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Re: Possible Widespread 2018 Traction Battery Quick Charge Problems

Posted: Tue Apr 03, 2018 12:02 pm
by cwleaf2
OrientExpress wrote: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.

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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.

Re: Possible Widespread 2018 Traction Battery Quick Charge Problems

Posted: Tue Apr 03, 2018 4:08 pm
by OrientExpress
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.

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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.

Re: Possible Widespread 2018 Traction Battery Quick Charge Problems

Posted: Tue Apr 03, 2018 4:30 pm
by borugee
cwleaf2 wrote: 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?

Re: Possible Widespread 2018 Traction Battery Quick Charge Problems

Posted: Tue Apr 03, 2018 5:02 pm
by LeftieBiker
OrientExpress, can you post your charge rates in KW instead of amps? That would allow instant comparisons to what other drivers are seeing.

Re: Possible Widespread 2018 Traction Battery Quick Charge Problems

Posted: Tue Apr 03, 2018 5:34 pm
by lorenfb
LeftieBiker wrote: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 ... 47#p523610

Re: Possible Widespread 2018 Traction Battery Quick Charge Problems

Posted: Tue Apr 03, 2018 5:51 pm
by SageBrush
LeftieBiker wrote: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.

Re: Possible Widespread 2018 Traction Battery Quick Charge Problems

Posted: Tue Apr 03, 2018 6:36 pm
by lorenfb
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?

Re: Possible Widespread 2018 Traction Battery Quick Charge Problems

Posted: Tue Apr 03, 2018 6:51 pm
by LTLFTcomposite
lorenfb wrote: 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?

Re: Possible Widespread 2018 Traction Battery Quick Charge Problems

Posted: Tue Apr 03, 2018 7:17 pm
by lorenfb
LTLFTcomposite wrote:
lorenfb wrote: 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.

Re: Possible Widespread 2018 Traction Battery Quick Charge Problems

Posted: Tue Apr 03, 2018 8:13 pm
by LeftieBiker
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.