Possible Widespread 2018-19 Traction Battery Quick Charge Problems
- Thread starter Evoforce
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Mid-center on the jauge seems to be around 30ºC (86º F). at that temperature you are supposed to get 39 kW charge so with your 35-36 kW you are even lower than average. But it gets interesting if you're doing a second and third QC with higher temps on the jauge.OrientExpress said:
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.
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.
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=27&t=25519&start=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.
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=27&t=25519&start=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.
kennethbokor
Well-known member
lorenfb said:
Well, I think we all know that Nissan is purposely throttling DCFC inputs based on battery temps to keep temps in check and prolong battery life. So I don't think we need more info on this subject stating that fact. I posted a response in this thread from Nissan Corporate that basically said this slowdown is meant to do what it does.
So with regards to why temps are a potential concern?
Here is some info on the new Leaf's Pack:
- 40kWh improved battery pack (33% more density and energy), yet in same packaging/space as previous pack, still retains passive air cooling, 192 prismatic form factor lithium cells, improved chemistry (nickel-manganese-cobalt with graphite anode), .9mm thicker and use a thinner separator to reduce internal resistance, bundled 8 cells per module, 24 modules total. Can retain 90% of its capacity after 500 charge/discharge cycles or over 100,000 kMs/60,000 miles
This info is all from Nissan.
From what I've seen and read, Nissan has confidence in this "improved chemistry" for this pack. However, they know that passive air cooling combined with more dense pack will drive up temps, even with this new chemistry.
So, there is nothing that Nissan is going to do to the BMS (tweak it) or anything else for the 40kWh Leaf. What I've been telling interested folks is that if you can live with the range it gives you and the ability to multi-fast charge successively with a throttle-down after DCFC #1 or #2 (depending on outside weather/temps as in summer the throttling will probably happen after DCFC #1), then buy the Leaf. It's a great car and for a vast majority of users, will do the job. I think Byorn did a great job with his recent testing and summarizing that for DCFC-ing, keep the GOM no lower than 20% before charging and stop at 80% - if you do alot of longer trips. This seems to be the best "formula" for keeping the battery temps in check.
So 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.
Nissan screwed the pooch on QCFC, although it remains to be seen (or figured out) whether even one charging session at 45 kW will be available in warm/hot weather.
The no less important question is how hot the battery gets throughout the summer. I asked Joe "the mechanical engineer" in another thread how much heat dissipation drops on a 95F day compared to 35F based on a simple model of conduction but no answer was forthcoming so I'll provide it here: 75%
Ignoring just for a moment other variables in play like specific heat, better ventilation during driving and time, we are starting the game from the sqrt(0.25) = 50%, or about 11 kW based on the reports of 22 kW throttling when the battery reaches 115F. I am not saying that the LEAF will be throttled to 11 kW in the summer or that the battery will live at 115F for months on end. I am saying that the LEAF battery in the 40 kWh model appears to be even more vulnerable in warm climates than prior models and more information is absolutely required to be an informed buyer.
Caveat Emptor. Or just plop down $30k based on "confidence" from Nissan Corporate and a battery warranty that will keep the car running at something over 60% of new range for 8 yrs/ 100k miles.
The no less important question is how hot the battery gets throughout the summer. I asked Joe "the mechanical engineer" in another thread how much heat dissipation drops on a 95F day compared to 35F based on a simple model of conduction but no answer was forthcoming so I'll provide it here: 75%
Ignoring just for a moment other variables in play like specific heat, better ventilation during driving and time, we are starting the game from the sqrt(0.25) = 50%, or about 11 kW based on the reports of 22 kW throttling when the battery reaches 115F. I am not saying that the LEAF will be throttled to 11 kW in the summer or that the battery will live at 115F for months on end. I am saying that the LEAF battery in the 40 kWh model appears to be even more vulnerable in warm climates than prior models and more information is absolutely required to be an informed buyer.
Caveat Emptor. Or just plop down $30k based on "confidence" from Nissan Corporate and a battery warranty that will keep the car running at something over 60% of new range for 8 yrs/ 100k miles.
The quick jump in temperature while quick charging sure seems to imply a higher resistance, but impaired heat dissipation in the summer is the more important question overall since it is the proximate cause of degradation. Unluckily for LEAF owners, these two effects work in concert.lorenfb said:
hill
Well-known member
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.kennethbokor said:
(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' .
.
It’s interesting to hear the head-in-the-sand approach some are advocating when it comes to obtaining a little quantitative
data to better understand the 2018 40kWh Leaf battery QC issues exposed in this thread. Without a simple data gathering
and analysis, would one expect the 2018 40 kWh Leaf battery degradation to follow the same 30 kWh battery degradation,
or worse, that many 30 kWh Leafs have exemplified? Having a quantitative parameter, e.g. battery resistance, as a differentiator
between the 24/30/40 Leaf batteries would provide a valuable insight into the batteries’ chemistries and heat related degradations.
Remember, internal battery heat generation, i.e. charging and driving, just compounds that which develops from ambient.
data to better understand the 2018 40kWh Leaf battery QC issues exposed in this thread. Without a simple data gathering
and analysis, would one expect the 2018 40 kWh Leaf battery degradation to follow the same 30 kWh battery degradation,
or worse, that many 30 kWh Leafs have exemplified? Having a quantitative parameter, e.g. battery resistance, as a differentiator
between the 24/30/40 Leaf batteries would provide a valuable insight into the batteries’ chemistries and heat related degradations.
Remember, internal battery heat generation, i.e. charging and driving, just compounds that which develops from ambient.
tattoogunman
Well-known member
hill said:
Nissan has said as much - someone I follow on YouTube (Nikki of Transport Evolved) got an official response from Nissan saying the car is designed to throttle back the charging on purpose to prolong battery life. I agree and I really do not understand why Nissan didn't go active thermal management, especially since the 60kWh version is supposed to have it.
kennethbokor
Well-known member
hill said:
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.
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?
kennethbokor
Well-known member
LeftieBiker said:
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?
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?
Evoforce
Well-known member
LeftieBiker said:
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.
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."
Or just give up on the DCFC sham altogether and advertise DC L2+ speeds
Perhaps we need a new acronym: DCSC "DC slow charging."
RegGuheert
Well-known member
Nissan: "It's not a bug, it's a feature!":
[youtube]http://www.youtube.com/watch?v=660EV142-Io[/youtube]
[youtube]http://www.youtube.com/watch?v=660EV142-Io[/youtube]
lorenfb said:
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.
DaveinOlyWA
Well-known member
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
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
DaveinOlyWA said:
(351 - 344) / 119 = 59 mohms
DaveinOlyWA said:
(342 - 338) / 77 = 52 mohms
DaveinOlyWA said:
(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.
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