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Re: The 40KWH Battery Topic

Posted: Sat Sep 12, 2020 8:52 am
by lorenfb
DaveinOlyWA wrote:
Sat Sep 12, 2020 8:47 am
lorenfb wrote:
Sat Sep 12, 2020 8:18 am
DaveinOlyWA wrote:
Fri Sep 11, 2020 7:39 pm


Interesting theory but there are a handful that would seem to counter that. The 40 likely to lose the first bar is only in the high 90's. Not sure what Hx history was previously. He has piled on the miles quite rapidly though. IIRC, he is averaging well over 20,000 miles a year
And your references for this statement are?
His LEAF Spy screenshot on Facebook
Some of us don't waste time with Facebook, so provide the actual data you're referring to.

Re: The 40KWH Battery Topic

Posted: Sun Sep 13, 2020 9:34 am
by jmurtagh13
cwerdna wrote:
Fri Sep 11, 2020 5:49 pm
jmurtagh13 wrote:
Fri Sep 11, 2020 5:31 pm
Also my understanding is that charging at a high temperature does the most damage.
I don't think that's correct at all. I pointed to https://www.nec.com/en/global/techrep/j ... 120112.pdf when I was trying to educate Powersurge at viewtopic.php?p=508974#p508974. Page 3, section 3.1 makes no mention of charging.

Table 3 at https://batteryuniversity.com/learn/art ... _batteries talks about capacity remaining after storage at 40% vs 100% SoC at various temps. Ditto for table 2 of https://batteryuniversity.com/learn/art ... _batteries.

See my examples at https://www.mynissanleaf.com/viewtopic. ... 69#p496269. https://www.mynissanleaf.com/viewtopic. ... 95#p473995 is in Phoenix and has the same build month as me. I'm still at 11 bars now with SOH around 79.xx% in a hotter part of the SF Bay Area. That guy lost his 4th bar (at 8 bars) in late 2016.

L2 charging does heat the battery by a few degrees F, so yeah, it's better to start off charging when it's cooler so that the battery doesn't get as hot. DC FCing can really heat up the battery, esp. multiple ones in a day.

https://web.archive.org/web/20170717073 ... hp?t=22134 got his 30 kWh Leaf to a battery temp of 137 F.
Thanks for the links. I am familiar and a fan of batteryuniversity. After doing some more research (it's been awhile) it does appear that charging in it self, the chemical reaction does not significantly impact battery life at higher temperatures. The main damage, as you indicated is the rising of the battery temperature at the faster charge rates and then the battery now at a high charge level and a higher temperature that is responsible for the largest impact on battery life if left at those higher levels. So even if the TMS is letting the battery temperature rise during the charging cycle, but then bring the temperature back down afterwards, the battery is receiving a major benefit in being cool for the majority of its life, assuming the TMS is allowed to function frequently enough. What I still struggle with is why high mileage Leafs in the same climate seem to be at the same SOH at low mileage Leafs. Charge / run cycles do heat up the battery, so you would think that higher mileage Leafs would degrade faster. Also higher mileage Leafs owners would likely be charging their batteries to a high charge level.

Re: The 40KWH Battery Topic

Posted: Sun Sep 13, 2020 10:13 am
by lorenfb
jmurtagh13 wrote:
Sun Sep 13, 2020 9:34 am
cwerdna wrote:
Fri Sep 11, 2020 5:49 pm
jmurtagh13 wrote:
Fri Sep 11, 2020 5:31 pm
Also my understanding is that charging at a high temperature does the most damage.
I don't think that's correct at all. I pointed to https://www.nec.com/en/global/techrep/j ... 120112.pdf when I was trying to educate Powersurge at viewtopic.php?p=508974#p508974. Page 3, section 3.1 makes no mention of charging.

Table 3 at https://batteryuniversity.com/learn/art ... _batteries talks about capacity remaining after storage at 40% vs 100% SoC at various temps. Ditto for table 2 of https://batteryuniversity.com/learn/art ... _batteries.

See my examples at https://www.mynissanleaf.com/viewtopic. ... 69#p496269. https://www.mynissanleaf.com/viewtopic. ... 95#p473995 is in Phoenix and has the same build month as me. I'm still at 11 bars now with SOH around 79.xx% in a hotter part of the SF Bay Area. That guy lost his 4th bar (at 8 bars) in late 2016.

L2 charging does heat the battery by a few degrees F, so yeah, it's better to start off charging when it's cooler so that the battery doesn't get as hot. DC FCing can really heat up the battery, esp. multiple ones in a day.

https://web.archive.org/web/20170717073 ... hp?t=22134 got his 30 kWh Leaf to a battery temp of 137 F.
Thanks for the links. I am familiar and a fan of batteryuniversity. After doing some more research (it's been awhile) it does appear that charging in it self, the chemical reaction does not significantly impact battery life at higher temperatures. The main damage, as you indicated is the rising of the battery temperature at the faster charge rates and then the battery now at a high charge level and a higher temperature that is responsible for the largest impact on battery life if left at those higher levels. So even if the TMS is letting the battery temperature rise during the charging cycle, but then bring the temperature back down afterwards, the battery is receiving a major benefit in being cool for the majority of its life, assuming the TMS is allowed to function frequently enough.
Right, that's the key!
jmurtagh13 wrote:
Sun Sep 13, 2020 9:34 am
What I still struggle with is why high mileage Leafs in the same climate seem to be at the same SOH at low mileage Leafs. Charge / run cycles do heat up the battery, so you would think that higher mileage Leafs would degrade faster. Also higher mileage Leafs owners would likely be charging their batteries to a high charge level.
You essentially answered your own question in your previous statement, i.e. without your last assumption.

Re: The 40KWH Battery Topic

Posted: Mon Sep 14, 2020 7:13 am
by danrjones
danrjones wrote:
Tue Sep 08, 2020 1:32 pm
My 2018 is in the middle of an adjustment.
Normally I try and get a leaf-spy reading every day for a few days leading up to the adjustment, but this time I was not able to do so, as I was out of town and my wife was using it. So my last reading was about 5-6 days before it started. I'm not going to put all my readings just the last two before the adjustment and the current two from yesterday and today. My guess would be that SOH was around 89.28. This is the first time my SOH has ever increased in either a 3 month adjustment or the daily adjustments.

Date | SOH | AMPhr | Hx

8/28/2020 89.31 103.10 108.18
8/31/2020 89.30 103.09 108.11
9/7/2020 89.46 103.27 107.97
9/8/2020 89.87 103.75 107.84

Whether you put faith in these numbers - or not - I know some like them reported. My pack finished its adjustment. Final numbers below.

Date | SOH | AMPhr | Hx
9/11/2020 90.21 104.14 107.61

Re: The 40KWH Battery Topic

Posted: Mon Sep 14, 2020 8:25 am
by DougWantsALeaf
Good news that it went up.

Re: The 40KWH Battery Topic

Posted: Tue Sep 15, 2020 7:06 pm
by DaveinOlyWA
danrjones wrote:
Mon Sep 14, 2020 7:13 am
danrjones wrote:
Tue Sep 08, 2020 1:32 pm
My 2018 is in the middle of an adjustment.
Normally I try and get a leaf-spy reading every day for a few days leading up to the adjustment, but this time I was not able to do so, as I was out of town and my wife was using it. So my last reading was about 5-6 days before it started. I'm not going to put all my readings just the last two before the adjustment and the current two from yesterday and today. My guess would be that SOH was around 89.28. This is the first time my SOH has ever increased in either a 3 month adjustment or the daily adjustments.

Date | SOH | AMPhr | Hx

8/28/2020 89.31 103.10 108.18
8/31/2020 89.30 103.09 108.11
9/7/2020 89.46 103.27 107.97
9/8/2020 89.87 103.75 107.84

Whether you put faith in these numbers - or not - I know some like them reported. My pack finished its adjustment. Final numbers below.

Date | SOH | AMPhr | Hx
9/11/2020 90.21 104.14 107.61
Up is good. In the last 3 months, I am guessing you drove less than normal?

Re: The 40KWH Battery Topic

Posted: Wed Sep 16, 2020 10:43 am
by danrjones
DaveinOlyWA wrote:
Tue Sep 15, 2020 7:06 pm
danrjones wrote:
Mon Sep 14, 2020 7:13 am
danrjones wrote:
Tue Sep 08, 2020 1:32 pm
My 2018 is in the middle of an adjustment.
Normally I try and get a leaf-spy reading every day for a few days leading up to the adjustment, but this time I was not able to do so, as I was out of town and my wife was using it. So my last reading was about 5-6 days before it started. I'm not going to put all my readings just the last two before the adjustment and the current two from yesterday and today. My guess would be that SOH was around 89.28. This is the first time my SOH has ever increased in either a 3 month adjustment or the daily adjustments.

Date | SOH | AMPhr | Hx

8/28/2020 89.31 103.10 108.18
8/31/2020 89.30 103.09 108.11
9/7/2020 89.46 103.27 107.97
9/8/2020 89.87 103.75 107.84

Whether you put faith in these numbers - or not - I know some like them reported. My pack finished its adjustment. Final numbers below.

Date | SOH | AMPhr | Hx
9/11/2020 90.21 104.14 107.61
Up is good. In the last 3 months, I am guessing you drove less than normal?
Actually, no, not really. Been working / driving to work pretty much the same.

So far mileage hasn't really seemed to be the "driving" factor in SOH for the Leaf's posted on here. Not sure what really is, assuming we can trust the leaf-spy readings. But my mileage has been pretty steady. My car is low mileage anyway, but my mileage has been steady. I think I'm at about 7300 miles but I'll have to check.

Re: The 40KWH Battery Topic

Posted: Wed Sep 16, 2020 8:18 pm
by DaveinOlyWA
danrjones wrote:
Wed Sep 16, 2020 10:43 am
DaveinOlyWA wrote:
Tue Sep 15, 2020 7:06 pm
danrjones wrote:
Mon Sep 14, 2020 7:13 am



Whether you put faith in these numbers - or not - I know some like them reported. My pack finished its adjustment. Final numbers below.

Date | SOH | AMPhr | Hx
9/11/2020 90.21 104.14 107.61
Up is good. In the last 3 months, I am guessing you drove less than normal?
Actually, no, not really. Been working / driving to work pretty much the same.

So far mileage hasn't really seemed to be the "driving" factor in SOH for the Leaf's posted on here. Not sure what really is, assuming we can trust the leaf-spy readings. But my mileage has been pretty steady. My car is low mileage anyway, but my mileage has been steady. I think I'm at about 7300 miles but I'll have to check.
What's not to trust in LEAF Spy? It only parrots what the car tells it.

In checking with others who had a boost;

Half said no change in driving. There is no seasonal correlation.

A few said they drove more because it was Summer.

Only one drove less and coincidentally, his increase was the smallest. I "think" it was .07% or something in that range. FYI; he only checks stats once a month so the increase could have been bigger and a .2% loss in a month is well within the normal range so it might have been near .3%. There were 2 others who claimed no change who also had increases in that range as well.

For reference; mine happened in Summer; July 2019 and it was during a period when I drove more than any quarter the previous year.

For the rest of the time I had the car, my drop between adjustments slowed way down and the October 2019 adjustment didn't happen at all.

Finally, miles do make very little difference as you mentioned. Considering the clockwork like 90 day adjustments (or 91 for those longer quarters) it should be no surprise that time is the factor. We have more than a 150% difference in mileage driven for cars picked up between Feb and Julyish of 2018 while most are now between 88 to 91% SOH.

Re: The 40KWH Battery Topic

Posted: Wed Sep 16, 2020 8:29 pm
by DougWantsALeaf
Dave, do you think miles plays much of a role at all in the algorithm for the daily or quarterly adjustments?

For the quarter (late May to late August) where we say our .6x% increase (on a 62 battery), our miles were fairly normal for the quarter, but up from the covid low driving spring.

Re: The 40KWH Battery Topic

Posted: Wed Sep 16, 2020 10:07 pm
by DaveinOlyWA
DougWantsALeaf wrote:
Wed Sep 16, 2020 8:29 pm
Dave, do you think miles plays much of a role at all in the algorithm for the daily or quarterly adjustments?

For the quarter (late May to late August) where we say our .6x% increase (on a 62 battery), our miles were fairly normal for the quarter, but up from the covid low driving spring.
Its hard to say. The reality is the pool of data is weak, inconsistent and filled with "it doesn't matter" evaluations that get written off as negligible. The result is people reporting what they think is important and that means we frequently see pertinent information left out.

What is pertinent? Good question but until we know more, we should be including it until it is proven its not important enough to track.

As time goes on, we should see groups of people diverging from the pack either outperforming the masses or underperforming.

I had hoped to have an active quarter but the smoke issue has me all but DOA. Doing anything outside is simply incredibly risky and the plans for some hikes before the end of Summer looks to be all but done. RIght now the projection has me finishing the quarter in the average range around 3600-3800 miles when I was on pace to be closer to 45-4700. I am just over 400 miles for this month which is well less than half of what I was mid month in July and August.