The 40KWH Battery Topic

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DaveinOlyWA said:
danrjones said:
LeftieBiker said:
I leased mine about 3 days before Dan, and my odometer reads 3,503, IIRC.
Click to expand...

Death by a thousand paper cuts?

My in town isn't large enough to exceed about 20 miles a day. And my actual commute is about 2.5 each way. Even if the battery heavily degrades in the heat the car will do fine in town for years. Mileage might be irrelevant to degradation ...
Click to expand...

What is your SOC targets for charge/discharge? What "seems" to be common are LEAFs driven heavily that degrade slowly while other LEAFs driven very lightly degrade faster. On the latter, there was a lot of evidence suggesting the lack of custom charge settings being the a factor with more than a handful simply "plugging it in and forgetting it"

My 30 kwh LEAF with supposedly one of the worst batteries went 30,000 miles in 14 months and 2 days died with 100% SOH and ahr of 82.05 of max 82.34 or 99.6% of new capacity. Since I rarely charged to full, I don't know how close I was to the maximum GID count of 363 but guessing I wasn't too far off. I did 116 miles on a single charge in Jan 2 days before the accident
Click to expand...

Well if only Nissan allowed a set point for SOC, right?

But most of the time I have my timer set to well after I leave for work, so that when I unplug I'm around 70-75%. It is never the same each time for some odd reason but close enough. And I'll recharge when I get down around 35%. Sometimes 40% if a weekend is coming so I don't have to charge on the weekend, because inevitably I'll plugin and forget about it Saturday or Sunday morning and it would charge to full.

I'm still a believer that part of my problem is the heat here. I don't buy the idea heat has no impact. For one thing, even the BMS treats hot weather differently. During the winter that daily adjustment of 0.01 occurs only once a week, or even less. Right now I'm loosing 0.01 every day, yesterday morning it dropped 0.02. I think we all agree the BMS appears artificial. But even if the computer is artificially lowering my SOH faster during hot weather, then it means Nissan engineers programmed it to take away more during hot weather. Why would they do that? The most obvious reason is because hot weather degrades the battery faster. You are welcome to disagree but the fact remains the BMS takes away more during hot weather. That's a fact for my 2018. Now hopefully that will stop... but it hasn't yet. Last three month adjustment was basically nil so I'm curious to see what happens after the summer.
 
I agree with you that heat, especially consistent heat still matters. I don't know if the couple hours around a fast charge hurts too bad (30 to charge and few hours to dissipate), but having the battery sit at 90-100F for weeks can't help things.

It doesn't seem like with the new batteries that the cold arrests things the way it did with the earlier car. My 2013 would consistently lost about 5-10 GID charging capability as we went into winter and then get 7-8 GID back as spring warmed the car back up. I didn't that drift this winter with the car in either direction.

In terms of the daily decline, in the past 36 days, my SV+ (purchased early June 2019) has lost .14, which is a bit faster than what I saw between November and March. Between Feb 15 and April 2nd (so 45 days) I lost .06 for comparison. I feel like the daily changes are likely more real than the quarterly battery buffering.

Now the car (SV+) still shows 260 miles on a full charge, based on 2/3rds local driving. I can see gids charged are not as many as when the car was new, but the GOM hasn't taken as big of a hit for similar driving patterns. I can't quite explain that one.

I can't explain JerryAZ as to how his car has held up so well. Let's see what my 2 car's next adjustment cycle brings in late July (S+) and late August (SV+).
 
danrjones said:
I'm still a believer that part of my problem is the heat here. I don't buy the idea heat has no impact. For one thing, even the BMS treats hot weather differently. During the winter that daily adjustment of 0.01 occurs only once a week, or even less. Right now I'm loosing 0.01 every day, yesterday morning it dropped 0.02. I think we all agree the BMS appears artificial. But even if the computer is artificially lowering my SOH faster during hot weather, then it means Nissan engineers programmed it to take away more during hot weather. Why would they do that? The most obvious reason is because hot weather degrades the battery faster. You are welcome to disagree but the fact remains the BMS takes away more during hot weather. That's a fact for my 2018. Now hopefully that will stop... but it hasn't yet. Last three month adjustment was basically nil so I'm curious to see what happens after the summer.
Click to expand...

Your comments are spot on! To think otherwise is naive.
 
DougWantsALeaf said:
I saw a YouTube today from Portugal about the ID3, and in some of the leaked documents, VW mentioned that ambient temperature affects battery life.
Click to expand...

I saw a hot hatch somewhere on the WWW over the weekend, does VW have a sub brand called "SEAT"? If you like hatchbacks, check it out, i thought it looked even better than the ID3 and it will be built on the same platform I believe. Anyway I thought it looked sharp. YMMV

So the question is, HOW does ambient impact life. And do they mean SOC or SOH?

I need to update my excel plots with all my latest data. Was at 89.65% SOH this AM. But my HX is dropping, 108.48. I wish it was easier to post charts and graphs here but I can't post directly.

Added note: The trend-line in excel, which of course could drastically change, suggests I'll loose my first bar around Feb to March of next year (SOH drop below 85%?)
 
danrjones said:
So the question is, HOW does ambient impact life.
Click to expand...

You know the answer to that, i.e. it depends on the temp of ambient, right? If you live in Death Valley during the summer, it really matters.
If you live in the PNW, ambient typically is of little concern.

danrjones said:
But my HX is dropping, 108.48.
Click to expand...

Why worry about HX, with the Leaf2 it's meaningless? The only parameters worth tracking are SOH & Ahr, Ahr being key.
Since the Li Ion battery voltage doesn't change significantly over SOC, one's range is best described by miles/Ahr.
 
I think Seat is a VW model line, not a brand but someone in the EU should know for sure.

As far as ambient temp affects, I always thought was related to Arrhenius' Law, which I've taken to hold that atomic/chemical reactions (degradation) happen faster at warmer temperatures.
 
goldbrick said:
I think Seat is a VW model line, not a brand but someone in the EU should know for sure.
Click to expand...
It is a brand of VAG:
https://www.volkswagenag.com/en/group.html
https://www.volkswagenag.com/en/brands-and-models/seat.html
https://www.seat.com/
https://www.seat.com/company/history.html
 
lorenfb said:
danrjones said:
So the question is, HOW does ambient impact life.
Click to expand...

You know the answer to that, i.e. it depends on the temp of ambient, right? If you live in Death Valley during the summer, it really matters.
If you live in the PNW, ambient typically is of little concern.

danrjones said:
But my HX is dropping, 108.48.
Click to expand...

Why worry about HX, with the Leaf2 it's meaningless? The only parameters worth tracking are SOH & Ahr, Ahr being key.
Since the Li Ion battery voltage doesn't change significantly over SOC, one's range is best described by miles/Ahr.
Click to expand...

I DO practically live in Death Valley. But the warranty of my Leaf didn't say I couldn't.
 
danrjones said:
DaveinOlyWA said:
danrjones said:
Death by a thousand paper cuts?

My in town isn't large enough to exceed about 20 miles a day. And my actual commute is about 2.5 each way. Even if the battery heavily degrades in the heat the car will do fine in town for years. Mileage might be irrelevant to degradation ...
Click to expand...

What is your SOC targets for charge/discharge? What "seems" to be common are LEAFs driven heavily that degrade slowly while other LEAFs driven very lightly degrade faster. On the latter, there was a lot of evidence suggesting the lack of custom charge settings being the a factor with more than a handful simply "plugging it in and forgetting it"

My 30 kwh LEAF with supposedly one of the worst batteries went 30,000 miles in 14 months and 2 days died with 100% SOH and ahr of 82.05 of max 82.34 or 99.6% of new capacity. Since I rarely charged to full, I don't know how close I was to the maximum GID count of 363 but guessing I wasn't too far off. I did 116 miles on a single charge in Jan 2 days before the accident
Click to expand...

Well if only Nissan allowed a set point for SOC, right?

But most of the time I have my timer set to well after I leave for work, so that when I unplug I'm around 70-75%. It is never the same each time for some odd reason but close enough. And I'll recharge when I get down around 35%. Sometimes 40% if a weekend is coming so I don't have to charge on the weekend, because inevitably I'll plugin and forget about it Saturday or Sunday morning and it would charge to full.

I'm still a believer that part of my problem is the heat here. I don't buy the idea heat has no impact. For one thing, even the BMS treats hot weather differently. During the winter that daily adjustment of 0.01 occurs only once a week, or even less. Right now I'm loosing 0.01 every day, yesterday morning it dropped 0.02. I think we all agree the BMS appears artificial. But even if the computer is artificially lowering my SOH faster during hot weather, then it means Nissan engineers programmed it to take away more during hot weather. Why would they do that? The most obvious reason is because hot weather degrades the battery faster. You are welcome to disagree but the fact remains the BMS takes away more during hot weather. That's a fact for my 2018. Now hopefully that will stop... but it hasn't yet. Last three month adjustment was basically nil so I'm curious to see what happens after the summer.
Click to expand...

That is a good plan. I have seen a few studies that suggest the best shallow cycle range is actually a bit more than 50% so my "target" is 60% but I have a slightly shorter commute than what I normally replace on a daily basis so the SOC creeps up during the week so I end up anywhere from 55% early in the week to 70% towards the end.

I set mine to start charging at 4 AM and get up at 5:40, leaving at 7. So if I know the SOC will be high, I unplug when I get up or soon after. If its normal, I usually unplug around 6:30ish. If I plan to take a longer (much longer) detour that day, I will leave it plugged in until I depart.

Realize, I use barely 10% of my range on a straight to work, straight home commute (there are detours I commonly make but none add more than 2-3 miles to the distance traveled)

So right now, slightly more than half of my cycling is in the 50sih to 65% range. Generally if I get home with more than 50% I will sometimes skip a day
 
No updates in this thread for awhile, I guess everyone has those "+" models now!

Stats as of this AM, the summer keeps chipping away at my SOH.

SOH: 89.45%
AMPHr: 103.26
Hx: 108.43
Mileage: ~ 6800 miles

IF, and that's a big IF, I have any more of those 3 month adjustments the next one would be around Sept 18th.
But not sure I will have any more of those as my last one in June was basically nothing.
The summer definitely seems to impact the battery, or the BMS, as I am loosing .01 or even .02 SOH each day.
 
Even us Plus owners see similar activity. My S+ is down .3 over the past 2 months (now 98.2%), and my SV+ is down .36 since mid may (94.29%). Both cars are up for their quarterly updates in about a week.
 
Arw68mDl.png


21,050 Miles and 29 Months.

Experienced a large negative update the previous month of -1.13%. This last month the loss was -0.14 which is higher than many of the last monthly losses for the last year. Heat seems to be a big factor. It has been hotter here in Atlanta this summer. Also the car now sits outside in my driveway during the day versus a cooler underground parking garage. This started at beginning of March when I started working from home. My guess is the BMS does a battery health check about every three months, makes an adjustment if necessary, then sets the new calculated rate of loss for the next three months based on the new health number and actual rate of loss for the previous three months. That new rate will likely vary based on other parameters like charging cycles, types of charges and temperature. Anyway that's my theory.
 
jmurtagh13 said:
Arw68mDl.png


21,050 Miles and 29 Months.

Experienced a large negative update the previous month of -1.13%. This last month the loss was -0.14 which is higher than many of the last monthly losses for the last year. Heat seems to be a big factor. It has been hotter here in Atlanta this summer. Also the car now sits outside in my driveway during the day versus a cooler underground parking garage. This started at beginning of March when I started working from home. My guess is the BMS does a battery health check about every three months, makes an adjustment if necessary, then sets the new calculated rate of loss for the next three months based on the new health number and actual rate of loss for the previous three months. That new rate will likely vary based on other parameters like charging cycles, types of charges and temperature. Anyway that's my theory.
Click to expand...

You are 9 of 15 over 2 years that is in the "90's" and I mean between 90.00 and 90.99% SOH. Being in Atlanta, you are simply another example of heat not being an extreme factor. Looking like time and likely average SOC is the key factors. I know a guy in WA who got his about the same time as you. Has nearly 60,000 miles and his last report he was like 90.77% SOH.

The other 5? Well, two are in GB and are still 93 and 94% SOH. One in Canada at 94% and then two one at 86%, the other at 88%.
 
DaveinOlyWA said:
I mean between 90.00 and 90.99% SOH.
Click to expand...
Funny. Give him a month.

I doubt that Nissan has changed its stripes: the warranty is tightly bound to expected battery degradation of the fleet. When the battery warranty was changed from 5 years to 8 years it implied a fleet improvement in annual degradation from ~ 6% a year to 4%. I doubt this is heat tolerant chemistry and it sure isn't improved cooling so perhaps it is less DCFC as the battery size grows, and less swings into really high battery temperatures.
 
2019 40kWh Leaf SV
Purchased Jun 2019
Mfg: Mar 2019

6/8/19:
AHr= 114.24
SOH= 98.96%
Hx= 97.66%
Odo= 15 mi
QC= 4
L1/L2= 2

8/3/19:
AHr= 113.21
SOH= 98.07%
Hx= 106.56%
Odo= 986 mi
QC= 4
L1/L2= 21

8/10/20:
AHr= 107.53
SOH= 93.15%
Hx= 102.43%
Odo= 7,922 mi
QC= 22
L1/L2= 147

We've been much more careful with this Leaf. No L1, L2, or DC fast charging at high battery temps, avoiding charging at home with high ambient temperatures, and avoiding leaving battery sitting charged at high SOC. No road tripping. Only use DCFC at local stations after the vehicle has been idle since the prior day.

Wife treated the prior 30 kWh Leaf more often without kid gloves, more often just plug and drive as convenient. That didn't go too well for that battery.
 
iPlug said:
Only use DCFC at local stations after the vehicle has been idle since the prior day.
Click to expand...
Do you mean DCFC before the drive of the day ? What is the car battery temp after the charge and drive ?
Since it is only a local car I'm not sure why DC fast charging is needed. It sure seems like something to avoid in the summer if possible.

At our home, we set the LEAF to finish charging at 6:30 am during the summer. That way the charging is during the cool(er) early AM hours.
 
SageBrush said:
iPlug said:
Only use DCFC at local stations after the vehicle has been idle since the prior day.
Click to expand...
Do you mean DCFC before the drive of the day ? What is the car battery temp after the charge and drive ?
Click to expand...
It's only been used as a local car, wife's - who is still too nervous to take it out of home charging range by herself. She's gone as far as 100-150 miles round trip a couple times and panicked because issues with DCFC and L2 being down or occupied when she got there.

The reason we even do DCFC is because we have 2 years "no-charge-to-charge". So just getting free electricity in the morning when the wife goes out for local errands at an EVGO station.

Have not checked the battery temps after DCFC. On our 40 kWh Leaf there don't seem to be discrete bars like our prior 30 kWh Leaf. On the few times I have looked, the battery was not in the red zone.

The vehicle is cold soaked overnight and only driving a few miles until the DCFC for local shopping then probably only <30 miles driven on it the rest of the day. She also does not charge up to 100% SOC with DCFC.


SageBrush said:
Since it is only a local car I'm not sure why DC fast charging is needed. It sure seems like something to avoid in the summer if possible.
Click to expand...
Yes but free. :D
If we owned the vehicle instead of leased again (3 year), and knowing the Leaf battery history, yeah would likely avoid that entirely.

SageBrush said:
At our home, we set the LEAF to finish charging at 6:30 am during the summer. That way the charging is during the cool(er) early AM hours.
Click to expand...
Similar here. Temps in our garage coolest just before sunrise. She usually plugs it in ~7 am in the summer to charge up a couple hours.
 

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