LeftieBiker
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Re: 2016-2017 model year 30 kWh bar losers and capacity losses

Sun Nov 12, 2017 3:33 am

And your speculation that charging just short of 100% is essentially harmless doesn't jibe with what is known about lithium batteries. With the optimal storage charge somewhere close to 20%, charging to 98% instead of 100% isn't likely to be the solution.
2013 "Brilliant Silver" SV with Premium Package and no QC, and 2009 Vectrix VX-1 with 18 Leaf cells.

The most offensive, tasteless phrase in use here is "Pulled the trigger." I no longer respond to posts that use it.

SageBrush
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Location: Colorado

Re: 2016-2017 model year 30 kWh bar losers and capacity losses

Sun Nov 12, 2017 6:01 am

lorenfb wrote:
SageBrush wrote:Judging from this LeafSpy photo, "100%" SoC in a LEAF is about 4.13 volts in a cell


Bottom line: Without fully characterizing (extensive analysis) the Leaf's cell, suggestions relating to charging are basically speculations.

I understand your point, which is why I am referencing cell voltages
2013 Model 'S' with QC & rear-view camera
Bought off-lease Jan 2017 from N. California with 63.9 Ahr after 22k miles
Car is now enjoying an easy life in Colorado

DaveinOlyWA
Gold Member
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Leaf Number: 314199
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Re: 2016-2017 model year 30 kWh bar losers and capacity losses

Sun Nov 12, 2017 7:23 am

GrowingTuna wrote:New poster (hey everyone!), but have been lurking for a while. Been really enjoying this thread, so feel obligated to add my data as additional fodder for research/discussion.

Picked up 2017 30 KWh Leaf on 07/2017. Live in SoCal (LA county). SOH was 100% when picked up. Stayed at 100% for about a month. Currently at 91% SOH, AHr 72.53, after 4 months of driving. Odometer reading at 3600. 80 QC, 99 L1/L2s. Many of those L1/L2s were done at the dealer (See below).

Needless to say, there is some pretty serious degradation already given the date of acquisition and mileage, but looks like this isn't an outlier. As has already been observed, age + mileage seem to be a secondary factor regarding degredation. This is a lease, so I'm not torn up over the fact.

Some interesting tidbits I've picked up thus far that may help the community:

1. The car was sitting on the lot for at least a few months before I leased it. When I picked up the car, it already had ~60 L1/L2 charges, with less than 200 miles on the odometer. I saw the dealer plug in the car after my 2 mile test drive (which started at full battery); I believe they always kept it at 100%. The car was not kept under shade at the dealer. Despite that, the car was at a very healthy 100% SOH and 80.6 AHr When I picked it up.

2. I follow the generally accepted guidelines for battery longevity -- as much as I can in the SoCal climate. Charging to ~80%, keeping battery above 20%, and (trying to) keep the battery as cool as possible. Most of my charging was to regain 25-50% of the battery. For the summer months, temp bars were almost always at 6; during the quick charges (which I kept <10 minutes), bars often hit 7 or 8. A couple of times I hit 9 temp bars, but immediately unplugged. Almost all QCs were done at night, where the car was best able to cool down. I have both a covered and uncovered parking space; I use both about equally. I periodically do L1 charges -- which never raise temp. Most of the charges I do are QC (I live right next to a free QC, so I can't resist!)

3. Battery degradation seemed to correspond to ambient temperature more than how I treated it. Despite periods of heavy QC, the periodic heat waves affected SOH and AHr much more severely. The past few weeks the AHr has remained almost at a standstill (changing by about +/-0.1), which aligns conveniently to the more temperate weather we have been blessed with as of late!

I've had leaf spy pro from the start, but there are a few holes in the data (bluetooth hasn't always been enabled to pick up data). Nonetheless, there are enough data points to garner some value. If anyone would like the leafspy data, please let me know and I'll provide!


Thanks for the input but not mentioning the dealership by name is CRIMINAL! They should be avoided at all costs! Your pack should have read 82.34 ahr. That 100% means nothing. I have LEAF over a year old with 26,000 miles on it with ahr as low as the mid 79's, Hx as low as 95.35% and still 100% SOH...

And yes heat is a killer but the worst is heat, high SOC and Time. Heat you can't change but the rest you can. Don't charge up unless you can do it quickly and drive immediately. IOW; you are better off to QC in the middle of noon day Sun if you are driving right away.

Lets play two scenarios; In both the parking lot temps are say 100º which should be typical for you. Both cars are at 30% SOC and you need a minimum of 70% to get home.

Scenario one; You have workplace charging and as luck would have it; you have a slot from 2 PM to 5 PM that covers the last 3 hours of your work day and its 6 KW level 2 charging. After the charge session is over, you have added a few degrees above ambient to your battery pack but it charges to 90%. This is one of the issues with workplace charging. In most cases, flexibility is not always a given.

Scenario two; you stop and QC a few miles away after work for 20 mins. Your pack finishes 15º above ambient and you charge to the same 90% SOC.


In Scenario one despite being a cooler charge, you still expose your car for a several hours at higher SOC. What is too high? Well, that is temp based and when its warm "some" level of degradation will happen all the time. So its a given that 60% is better than 70%, etc.

In Scenario two despite much hotter batteries, you exposure is now no more than what? Half the charge time plus maybe 20 mins of drive time and you are back below 70% SOC.

Get the picture? But that is only half the story. Its my (much disputed) claim that "hot" is no more than the 80's if the SOC is high enough. Again; how high is that? Good question but was unable to gather enough data to make anything other than a guess so if filling in very large gaps

100% SOC (per car or 97.7% SOC if you prefer) the significant start at 80º so best practice is use buffer. Don't do it over 70º Unless you plan to drive off immediately. For some; that may mean not charging to full at home all Summer long. How crazy is that?

Well, it is pretty crazy and for 6 months; that is EXACTLY WHAT I DID. and drove the car 26,100.2 miles in 365 days at the same time

Remember; the numbers provided are just guesses based on a very randomized data provided by this forum and others. so the "80º" or the "70º" has only casual comments to back it. Comments from here.
2011 SL; 44,598 miles. 2013 S; 44,840 miles.2016 S30 (build 10/2016)"low water marks" 26,100.2 miles.363GID Ahr 79.55Hx95.35%kwh28.1QCs227,L2's 237
My Blog; http://daveinolywa.blogspot.com" onclick="window.open(this.href);return false;

GrowingTuna
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Delivery Date: 30 May 2017

Re: 2016-2017 model year 30 kWh bar losers and capacity losses

Sun Nov 12, 2017 1:29 pm

And yes heat is a killer but the worst is heat, high SOC and Time. Heat you can't change but the rest you can. Don't charge up unless you can do it quickly and drive immediately. IOW; you are better off to QC in the middle of noon day Sun if you are driving right away.


Of course, but if I'm only QC to 80%, would this be such a cause for concern? It's my understanding that the damage from high SOC comes when you are charging the battery to full or nearly so. Heat compounds the damage, as well as time sitting at such a high charge. If leaving my car at 80% charge overnight is a concern, that's news to me.

As an aside -- I have noticed that my 30 kWh pack seems to cool much, much slower than the 24 kWh packs were reported to. I've seen others mention this as well. It seems as though when I QC during the day with ambient temps 80+, the pack will never cool down even if I'm driving it around. Only way to cool the pack is wait for the temps to drop at night.

Regarding the aHr -- is 80.6 after a few months on the lot really that egregious? Hx was 96.39 as well when the car was picked up. Honestly hadn't given it much thought, especially given how poor degradation others are reporting. Especially given that the aHr bounces around. Are most people getting cars off the lot with an Ahr of 82+?

arnis
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Location: Estonia, Europe

Re: 2016-2017 model year 30 kWh bar losers and capacity losses

Sun Nov 12, 2017 2:08 pm

GrowingTuna wrote:3. Battery degradation seemed to correspond to ambient temperature more than how I treated it.


Correct. Trying to peppy the battery makes almost no difference in terms of Rapid Unscheduled Degradation.
L1; L2; L3 - doesn't matter. Few hours 10 degrees hotter due to QC session - doesn't matter.

It's my understanding that the damage from high SOC comes when you are charging the battery to full or nearly so.

No. This only has a cycle degradation. This is hardly a 1-2% per year (that is what my Leaf does mostly).
Damage happen not due to charging, but due to cells being charged.
50% charged is better than 60%, is better than 70%, is better than 80%. And anything above that is already charted territory.

When you got your Leaf, BMS did not recalculate SOH, Hx values. It requires considerable discharges for BMS to notice capacity.
BMS calculates battery capacity looking at the voltage while counting how much juice has been used/added. Above 50% charge
state voltage is pretty constant. Therefore no good capacity valuation can be done.
When you got your vehicle, it was already degraded. BMS just didn't know that. Until you showed it to BMS.

If it wasn't a lease, I would return the vehicle immediately. Because it was not stored according to manufacturer's recommendations.

Though now you know what will happen with your vehicle, if you charge it to 100%. Add around 1-2% extra degradation due battery cycling to that two digit number and you get expected degradation when used and immediately charged to 100% when not.



PS: 100% on a Leaf is around 4.14V. 100% on a Tesla is 4.2V. Tesla's 100% selection defaults back to 90% after some period.
Nissan knows that their battery is s*it in heat. They don't even allow higher SOC to begin with.
We, (you guys in hot climates), can only voluntarily go lower.

Bottom line: Without fully characterizing (extensive analysis) the Leaf's cell, suggestions relating to charging are basically speculations.

BS. You don't need to have extensive analysis of banana yoghurt shelf life if you have that analysis for cherry yoghurt just to estimate
how long will it last in a fridge and how long next to keyboard and mouse :lol:
Definition of speculation is "the forming of a theory or conjecture without firm evidence." We have evidence that milk products spoil faster at room temperature compared to fridge. We have evidence that Leafy flavor spoils faster than Musky flavor.
There are joghurts that do not spoil, but our version definitely does spoil.
Suggesting keeping joghurts in the fridges is transparently sensible. Suggestion to charge to lower SOC also.
Flavor plays a role at the rate. Not on the direction of capacity slip.

What is on the other hand speculation, is that keeping Leaf's cells at 3.0V will degrade them faster, compared to, lets say 3.1V.
Short range EVs <30kWh -- Medium range: 30-60kWh -- Long range: >60kWh
Charging: Trickle <3kW -- Normal 3-22kW -- Fast 50-100kW -- Supercharging >100kW

DaveinOlyWA
Gold Member
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Leaf Number: 314199
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Re: 2016-2017 model year 30 kWh bar losers and capacity losses

Sun Nov 12, 2017 3:06 pm

GrowingTuna wrote:
And yes heat is a killer but the worst is heat, high SOC and Time. Heat you can't change but the rest you can. Don't charge up unless you can do it quickly and drive immediately. IOW; you are better off to QC in the middle of noon day Sun if you are driving right away.


Of course, but if I'm only QC to 80%, would this be such a cause for concern? It's my understanding that the damage from high SOC comes when you are charging the battery to full or nearly so. Heat compounds the damage, as well as time sitting at such a high charge. If leaving my car at 80% charge overnight is a concern, that's news to me.



Its temperature dependent. The only thing I see as certain is that the danger temperature range is not as high as we want it to be.

But the key is getting away from "As long as the SOC is XX or less, I am ok" especially temperatures are not considered.

But back to the basics. Can't change temperature and the car is there for a specific purpose. That purpose overrides everything else. Its my take that if you can get away with charging to 60% then do that especially when its hot. The "magic 80% SOC" quite simply failed us but to what degree is a mystery due to vastly different charging habits.
2011 SL; 44,598 miles. 2013 S; 44,840 miles.2016 S30 (build 10/2016)"low water marks" 26,100.2 miles.363GID Ahr 79.55Hx95.35%kwh28.1QCs227,L2's 237
My Blog; http://daveinolywa.blogspot.com" onclick="window.open(this.href);return false;

LeftieBiker
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Re: 2016-2017 model year 30 kWh bar losers and capacity losses

Sun Nov 12, 2017 7:55 pm

To put it another, simpler way: pack temperatures of 6 bars or higher are to be avoided if possible, regardless of SOC. Heat all by itself is a problem.
2013 "Brilliant Silver" SV with Premium Package and no QC, and 2009 Vectrix VX-1 with 18 Leaf cells.

The most offensive, tasteless phrase in use here is "Pulled the trigger." I no longer respond to posts that use it.

jbuntz
Posts: 69
Joined: Thu Dec 08, 2016 5:41 am
Delivery Date: 17 Dec 2016
Leaf Number: 303765
Location: New Braunfels, TX

Re: 2016-2017 model year 30 kWh bar losers and capacity losses

Sun Nov 12, 2017 8:07 pm

GrowingTuna wrote:
And yes heat is a killer but the worst is heat, high SOC and Time. Heat you can't change but the rest you can. Don't charge up unless you can do it quickly and drive immediately. IOW; you are better off to QC in the middle of noon day Sun if you are driving right away.


Of course, but if I'm only QC to 80%, would this be such a cause for concern? It's my understanding that the damage from high SOC comes when you are charging the battery to full or nearly so. Heat compounds the damage, as well as time sitting at such a high charge. If leaving my car at 80% charge overnight is a concern, that's news to me.

As an aside -- I have noticed that my 30 kWh pack seems to cool much, much slower than the 24 kWh packs were reported to. I've seen others mention this as well. It seems as though when I QC during the day with ambient temps 80+, the pack will never cool down even if I'm driving it around. Only way to cool the pack is wait for the temps to drop at night.

Regarding the aHr -- is 80.6 after a few months on the lot really that egregious? Hx was 96.39 as well when the car was picked up. Honestly hadn't given it much thought, especially given how poor degradation others are reporting. Especially given that the aHr bounces around. Are most people getting cars off the lot with an Ahr of 82+?

80Ah is pretty good compared to my 2016 that was about 72Ah at delivery.
Mfg 11/15 Del 12/16 TX 2016 SL 30kWh,
30 Apr 2017 5175 mi 324 GID Ahr 70.75 SOH 89% Hx 85.31% kWh 25.1
11 Aug 2017 11 bar 9245 mi 282 GID Ahr 61.68 SOH 77% Hx 75.83% kWh 21.9
21 Oct 2017 10 bars 12000 mi 260 GID Ahr 57.22 SOH 71% Hx 70.58% kWh 20.2

GrowingTuna
Posts: 3
Joined: Tue May 30, 2017 12:13 am
Delivery Date: 30 May 2017

Re: 2016-2017 model year 30 kWh bar losers and capacity losses

Sun Nov 12, 2017 10:04 pm

arnis wrote:
When you got your Leaf, BMS did not recalculate SOH, Hx values. It requires considerable discharges for BMS to notice capacity.
BMS calculates battery capacity looking at the voltage while counting how much juice has been used/added. Above 50% charge
state voltage is pretty constant. Therefore no good capacity valuation can be done.
When you got your vehicle, it was already degraded. BMS just didn't know that. Until you showed it to BMS.

If it wasn't a lease, I would return the vehicle immediately. Because it was not stored according to manufacturer's recommendations.


Aha -- I hadn't considered that. So it's very likely that degredation was substantially worse than the BMS was reporting. Still, this seems to be within the typical levels of capacity loss we've seen reported.

I leased the vehicle; I did my homework before getting the car and assumed degredation would be an issue. I wonder how worried Nissan is about this. Seems like this was a terrible pack to offer an 8 year warranty against degredation loss. And if the cooling issues with the 30kWh pack are (at least in part) due to the increased density as I've seen suggested quite often, it makes me wonder if this problem will be even worse in the 40 kWh pack. :shock:

lorenfb
Posts: 1389
Joined: Tue Dec 17, 2013 10:53 pm
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Leaf Number: 416635
Location: SoCal

Re: 2016-2017 model year 30 kWh bar losers and capacity losses

Mon Nov 13, 2017 12:19 am

arnis wrote:BS. You don't need to have extensive analysis of banana yoghurt shelf life if you have that analysis for cherry yoghurt just to estimate
how long will it last in a fridge and how long next to keyboard and mouse :lol:
Definition of speculation is "the forming of a theory or conjecture without firm evidence." We have evidence that milk products spoil faster at room temperature compared to fridge. We have evidence that Leafy flavor spoils faster than Musky flavor.
There are joghurts that do not spoil, but our version definitely does spoil.
Suggesting keeping joghurts in the fridges is transparently sensible. Suggestion to charge to lower SOC also.
Flavor plays a role at the rate. Not on the direction of capacity slip.


You appear to have a limited ability to structure a rational analogy. Maybe try using a coherent thinking process if it's possible,
e.g. like you may have learned in a middle school logic class.

Surely you've done a full research on the effects of charging to 100% versus a lower value as it relates to degradation for the Leaf's battery,
and have corroborative data since you're so resolute. And how about a real controlled study as for charging to 90% versus 100% over time,
and not your guessing or someone's anecdotal "experience". Again, please fully quantify the degradation delta, i.e. additional loss
in SOH per year. Additionally, please reference and fully annotate your research sources and concussions specific to the Leaf's battery
as it relates to and supports "your theories". Furthermore, data relative to the Leaf's battery versus Tesla's battery is the concern
on this forum, either in tabular or graphical form would be ideal.

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