Possible Widespread 2018-19 Traction Battery Quick Charge Problems

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Weasel wording aside, the verbiage that the throttling only kicks in with repeat QC stops is I suspect going to turn out to not be true on hot summer days (> 90F)
 
If Hx is the average value of the battery resistance (mohms) over time and NOT the present value for the battery resistance,
(battery resistance changes with temp and over time), then Hx could possibly represent the average battery resistance
over time.

It's always been my guess that Hx represents the resistance (inverse resistance, more accurately) at the moment the reading is taken, while SOH is an average of Hx over time. If you take "H" to mean "Health" then this makes sense.
 
SageBrush said:
Weasel wording aside, the verbiage that the throttling only kicks in with repeat QC stops is I suspect going to turn out to not be true on hot summer days (> 90F)

A LEAFer in AZ ha throttling issues on first QC but her situation is uniq... ah, hopeless.

She lives in apt, has charging in uncovered parking lot. Charge finishes in afternoon and she leaves early evening. Dk if this her normal daily routine but she was getting 22 kw on first QC of the day. Its only March... or April if you will. She has no chance of being happy...
 
LeftieBiker said:
If Hx is the average value of the battery resistance (mohms) over time and NOT the present value for the battery resistance,
(battery resistance changes with temp and over time), then Hx could possibly represent the average battery resistance
over time.

It's always been my guess that Hx represents the resistance (inverse resistance, more accurately) at the moment the reading is taken, while SOH is an average of Hx over time. If you take "H" to mean "Health" then this makes sense.

As I understand you, you're saying Hx is the present state of health of the battery versus SOH which is its average over time, right?
If so, it's not resistance nor its inverse (conductance), right? I think Gary (Gid) assigned the names and meanings when the Leaf BMS
was analyzed. If we agree, let's move on.
 
I think that whatever Hx is, it's a momentary reading, while SOH is a longer term average. It appears that, barring a BMS reset, these two LeafSpy readings may allow a valid comparison of degradation between the 24, 30 and 40kwh packs.
 
LeftieBiker said:
I think that whatever Hx is, it's a momentary reading, while SOH is a longer term average. It appears that, barring a BMS reset, these two LeafSpy readings may allow a valid comparison of degradation between the 24, 30 and 40kwh packs.

This is plausible. Hx changes frequently thru out the day. SOH? Not so much.
 
I've got an '18 LEAF SL this week, and tried some quick charges with it yesterday, here is the second QC I did which ran for 35 minutes. It did not seem any different from how my 2014 charges at this QC.

leaf2QC-1.jpg


leaf2QC-2.jpg


leaf2QC-3.jpg


leaf2QC-4.jpg


leaf2QC-5.jpg


leaf2QC-6.jpg


leaf2test.jpg


On Thursday we will be driving it from Monterey to South Lake Tahoe and back. That will be the real test I think.
 
DaveinOlyWA said:
LeftieBiker said:
I think that whatever Hx is, it's a momentary reading, while SOH is a longer term average. It appears that, barring a BMS reset, these two LeafSpy readings may allow a valid comparison of degradation between the 24, 30 and 40kwh packs.

This is plausible. Hx changes frequently thru out the day. SOH? Not so much.

This graphic in the TM-Spy would be helpful in the LeafSpy for a comparative analysis of the 24/30/40 kWh batteries.

http://mynissanleaf.com/viewtopic.php?f=44&t=14285&p=523547#p523547
 
OrientExpress said:
I've got an '18 LEAF SL this week, and tried some quick charges with it yesterday, here is the second QC I did which ran for 35 minutes. It did not seem any different from how my 2014 charges at this QC.

leaf2QC-1.jpg


leaf2QC-2.jpg


leaf2QC-3.jpg


leaf2QC-4.jpg


leaf2QC-5.jpg


leaf2QC-6.jpg


leaf2test.jpg


On Thursday we will be driving it from Monterey to South Lake Tahoe and back. That will be the real test I think.
Hello, did you check your battery temperature when starting the quick charges?

P.S.: Nice color! Nissan doesn't offer this colour here in Europe.
 
Hello, did you check your battery temperature when starting the quick charges?

Yeah for that one it was left of center.

Today I did the first of my 18 LEAF tests with a RT from south San Jose to Monterey and back. It was a total of 128 miles RT and I had 17% stated reserve or 31 Miles left at the end. I L2 charged last night for about 4 hours to get to 100%. Temp was left of midrange when I started. The road course was highway @65, Canyon and hilly twisties, @45, Highway 1 @ 55, and city driving @35. When I finished the Battery Temp was mid range.

I did do one thing different than I normally do when I drive this road, I kept to the posed speed limits, much to the chagrin of my fellow drivers! I did find that I could outdrive them on the twisties using e-Pedal to modulate speed and the Vehicle Dynamic Control for the turns. The only other car I had driven with VDC was a 911, and it really helps carving into the curves.

Observations of the 18 LEAF in general:
This was my first time spending extended time with the car since the Las Vegas product reveal, and my overall impressions were good. ProPilot is great, much better than the competing systems from Toyota, VW, and GM. Better logic for seeing and reacting to things ahead. Ride is smooth and firm, seats are comfortable, cabin climate and the Apple play are good. Only thing I noticed is the cabin picks up a lot of tire and some wind noise. No rattles so far.

I QC'd at the Drive the Arc L3 by my house, and ran it for 45 minutes. It started out at 100A (35.5kW), at 30 minutes I was at 98A (34.79 kW), and when I finished at 45 minutes I was down to 62A (22.01kW).

Battery Temp when I finished was right of center mid-way. Went from 17% to 86%. I'll L2 it up to 100% tonight.

leaf2QC-2-1.jpg


leaf2QC-2-2.jpg


leaf2QC-2-3.jpg


So far nothing observed out of the unusual compared to every other LEAF I've QC'd (and I have done every model year since 2011)

Wednesday will be the important test, when I continue the trip from San Jose to South Lake Tahoe. This will have more interstate, and of course big elevation gains on Highway 50. Nice thing about 50 is that it is mostly 2 lane, and drivers aren't in a hurry. We expect that trip including Charge stops should be about 7 hours vs 5.5~6 hours if we drive and stop for lunch.
 
cwleaf2 said:
Thanks for your rapid charging graph! This is exactly the same problem as we saw on your LEAF 2.0 in Europe.

Here are the numbers from Bjørn's 600 mile yesterday in Norway:

Second charge:
T1: 32,0º T2: 29,7º T3: 22,5º SOC: 16,1% Charge: 42.6 kW
T1: 40,4º T2: 38,9º T3: 30,6º SOC: 42,4% Charge: 44.4 kW
T1: 44,0º T2: 42,6º T3: 34,1º SOC: 54,3% Charge: 45.0 kW
T1: 47,9º T2: 46,6º T3: 37,9º SOC: 68,5% Charge: 36.2 kW
T1: 48,3º T2: 47,0º T3: 38,4º SOC: 70,8% Charge: 34.3 kW

Third charge:
T1: 45,4º T2: 41,8º T3: 32,6º SOC: 48,7% Charge: 22.1 kW
T1: 46,6º T2: 42,7º T3: 33,3º SOC: 56,1% Charge: 21.1 kW

Later charge:
T1: 41,0º T2: 34,4º T3: 23,5º SOC: 34,9% Charge: 25.9 kW
T1: 44,4º T2: 37,7º T3: 26,6º SOC: 54,7% Charge: 26.1 kW
T1: 46,0º T2: 39,2º T3: 28,5º SOC: 64,4% Charge: 26.0 kW

Latest charge:
T1: 37,1º T2: 29,6º T3: 18,4º SOC: 15,1% Charge: 30.9 kW
T1: 42,9º T2: 36,2º T3: 25,7º SOC: 52,2% Charge: 29.7 kW
T1: 44,4º T2: 37,8º T3: 27,6º SOC: 60,9% Charge: 29.2 kW

Last charge:
T1: 39,6º T2: 32,7º T3: 22,2º SOC: 21,8% Charge: 26.1 kW
T1: 42,3º T2: 35,3º T3: 24,8º SOC: 48,0% Charge: 26.4 kW
T1: 44,3º T2: 37,3º T3: 26,7º SOC: 59,2% Charge: 27.0 kW

This also show that T1 / T2 / T3 battery banks cooling is not similar. They are vastly different. T1 bank Do not seem to cool down, while T3 - Seems to cool down quickly. May be the location of the battery. Is T3-battery bank better ventilated?
 
LeftieBiker said:
OrientExpress, can you post your charge rates in KW instead of amps? That would allow instant comparisons to what other drivers are seeing.

Just multiply Volts X Amps shown on the charger screen to get kW, i.e. (38, 34, 25, 23, 12, 8 kW). The voltage in all cases is essentially
constant
at about 390 volts, except when the QC is delivering 100 amps and the output voltage drops a little. Data used from here;

http://mynissanleaf.com/viewtopic.php?f=27&t=25519&p=523647#p523610
 
LeftieBiker said:
OrientExpress, can you post your charge rates in KW instead of amps? That would allow instant comparisons to what other drivers are seeing.
If you cannot multiply by 0.4 you have bigger problems than being lazy.
 
There's been essentially no discussion or focus of what's causing the Leaf2 battery to increase in temp more rapidly than early batteries.
Yes, most obviously it's the chemistry and potentially the battery's thermal resistance to ambient. But specifically what measurable
battery parameter has a changed, causing the higher rate of change of battery temperature. The most obvious and easiest to
determine is the battery's internal resistance, where battery power consumption and heating is I^2 (charging current squared)
times the battery's internal resistance. This can be determined easily, as has been expressed numerous times on the forum.
So if it turns out that this Leaf2 battery has a higher internal resistance, e.g. from chemistry change, that would help example the greater
rate of change of Leaf2's temperature while charging. Additional tests could easily be developed to the determine if the thermal
resistance of the Leaf2 battery may have changed too, further contributing to the battery's higher remaining temp after multiple QCs.

After about eight pages of posts about the reduction of charging current during multiple successive charging sessions and the correlation
with the battery temperature with the Leaf2 battery, isn't time to now to try and understand what the cause/causes might be?
 
lorenfb said:
After about eight pages of posts about the reduction of charging current during multiple successive charging sessions and the correlation with the battery temperature with the Leaf2 battery, isn't time to now to try and understand what the cause/causes might be?
Isn't that Nissan's job?
 
LTLFTcomposite said:
lorenfb said:
After about eight pages of posts about the reduction of charging current during multiple successive charging sessions and the correlation with the battery temperature with the Leaf2 battery, isn't time to now to try and understand what the cause/causes might be?
Isn't that Nissan's job?

Yes it is, but it may help to further understand the evolution of the Leaf batteries from a more technical aspect. Besides, if the battery
resistance is causing heat problems while charging, additional heat from driving will also be problematic.
 
Just multiply Volts X Amps shown on the charger screen to get kW, i.e. (38, 34, 25, 23, 12, 8 kW). The voltage in all cases is essentially
constant at about 390 volts, except when the QC is delivering 100 amps and the output voltage drops a little.

Yes, and I know. I don't want to do that for every charging screen I see.

What is different about the 40kwh Leaf? Higher energy density, apparently from larger cells squashed into a space that used to have a little airflow inside to aid the modest convection cooling. As other car companies ensure that their packs are actively cooled, Nissan is going in the exact opposite direct - making sure that their packs get cooled as little as possible. The only reason I'm likely to lease a 2018 Leaf, aside from the lack of direct competition, is that I believe I can fit it in my garage, and then cool the garage during heat waves. But that doesn't mean I'm not pissed off about it, or that I'm sure I'm not making a big mistake.
 
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