH Battery Topic

Wed Sep 09, 2020 1:45 pm

WetEV wrote:
Wed Sep 09, 2020 12:35 pm
danrjones wrote:
Wed Sep 09, 2020 10:21 am
DougWantsALeaf wrote:
Tue Sep 08, 2020 8:06 pm
Congrats. The BMS taketh..but every once in a while giveth.
It certainly is a strange system that Nissan coded. Taking it away only to give it back, assuming we are looking at data that's actually useful and valid in the first place.

Still going up as of this AM. Will post again when the 3 month adjustment is complete.
Nothing real was taken away. The estimate changed, that's all.

SOC is an estimate. Accurate to a couple of percent at best, readout to 4 significant digits is misleading at best.
I understand that, its Nissan's system I find wonky. Why bother to sit there day by day and nibble away at it then run a algorithm every 3 months to adjust up or down. The daily nibbles can contradict the algorithm and vice versa. Those daily nibbles seem a pointless maneuver if the 3 month adjustment is going to go and overrule them.
2018 Leaf SV Pearl White with Tech and All Weather, Purchased New on 5/3/19

jmurtagh13
Posts: 25
Joined: Sun Nov 01, 2015 4:54 am
Delivery Date: 10 Mar 2018
Leaf Number: 300844
Location: Atlanta GA

Re: The 40KWH Battery Topic

Fri Sep 11, 2020 11:04 am

Image

22,186 Miles 30 months old. Last month's drop .12%, SOH 90.60

Charge only with level2 to a max of 65%. Charge early morning when it's cooler and the battery get's a chance to cool some. I don't drive aggressively so the battery temp stays below 85 deg most of the time, never above 90 deg. I feel like a I really baby the battery, yet the BMS shows about the same as others who have many more miles and do DC charging. I'm into ebikes and do the same by only charging to 65-70% and that definitely makes those batteries last a lot longer. I'm just not sure I believe the BMS, I guess more time will tell.
2018 Leaf March 10, 2018
32 months, 23,543 miles
SOH 89.59

DougWantsALeaf
Posts: 2190
Joined: Fri May 10, 2013 8:21 pm
Delivery Date: 18 May 2013
Leaf Number: 407811
Location: Chicago North Side

Re: The 40KWH Battery Topic

Fri Sep 11, 2020 11:26 am

Nice graph. Have your miles been put on fairly consistently over the past 2 1/2 years?
2019 S Plus (98.06% SOH) & 2019 SV Plus (94.77% SOH) Both Silver
2013 Leaf SV sold 2019 with 11 bars
100 Mile Club Member (Number 87)
Max Miles on 13 Leaf: 120 miles
Max Miles on 19 SV+: 242 Highway miles @ 4.5 miles/kWh

SageBrush
Posts: 5375
Joined: Sun Mar 06, 2011 2:28 am
Delivery Date: 13 Feb 2017
Location: NM

Re: The 40KWH Battery Topic

Fri Sep 11, 2020 11:59 am

jmurtagh13 wrote:
Fri Sep 11, 2020 11:04 am
the battery temp stays below 85 deg most of the time, never above 90 deg.
Ouch

If you can improve (decrease) the average battery temp it will last longer.
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

jmurtagh13
Posts: 25
Joined: Sun Nov 01, 2015 4:54 am
Delivery Date: 10 Mar 2018
Leaf Number: 300844
Location: Atlanta GA

Re: The 40KWH Battery Topic

Fri Sep 11, 2020 3:04 pm

DougWantsALeaf wrote:
Fri Sep 11, 2020 11:26 am
Nice graph. Have your miles been put on fairly consistently over the past 2 1/2 years?
Thanks.

Yes for the most part, this last month was a rare exception, we put on an additional 300 miles to our normal 700 a month.
2018 Leaf March 10, 2018
32 months, 23,543 miles
SOH 89.59

jmurtagh13
Posts: 25
Joined: Sun Nov 01, 2015 4:54 am
Delivery Date: 10 Mar 2018
Leaf Number: 300844
Location: Atlanta GA

Re: The 40KWH Battery Topic

Fri Sep 11, 2020 3:17 pm

SageBrush wrote:
Fri Sep 11, 2020 11:59 am
jmurtagh13 wrote:
Fri Sep 11, 2020 11:04 am
the battery temp stays below 85 deg most of the time, never above 90 deg.
Ouch

If you can improve (decrease) the average battery temp it will last longer.
That would be hard to do in Atlanta's summers. By the time the charging starts about 3:00am the battery is down to between 75 and 80. and that is just during the hottest 4 months of the year. The other 8 months it's 70 or below. I really thought that those temperatures were reasonable. My understanding is that EV's with battery thermal management don't start cooling until the batteries reach around 110 degrees.
2018 Leaf March 10, 2018
32 months, 23,543 miles
SOH 89.59

SageBrush
Posts: 5375
Joined: Sun Mar 06, 2011 2:28 am
Delivery Date: 13 Feb 2017
Location: NM

Re: The 40KWH Battery Topic

Fri Sep 11, 2020 3:27 pm

jmurtagh13 wrote:
Fri Sep 11, 2020 3:17 pm
SageBrush wrote:
Fri Sep 11, 2020 11:59 am
jmurtagh13 wrote:
Fri Sep 11, 2020 11:04 am
the battery temp stays below 85 deg most of the time, never above 90 deg.
Ouch

If you can improve (decrease) the average battery temp it will last longer.
That would be hard to do in Atlanta's summers. By the time the charging starts about 3:00am the battery is down to between 75 and 80. and that is just during the hottest 4 months of the year. The other 8 months it's 70 or below. I really thought that those temperatures were reasonable. My understanding is that EV's with battery thermal management don't start cooling until the batteries reach around 110 degrees.
Reasonable for driving -- sure.
Reasonable for degradation -- No

I can only speak about my Tesla -- temp management is waay lower than 110F. You can watch youtube videos by Bjorn Nyland when he monitors pack temps after supercharging. IIRC the battery is cooled down into the 80s F immediately after DC charging but the car is still being driven, and once the car is parked the battery is cooled into the 70s F within an hour or two. That is the pack chemistry of the Model 3, which I gather prefers life at a warmer temperature than prior Tesla cell chemistries.

If you keep the car in a poorly ventilated garage, consider instead leaving it outside during the hot months when ambient is less than your garage. You are otherwise managing the car wisely, but battery temp is THE issue with these cars. The more you can do for the LEAF battery, the longer it lasts. My 2013 LEAF still has 11.5 battery capacity bars but I start fretting when the temp bars goes over 5. That is unfortunately what it takes to get long(er) life from these cars.
Last edited by SageBrush on Fri Sep 11, 2020 4:20 pm, edited 4 times in total.
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

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