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Re: Possible Widespread 2018 Traction Battery Quick Charge Problems

Posted: Fri Apr 06, 2018 1:59 am
by kennethbokor
hill wrote:
kennethbokor wrote:......snip...... I agree with this OP, I don't think we need more pages of data on why this happens and accept that fact that it does and its part of the design/build of the new Leaf.
That's very magnanimous, to simply accept the fact that Corporate Nissan continually churns out traction packs with the resiliency of a POS. Thats great if owners really don't mind an ever larger pack that's ever more prone to loose capacity as fast, or even faster than the 30's - or our original (vin 000659) 21kWh usable original POS.
(Not IF, but) When these larger Nissan packs quickly degrade & end up with a paltry cold weather range of under 50 miles - because Nissan was too cheap or profit hungry or too lazy to manufacture an authentic thermal management system - but instead, chose to continue to pack even more modules close together, where even MORE trapped heat will result in packs faster degradation - especially in all the hot areas of the country ....
all of us poor slobs will welcome all the newcommers - recently suckered into this poorly designed - virtually absent thermal management system.
Yes - THAT'S why your QC Speeds throttle so quick ... it's in hope the packs can make it to the end of warranty before they literally cook their self down to the paltry range of all of us remaining old timers.
"Possible Quick Charge Problems"?
It's not a possibility, & it's not a problem .... it's Nissan's carefully crafted attempt to cover up their thermal management huge fail.
How's THAT for a 'fact' for owners to simply 'accept' .
.

Hi Hill, good points of course you make but really don't see what can be done at this point other than understanding. Nissan is not going to change the 40kWh Leaf so as I said before for most use cases I don't see a high degree of problems. The vast majority will drive daily and plug in at home overnight to rinse and repeat. They won't buy leaf spy or watch temps, etc. They will just get used to the features/controls and get in and drive as per normal, since they are well within battery range for daily uses. They will rely on Nissan's Battery Warranty for some level of comfort or they will lease for shorter term and not care.

Re: Possible Widespread 2018 Traction Battery Quick Charge Problems

Posted: Fri Apr 06, 2018 2:25 am
by LeftieBiker
They will just get used to the features/controls and get in and drive as per normal, since they are well within battery range for daily uses.
Except that we don't know that Summer driving in hot weather will be "well within battery range for daily uses." On what are you basing this notion? The 30kwh Leaf, which is the closest relative we have to the 40kwh Leaf?

Re: Possible Widespread 2018 Traction Battery Quick Charge Problems

Posted: Fri Apr 06, 2018 4:13 am
by kennethbokor
LeftieBiker wrote:
They will just get used to the features/controls and get in and drive as per normal, since they are well within battery range for daily uses.
Except that we don't know that Summer driving in hot weather will be "well within battery range for daily uses." On what are you basing this notion? The 30kwh Leaf, which is the closest relative we have to the 40kwh Leaf?

Well I'm guessing that if someone is driving 50-75 miles a day, that battery range will be plenty enough to support that. Even here in Canada with -25C, early 2018 Leaf owners were reporting 30-45% drop in range, so normal range is 240KM, so even 120-140KM per day is more than enough for most daily drives. My normal daily use is about 50-70kms.

I don't think even with outside air temps of 30C or more that you will loose 50% range in the new leaf, with no DCFC-ing? Just on one charge from having it plugged in at home overnight?

Re: Possible Widespread 2018 Traction Battery Quick Charge Problems

Posted: Fri Apr 06, 2018 6:05 am
by LeftieBiker
I don't see why you are assuming that people typically drive no more than 50-75 miles a day. For commuting that's likely right, but what about trips not related to commuting?

Re: Possible Widespread 2018 Traction Battery Quick Charge Problems

Posted: Fri Apr 06, 2018 6:43 am
by Evoforce
LeftieBiker wrote:I don't see why you are assuming that people typically drive no more than 50-75 miles a day. For commuting that's likely right, but what about trips not related to commuting?
In addition to people buying the car with longer range who have longer miles of commuting. You also rightly pointed out those who expect to use it on trips. People want to no longer need or rely on an ICE.

Re: Possible Widespread 2018 Traction Battery Quick Charge Problems

Posted: Fri Apr 06, 2018 7:06 am
by SageBrush
The 2018 LEAF DCFC should come with a big footnote that reads "up to 45 kW, as battery temperature and other variables allows."

Or just give up on the DCFC sham altogether and advertise DC L2+ speeds

Perhaps we need a new acronym: DCSC "DC slow charging."

Re: Possible Widespread 2018 Traction Battery Quick Charge Problems

Posted: Sat Apr 07, 2018 7:20 am
by RegGuheert
Nissan: "It's not a bug, it's a feature!":


Re: Possible Widespread 2018 Traction Battery Quick Charge Problems

Posted: Sat Apr 07, 2018 10:28 am
by lorenfb
lorenfb wrote:For those that have access to a 2018 Leaf, do QC charging, and use LeafSpy, your help obtaining battery data on that vehicle
would be very useful in determining what battery parameter could be contributing to having the charging time progressively
lengthened during a long distance trip. It appears that the 2018 Leaf’s BMS controller is reducing the charging current as the
battery gets progressively warmer during a lengthy trip. This has not been the case for earlier Leafs even though the BMS does
reduce the charging current over time for the earlier Leafs, but it appears not based on temperature nor based on the number
of previous QCs during a trip.

The process should only take a couple of minutes during the starting phase of the QC to obtain the data:

1. Once the vehicle is parked adjacent to the QC with the Leaf’s power still on with no accessories turned-on, e.g. the fan/AC,
measure the battery voltage (V1). It should be greater than 325 volts. Then measure the battery temperature (T - degrees C).
Write these values down.
2. Next the charging voltage (V2) and charging current (I) need to be written down immediately once the QC device begins
the charging process
using LeafSpy. If the QC device provides these values, just use those values displayed on the QC
device like in this post; http://mynissanleaf.com/viewtopic.php?f ... 70#p523610
3. Once all the data are taken and time permits, please post them in this thread using the following form;
V1 - XXX, V2 - XXX, T - XX, I - XX
4. The data will then determine the battery resistance by this calculation; battery resistance = (V2 - V1) / I
As an example, V1 = 355 volts, V2 = 365 volts, I = 80 amps, then battery resistance = .125 ohms or 125 mohms.
Battery resistance varies with temperature, so it's critical to determine the temperature at the being of the charging process.

Based on your values and other’s values, a comparative analysis between the early Leafs and the 2108 Leaf should provide
insight into how the chemistry might be different and what one might expect about long term battery degradation the result
of lengthy and multiple QCs combined with high speed driving during a long trip.

Thanks for your help.
Doing multiple QCs yesterday using both ChargePoint & EVgo QCs, it took about 10-15 seconds to perform the above test.
The calculations from the data correlated with battery resistance data doing the LeafDD battery load test versus the above,
i.e. determining battery resistance during a QC mode.

Re: Possible Widespread 2018 Traction Battery Quick Charge Problems

Posted: Sat Apr 07, 2018 1:34 pm
by DaveinOlyWA
Pack Volts Pack Amps Pack T1 F Pack T2 F Pack T4 F
344.5 0 83.1 80.1 75
344.83 0 83.1 80.1 75
344.83 0.061 82.9 80.1 75
349.25 -85.082 82.9 79.9 75
351.36 -119.445 82.9 79.9 74.8



338.11 0 104 100 91.2
338 0 104 100 91.2
338.4 -0.03 104 100 91.2
338.3 0.061 104 100 91.2
338.4 0.122 104 100 91.2
341.57 -74.065 104 100 91.2
342.34 -77.453 104 100 91




348.48 0 111.2 106.7 97
348 0 111.2 106.7 97
348.67 0.061 110.7 106.2 96.4
349.73 -16.509 110.7 106.2 96.4
351.36 -68.023 110.7 106.2 96.4
351.84 -68.542 110.7 106.2 96.4

Re: Possible Widespread 2018 Traction Battery Quick Charge Problems

Posted: Sat Apr 07, 2018 4:25 pm
by lorenfb
DaveinOlyWA wrote:Pack Volts Pack Amps Pack T1 F Pack T2 F Pack T4 F
344.5 0 83.1 80.1 75
344.83 0 83.1 80.1 75
344.83 0.061 82.9 80.1 75
349.25 -85.082 82.9 79.9 75
351.36 -119.445 82.9 79.9 74.8
(351 - 344) / 119 = 59 mohms


DaveinOlyWA wrote:338.11 0 104 100 91.2
338 0 104 100 91.2
338.4 -0.03 104 100 91.2
338.3 0.061 104 100 91.2
338.4 0.122 104 100 91.2
341.57 -74.065 104 100 91.2
342.34 -77.453 104 100 91
(342 - 338) / 77 = 52 mohms



DaveinOlyWA wrote:348.48 0 111.2 106.7 97
348 0 111.2 106.7 97
348.67 0.061 110.7 106.2 96.4
349.73 -16.509 110.7 106.2 96.4
351.36 -68.023 110.7 106.2 96.4
351.84 -68.542 110.7 106.2 96.4
(351 - 348) / 69 = 43 mohms

Using your charging data (I assume), the 2018 40 kWh Leaf battery has about the same battery resistance (55 mohms) as the 24 kWh battery.
Given that adding more cells in parallel (effectively) for more energy when using the same chemistry should have resulted in about .60 (24/40)
the battery resistance (on average) of the 24 kWh battery resistance, so one can possibly conclude a change in battery chemistry (worse).
Additionally, since the 2018 battery is running hotter with the approximate same battery resistance, i.e. same internal heat generation,
one would assume that its thermal resistance to ambient has increased. Reg/LeftieBiker have noted/implied this up-thread.

A thanks to Dave. At least further insight now exists about the 40 kWh battery and that more data will be obtained over time.
This obviously is not to be considered a rigorous analysis, but just a simple approximation test. Hopefully I didn't misinterpret what he did.