The 40KWH Battery Topic

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DaveinOlyWA said:
In the previous 3 LEAFs, I saw the opposite where it maintained "new" status for probably (don't have specific stats on the 2011) the first 6 months or more. The 2016 went 14 months and over 29,000 miles at 100% SOH and 99.64% of its original ahr

Yes, but you do many QCs, which increase the estimated SOH.
 
Ok, got the new SOH, its 95.64, 0.07 lower, than 8 hours before... either the BMS is dead, or the battery cells are dead. Since I have issues with epedal regen also, I think the BMS is buggy somewhere. Now I need to wait until it dies so I get a replacement...
 
kovadam said:
Ok, got the new SOH, its 95.64, 0.07 lower, than 8 hours before... either the BMS is dead, or the battery cells are dead. Since I have issues with epedal regen also, I think the BMS is buggy somewhere. Now I need to wait until it dies so I get a replacement...

Past capacity estimates have been about +-3% or worse accuracy. 1% isn't meaningful. 0.1% is even less meaningful.
 
kovadam said:
Now I am at 95.22. Basically every time I turn off the car, then on it goes down by 0.07%...

Which doesn't mean that capacity has decreased by 0.07%.

An estimation isn't the same as the real thing.
 
kovadam said:
Yeah, thats right. Will see if the drop stops,and will also see if the next time I charge to 100%, how many GIDs and kWh I get....

GIDs are also estimated. As are kWh as reported by the car.

Discharge to 20% or so, and do a measured charge test with a metered EVSE. Do it with the same battery temperature each time.
 
kovadam said:
Ok, got the new SOH, its 95.64, 0.07 lower, than 8 hours before
You can't make meaningful comparisons of SOH changes unless you do so over the order of months. Trying to compare changes to the value over hours is just noise.
 
jlv said:
kovadam said:
Ok, got the new SOH, its 95.64, 0.07 lower, than 8 hours before
You can't make meaningful comparisons of SOH changes unless you do so over the order of months. Trying to compare changes to the value over hours is just noise.

I made the comparison over months, this is why it was very-very strange, that it dropped 1.5% within a few days, and about 0.7% within hours, since from the beginning it was declining quite slowly and reached 2.5% drop in 6 months, then 1.5% drop in just 3 days...
 
WetEV said:
DaveinOlyWA said:
In the previous 3 LEAFs, I saw the opposite where it maintained "new" status for probably (don't have specific stats on the 2011) the first 6 months or more. The 2016 went 14 months and over 29,000 miles at 100% SOH and 99.64% of its original ahr

Yes, but you do many QCs, which increase the estimated SOH.

Several experiments have shown usage and not method of charging has the greatest effect. Realize NCTC for me lasted only 90 days on my 2013 so it was charged at home on level 2 about 90% of the time. It did the same; had like new stats for first 8 months and 10,500 miles
 
DaveinOlyWA said:
WetEV said:
DaveinOlyWA said:
In the previous 3 LEAFs, I saw the opposite where it maintained "new" status for probably (don't have specific stats on the 2011) the first 6 months or more. The 2016 went 14 months and over 29,000 miles at 100% SOH and 99.64% of its original ahr

Yes, but you do many QCs, which increase the estimated SOH.

Several experiments have shown usage and not method of charging has the greatest effect. Realize NCTC for me lasted only 90 days on my 2013 so it was charged at home on level 2 about 90% of the time. It did the same; had like new stats for first 8 months and 10,500 miles

For the newer folks following along, what is NCTC?
 
DaveinOlyWA said:
WetEV said:
DaveinOlyWA said:
In the previous 3 LEAFs, I saw the opposite where it maintained "new" status for probably (don't have specific stats on the 2011) the first 6 months or more. The 2016 went 14 months and over 29,000 miles at 100% SOH and 99.64% of its original ahr

Yes, but you do many QCs, which increase the estimated SOH.

Several experiments have shown usage and not method of charging has the greatest effect. Realize NCTC for me lasted only 90 days on my 2013 so it was charged at home on level 2 about 90% of the time. It did the same; had like new stats for first 8 months and 10,500 miles

This is complex, and I agree that usage plays a large factor as well. Also does battery temperature, not just for actual capacity (lower at low temperatures, maximum at some temperature around 25 C, lower at higher temperatures), and capacity loss (a longer time needed) but also temperature and temperature change impacts capacity estimates. Several experiments doesn't cover the complexity.

I look at the 97.35% (or whatever) readout from LeafSpy and remember that true State Of Health could be anywhere between 94% and 100%.

I've found ways to force the capacity estimate up and down. I don't have any reason to think this changes actual capacity.
 
goldbrick said:
NCTC = no charge ($) to charge. I think it was promotion from Nissan that allowed free public charging for a period of time.

They are still doing it. Free DCQC charging sessions for two years (with restrictions). I have yet to pay a penny for a QC session.
 
danrjones said:
DaveinOlyWA said:
WetEV said:
Yes, but you do many QCs, which increase the estimated SOH.

Several experiments have shown usage and not method of charging has the greatest effect. Realize NCTC for me lasted only 90 days on my 2013 so it was charged at home on level 2 about 90% of the time. It did the same; had like new stats for first 8 months and 10,500 miles

For the newer folks following along, what is NCTC?

Program of free access to Blink, Webasto and EVGO for 30 min QC sessions that lasts 2 years from delivery date of your new LEAF.
 
I purchased a 40 kWh SV on 4/30. The car was built in February 2019. I've put about 700 miles on it since 4/30, and I just did my first Leaf Spy reading on 5/15. I have a screen shot of the reading, but I'm not sure how to post it. Anyway, here are the most relevant stats:

AHr: 114.9

SOH: 99.35%

Hx: 101.31%

GIDS: 196

SOC: 38.8% (the dash SOC says 30%)

kWh Remain: 15.2

1 QC, 37 L1/L2 (this QC must have been done by the dealership because I've never done one. And I've also only L2 charged it 16 times, and L1 charged 0 times, so the dealership must have L1 or L2 charged it the other 21 times. Kind of a lot of charging events for a car that only had 7 miles on it when I bought it).

A few questions:

1. That SOC reading - is that of the usable or the nominal capacity? 15.2 kWh remaining/.388% SOC = 39.175 kWh of actual capacity. So is that what I have? If SOH is actual capacity/40, then my SOH should really be 97.9%. If SOH is actual capacity/38.5 (the alleged true usable capacity of the 40 kWH Leaf), then my SOH would really be 101.75%. On the other hand, if my car currently has 39.175 kWh of capacity, and it has an SOH of 99.35%, then it should have started with 39.43 kWh. So I'm obviously missing something about the math here...

2. The discrepancy between that SOC reading and the Leaf's dash SOC is 8.8%. This must be the roughly 10% that the Leaf BMS software hides from you. But that 8.8% hidden amount is of what original number? 40 kWh? 38.5 kWh? This is another way of asking: how many kWh does Leaf Spy say I have, and how many kWh does Nissan say I have?
 
Kieran973 said:
1 QC, 37 L1/L2 (this QC must have been done by the dealership because I've never done one. And I've also only L2 charged it 16 times, and L1 charged 0 times, so the dealership must have L1 or L2 charged it the other 21 times. Kind of a lot of charging events for a car that only had 7 miles on it when I bought it).

Do you have a timer set? If so, then every plug in followed by a charge later generates 2 L1/l2 charge events.

1. That SOC reading - is that of the usable or the nominal capacity? 15.2 kWh remaining/.388% SOC = 39.175 kWh of actual capacity. So is that what I have? If SOH is actual capacity/40, then my SOH should really be 97.9%. If SOH is actual capacity/38.5 (the alleged true usable capacity of the 40 kWH Leaf), then my SOH would really be 101.75%. On the other hand, if my car currently has 39.175 kWh of capacity, and it has an SOH of 99.35%, then it should have started with 39.43 kWh. So I'm obviously missing something about the math here...

SOC in LeafSpy is nominal. The dash is usable capacity (with an extra buffer at the bottom for some model years).

kWh in LeafSpy is an undocumented internal value in the BMS multiplied by a fudge factor that seems about correct. Don't get your hopes too high. It does seem to be mostly correct, but getting math to work out to better than +/- 3% isn't realistic.

2. The discrepancy between that SOC reading and the Leaf's dash SOC is 8.8%. This must be the roughly 10% that the Leaf BMS software hides from you. But that 8.8% hidden amount is of what original number? 40 kWh? 38.5 kWh? This is another way of asking: how many kWh does Leaf Spy say I have, and how many kWh does Nissan say I have?

The difference between the BMS SOC and the dash SOC will vary with charge level. There is a top and a bottom buffer. At a full charge, the BMS will say something like 93% and the dash will say 100%. The dash percentage will go down faster, at 10% dash SOC the BMS SOC will be around 20%.
 
Kieran973 said:
1 QC, 37 L1/L2 (this QC must have been done by the dealership because I've never done one. And I've also only L2 charged it 16 times, and L1 charged 0 times, so the dealership must have L1 or L2 charged it the other 21 times. Kind of a lot of charging events for a car that only had 7 miles on it when I bought it).

The 2018 40kwH I bought also shows 1 QC & only had 3 miles on the odometer before my initial test drive and the dealer didn't have a working CHademo charge station so I'm confident that the car is QC'd at the factory as part of QA testing as well as providing the hopefully correct SOC for transport and storage before being purchased.

L2 charging seems painfully slow in the context of an factory assembly rate of production timeline.
 
Kieran973 said:
I purchased a 40 kWh SV on 4/30. The car was built in February 2019. I've put about 700 miles on it since 4/30, and I just did my first Leaf Spy reading on 5/15. I have a screen shot of the reading, but I'm not sure how to post it. Anyway, here are the most relevant stats:

AHr: 114.9

SOH: 99.35%

Hx: 101.31%

GIDS: 196

SOC: 38.8% (the dash SOC says 30%)

kWh Remain: 15.2

1 QC, 37 L1/L2 (this QC must have been done by the dealership because I've never done one. And I've also only L2 charged it 16 times, and L1 charged 0 times, so the dealership must have L1 or L2 charged it the other 21 times. Kind of a lot of charging events for a car that only had 7 miles on it when I bought it).

A few questions:

1. That SOC reading - is that of the usable or the nominal capacity? 15.2 kWh remaining/.388% SOC = 39.175 kWh of actual capacity. So is that what I have? If SOH is actual capacity/40, then my SOH should really be 97.9%. If SOH is actual capacity/38.5 (the alleged true usable capacity of the 40 kWH Leaf), then my SOH would really be 101.75%. On the other hand, if my car currently has 39.175 kWh of capacity, and it has an SOH of 99.35%, then it should have started with 39.43 kWh. So I'm obviously missing something about the math here...

2. The discrepancy between that SOC reading and the Leaf's dash SOC is 8.8%. This must be the roughly 10% that the Leaf BMS software hides from you. But that 8.8% hidden amount is of what original number? 40 kWh? 38.5 kWh? This is another way of asking: how many kWh does Leaf Spy say I have, and how many kWh does Nissan say I have?


1) It is the capacity and the usable portion is dependent upon cell balance. Generally you can use all but roughly .4 to .7 kwh. I have only Turtled my LEAF once and that was .6 kwh remaining. Not that it makes a difference but I have done VERY little top end balancing (15 months ownership with less than 20 full charges)

The LS SOC reading is the "real" SOC which means its range is NOT zero to 100% like the dash since that would be near instant death of your pack. So usable range again is based on your cell balance but it should be no higher than 98% normally or lower than 1-2%. My lowest was 1.7 % (see above)

SOH is a bit arbitrary and has nothing to do with capacity. You also need to understand the difference between what you can see and what you can use. In the grand scheme of things, SOH can be used as a guide to determine pack capacity loss but it is subject to random variables including charging/driving habits.


2) The discrepancy between the dash and LEAF Spy is a moving target. Nissan doesn't say how many kwh you have and they have NEVER reported it. Now realize some EV manufacturers (Kia) only report useable capacity of the packs. Nissan only reports actual capacity of the pack.

This might give you some insight.

https://daveinolywa.blogspot.com/2019/05/april-2019-drive-report-now-that-my.html
 
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