2018 Leaf battery overheating

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DaveinOlyWA said:
bnewkirk said:
I just got back from a 300+ mile round trip from Centralia to Ellensburg in our 2018 SV. Much of the day the temperature was in the 90s. Did a quick charge in North Bend, but a 30 minute session only netted about 40%. Apparently the heat limited the charging. Due to traffic, we were getting pressed on time (not enough time to get another charge), so we drafted a semi into Ellensburg. Had to use AC (set at 72 with 3 fan bars) and the battery registered in the red for temp. After the car sitting in a sunny parking lot at 95 degrees for a couple hours, we went over to the QC and it took 80 minutes to bring it up from 10% to 80%, again in the red zone. This time the warning come on saying the battery is hot and we should drive conservatively. Set the cruise for 55, but as we began to go up the pass, the warning said power would be reduced and put us in 2018 turtle mode. I was in the slow lane with the semis doing 40 mph. Made it to North Bend with 20% and went to the QC and parked in the shade w/ water poured under the car for evaporation cooling. 30 minutes only netted 20%, so we went another session to get up to 60%. Then we set the cruise at 55, turned off the AC and opened the windows as we went downhill to minimize battery usage. Needless to say, it was a bit of an antsy situation. Bad traffic in Tacoma helped keep battery usage down and the turtle mode warning finally went off. South of Tacoma we drafted a semi home at 65 mph with 5% left in the battery. This was my first long trip with the car and I'm not favorably impressed. I will not take it beyond its normal charge range in hot weather again.
Thanks for the info. I will be doing trip to Yakima next week for DCFC opening there so will likely see similar temps. I am guessing you didn't have LEAF Spy? This will be first real challenge for heat issues for me. I did do Ellensburg right after their grand opening but temps only in mid 90's. Yakima is expected to be in the mid 100's so definitely a bit "warmer"

Next time you do trip, I would suggest Suncadia or something. Its a bit of a detour being 5 miles off I-90 but its a great walkabout along with a QC that does not have a timer and its generally cooler as well. Be warned, the wind there is "brisk"...
Dave: I'm looking forward to meeting you at the grand opening. For others, feel free to show up for the DCQC grand opening (free food) at Noon, Aug 2nd, 51 Firing Center Road, Yakima. From Ellensburg, drive the scenic highway 821 Yakima Canyon Rd to skip all the killer HILLS on I-82 and it drops you right at the intersection for the charging station. If you need/want a charge, plan on getting there at least an hour or two early.

bnewkirk's report is more confirmation that the 2018 Leaf without TMS is not in my future. I'm sticking with my 2011 until it's battery won't get me 10 mi RT to the grocery store. Sorry Nissan, you're not getting any more of my money until you have a TMS that keeps the battery at optimum usable temperatures and doesn't generate excessive degradation.
 
Reddy said:
DaveinOlyWA said:
bnewkirk said:
I just got back from a 300+ mile round trip from Centralia to Ellensburg in our 2018 SV. Much of the day the temperature was in the 90s. Did a quick charge in North Bend, but a 30 minute session only netted about 40%. Apparently the heat limited the charging. Due to traffic, we were getting pressed on time (not enough time to get another charge), so we drafted a semi into Ellensburg. Had to use AC (set at 72 with 3 fan bars) and the battery registered in the red for temp. After the car sitting in a sunny parking lot at 95 degrees for a couple hours, we went over to the QC and it took 80 minutes to bring it up from 10% to 80%, again in the red zone. This time the warning come on saying the battery is hot and we should drive conservatively. Set the cruise for 55, but as we began to go up the pass, the warning said power would be reduced and put us in 2018 turtle mode. I was in the slow lane with the semis doing 40 mph. Made it to North Bend with 20% and went to the QC and parked in the shade w/ water poured under the car for evaporation cooling. 30 minutes only netted 20%, so we went another session to get up to 60%. Then we set the cruise at 55, turned off the AC and opened the windows as we went downhill to minimize battery usage. Needless to say, it was a bit of an antsy situation. Bad traffic in Tacoma helped keep battery usage down and the turtle mode warning finally went off. South of Tacoma we drafted a semi home at 65 mph with 5% left in the battery. This was my first long trip with the car and I'm not favorably impressed. I will not take it beyond its normal charge range in hot weather again.
Thanks for the info. I will be doing trip to Yakima next week for DCFC opening there so will likely see similar temps. I am guessing you didn't have LEAF Spy? This will be first real challenge for heat issues for me. I did do Ellensburg right after their grand opening but temps only in mid 90's. Yakima is expected to be in the mid 100's so definitely a bit "warmer"

Next time you do trip, I would suggest Suncadia or something. Its a bit of a detour being 5 miles off I-90 but its a great walkabout along with a QC that does not have a timer and its generally cooler as well. Be warned, the wind there is "brisk"...
Dave: I'm looking forward to meeting you at the grand opening. For others, feel free to show up for the DCQC grand opening (free food) at Noon, Aug 2nd, 51 Firing Center Road, Yakima. From Ellensburg, drive the scenic highway 821 Yakima Canyon Rd to skip all the killer HILLS on I-82 and it drops you right at the intersection for the charging station. If you need/want a charge, plan on getting there at least an hour or two early.

bnewkirk's report is more confirmation that the 2018 Leaf without TMS is not in my future. I'm sticking with my 2011 until it's battery won't get me 10 mi RT to the grocery store. Sorry Nissan, you're not getting any more of my money until you have a TMS that keeps the battery at optimum usable temperatures and doesn't generate excessive degradation.

I will be there! Hopefully along with many others!
 
Yesterday, I did a longer commute on old 2014 24kWh Leaf. 250 miles, 400 km. With AC :)
Started with 100% charge at home and never recharged at destination. Vehicle was parked for hours at destination.
Took me exactly 6 DC sessions all exactly 10 minutes long. All sessions gave me ~7-7,5kWh of energy,
average charge speed was exactly 40kW (one charger was limited to 43kW, most gave me up to 49kW).
Exactly 60 minutes, therefore 40kWh. Had 3kWh to spare at arrival.
What I want to say that this is 2018 Leaf territory. Except I had to do 6x10 minute stops and 40kWh Leaf could do one
much longer break, if it did not overheat :lol:

This made me come here and mention overheating. It was 29*C in shade, 84F. With my tactics, I managed to keep battery temperature reasonable.
I started with 29,5*C and 70 minutes later it was 32*C (before first DC session). So almost no temperature increase
during 100%>>>20% discharge.
Anyway, on the way back, highest temperature was 42*C, 24*C outside.
By American standards, driving speed was not "fast enough" but it's not not like it would have been much faster with ICE.
So taking everything into account. Went 202km in 3h10min, 64km/h average trip speed. If I had taken my bimmer
and drive like I stole it, I would make that same trip 2h20min oneway. Coming back took 20 minutes more as I was discharged before departure.. So 3h30min. Would have taken 2h20min with ICE vehicle.
So I lost 50 minutes going there and 70 coming back. 2 hours. 9€ for DC sessions (plus 1€ charge taken at home).
ICE vehicle would steal 5,7 l/100km*4 * 1,4€/l=26€. So I saved 16€. Which is around 2 hours of labor (1h hour in some other countries here in EU). But I was actually resting. Soo... all in all, slightly better than a tie :)

Going back to RapidGate. Just offering cheap (actually free) advice for any engineer who F*'d up at Nissan :lol:
My proposal for Nissan (40kWh Leaf) that would be acceptable for most customers and should keep battery safe is here:
Charge limit 50kW below 35*C. Regen limit 50kW, Power limit 110kW, top speed 130km/h (even that is way too much for this vehicle* :( )
Charge rate limit 50kW at 38-40*C (less than 8TB), regen limit 30kW and power 80kW (60) , without kickdown 40kW (30), top speed 120km/h (110)
Charge rate limit 40kW at 43-45*C, reduce regen to 25kW and power limit 60kW (50), without kickdown 30kW, top speed 100km/h, display message
Charge rate limit 30kW at 48-50*C reduce regen to 15kW and power limit to 50kW (45), without kickdown 30kW (25), top speed 90km/h, display message
Charge rate limit 20kW at 50-52*C reduce regen to 10kW and power limit to 40kW (30), without kickdown 25kW, top speed 80km/h, turtle, display message.

Additional software modification for front fans: switch on if DC charging or speed below 10km/h to LOW/MID speed battery between 40-45*C, MAX speed at >48*C. These fans do have an effect, especially when DC charging and Climate Control is off and ambient considerably below battery (10-20 degrees delta). Keep fans active at LOW at AC charging if temp above 45*C.
*Additional limitation: In case of active Low Battery Warning use value in brackets "()".
In case of VLBW, engage turtle and limit power no more than 30kW, top speed ~90km/h.
They clearly made lots of mistakes (having 80kW available at 3% SOC on 24/30kWh Leaf is ridiculous, clearly idiots.


Having that much experience with LeafSpy monitoring and changing behaviour I'm convinced: DC charging heat generation is half of the problem. The other half happens on the move. And latter one can be changed to reduce charging speed problem without really reducing average trip speed.

*has been confirmed by many, for example (4:19 in the video clearly states what happens if driven at current top speed):
https://www.youtube.com/watch?v=MpUyspG2Mio&t=720s
 
Arnis, I would gladly "race" you although it wouldn't be much of a race since I would be halfway home by the time you crossed the finish line
 
For anyone interested in the DCFC buildup in Central WA

http://daveinolywa.blogspot.com/2018/08/west-coast-electric-highway-goes-inland.html
 
I-80 through Nebraska is getting 3 stations spaced about 120 miles apart through Electrify America. Not so big of deal for Leaf's due to overheating, but a huge deal for the Bolt's that paid for CCS.
 
hyperionmark said:
I-80 through Nebraska is getting 3 stations spaced about 120 miles apart through Electrify America. Not so big of deal for Leaf's due to overheating, but a huge deal for the Bolt's that paid for CCS.

Phase one electrifies main highway corridors and will be minimal in most areas and based on EV density. In WA, they are like 50 miles apart but there is also several other options.

Keep in mind; there are 5 phases so VW is no where near done with Nebraska.
 
DaveinOlyWA said:
hyperionmark said:
I-80 through Nebraska is getting 3 stations spaced about 120 miles apart through Electrify America. Not so big of deal for Leaf's due to overheating, but a huge deal for the Bolt's that paid for CCS.

Phase one electrifies main highway corridors and will be minimal in most areas and based on EV density. In WA, they are like 50 miles apart but there is also several other options.

Keep in mind; there are 5 phases so VW is no where near done with Nebraska.
If they are basing it on EV density I'm surprised they put any in Nebraska at all. Our local utility in Omaha is doing a $4,000 cash rebate once you register a new EV and $3,000 immediately off a new Leaf. They have had 10 people so far use it in the first 2 months, haha. It only gets worse as you head out into rural Nebraska.
 
hyperionmark said:
DaveinOlyWA said:
hyperionmark said:
I-80 through Nebraska is getting 3 stations spaced about 120 miles apart through Electrify America. Not so big of deal for Leaf's due to overheating, but a huge deal for the Bolt's that paid for CCS.

Phase one electrifies main highway corridors and will be minimal in most areas and based on EV density. In WA, they are like 50 miles apart but there is also several other options.

Keep in mind; there are 5 phases so VW is no where near done with Nebraska.
If they are basing it on EV density I'm surprised they put any in Nebraska at all. Our local utility in Omaha is doing a $4,000 cash rebate once you register a new EV and $3,000 immediately off a new Leaf. They have had 10 people so far use it in the first 2 months, haha. It only gets worse as you head out into rural Nebraska.

Well, it is based on EV density and it sounds like Nebraska is simply more "in the way" or a politically correct "on the way" to EVland
 
What actual temp (F) is considered high and "detrimental" for the life of the 40 kWh battery. Greater than 90? Greater than 120? Assuming a 12 hr period here as it appears the battery doesn't drastically dissipate the heat once it is gained.
 
jdcbomb said:
What actual temp (F) is considered high and "detrimental" for the life of the 40 kWh battery. Greater than 90? Greater than 120? Assuming a 12 hr period here as it appears the battery doesn't drastically dissipate the heat once it is gained.

When the battery temp gauge gets into the red part, the LEAF will throttle back the amount of charging and power available.

battery-temp.png
 
Thanks..aware of this. Just curious to understand what is a "bad" temperature (in F, not by vague bars) for the 18 MY?

And wondering if 95 F is actually within normal operating limits and won't cause significantly faster degradation than say a "comfortable" 78 F temp.
 
jdcbomb said:
What actual temp (F) is considered high and "detrimental" for the life of the 40 kWh battery. Greater than 90? Greater than 120? Assuming a 12 hr period here as it appears the battery doesn't drastically dissipate the heat once it is gained.

Its a sliding scale that considers SOC, time and temperature so your question is all but unanswerable. Some tidbits to consider;

The most efficient charge (that gets the most range per unit of time) is when starting charge with pack temperature in the mid to low 80's ºF.

**80% SOC is good but 70% SOC is better; recommendation is ALWAYS charge to cover your needs. ef everything else. **

Heat or heavy QC is not your main worry. Its "time" at high SOC.

Heat dissipation is almost completely dependent on the delta between the pack and the ambient. So if you live in a 24/7 hot area, I would not charge to full EVER. (see "**" above)
 
jdcbomb said:
What actual temp (F) is considered high and "detrimental" for the life of the 40 kWh battery. Greater than 90? Greater than 120? Assuming a 12 hr period here as it appears the battery doesn't drastically dissipate the heat once it is gained.

"Detrimental" isn't really how it works.

Li ion batteries have side reactions that remove active Lithium and otherwise degrade the anodes and cathodes.

These reactions happen in any Li ion battery at any operational temperature. Like most chemical reactions, these reactions seem to follow an Arrhenius relationship, going faster at higher temperatures. A temperature higher by 10C or a bit less would double the rate of capacity loss.

So if your "normal" battery temperature is 25C, a day trip that raises that to 35C will roughly remove an extra day of battery life. A day trip that raises battery temperature to 45 C would remove roughly three extra days of battery life.

This is a crude back of envelope type calculation. A better calculation could be done by considering the warmup time and the cooling time, and using the roughly 8C best fit for the Arrhenius relationship. The results wouldn't be much different.

If you do a trip that adds 10C once a year, I doubt if you can observe the faster rate of capacity decline, even with multiple cars driven exactly the same. If you do a trip that adds 30C three times a week, different story.
 
jdcbomb said:
Thanks..aware of this. Just curious to understand what is a "bad" temperature (in F, not by vague bars) for the 18 MY?

And wondering if 95 F is actually within normal operating limits and won't cause significantly faster degradation than say a "comfortable" 78 F temp.

That's about 10C warmer, so yes, the battery would degrade faster. At a "comfortable" 25 C (78 F) and often less, the battery would last more than three times the warranty.

http://www.nec.com/en/global/techrep/journal/g12/n01/pdf/120112.pdf
 
"Detrimental" isn't really how it works.

It's close enough. Assuming that 3% degradation per year is "normal" (we wish!) then anything that raises the rate substantially above that could be considered "detrimental." In the case of the 40kwh pack (which I am probably going to name something less than flattering) time seems to once again be a major factor, as it was with the original "Canary" pack, so heat once again has some real competition. I haven't done a LeafSpy reading since December; once it warms up I'll start doing it monthly again, and will have an annual figure for my car, for the first year, this month.
 
jdcbomb said:
What actual temp (F) is considered high and "detrimental" for the life of the 40 kWh battery.
Detrimental to whom ? Nissan chooses according the warranty. If you want your battery to do better than have ~ 65% of new capacity by year 8 or so, do not follow Nissan's advice.
 
Thanks for all the replies. I know the question and even the word "detrimental" is vague and subjective, but I believe my point was to see at what temperature do we believe (not Nissan necessarily) would cause the most degradation. Indeed this also requires a time frame, of which I think 12 to 24 hr minimum period would be sufficient to observe an effect versus over several days (or maybe not?).
 
SageBrush said:
jdcbomb said:
What actual temp (F) is considered high and "detrimental" for the life of the 40 kWh battery.
Detrimental to whom ? Nissan chooses according the warranty. If you want your battery to do better than have ~ 65% of new capacity by year 8 or so, do not follow Nissan's advice.

And don't live in Phoenix.
 
jdcbomb said:
Thanks for all the replies. I know the question and even the word "detrimental" is vague and subjective, but I believe my point was to see at what temperature do we believe (not Nissan necessarily) would cause the most degradation. Indeed this also requires a time frame, of which I think 12 to 24 hr minimum period would be sufficient to observe an effect versus over several days (or maybe not?).
A binary answer or threshold does not exist. The very approximate answer is that battery will age twice as fast for every 7 - 10C increase in temperature. This is based on Arrhenius.

Is it clear how this works then ?
As one example, 4 hours at 20C has about the same aging as one hour at 35 -40 C

A LEAF that is rapid-gating has a battery temperature of ~ 50 C. Compared to the 20 C or so that Nissan uses for its warranty based engineering designs, the battery will age 8x - 16x as fast during the affected time at 50C. To go back to your implied question in terms of a battery heating up to rapid-gate temperature, the cooling down period ~ follows Newton's law of cooling. Integrate that function and apply the temperature average to Arrhenius' law.

I apologize if this is greek to you.
 
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