Evoforce
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Location: Fountain Hills Arizona

Re: Why the LEAF Gen 2 and not the 220 miles Tesla Model 3?

Tue Sep 12, 2017 5:37 am

Nope, the Leaf gen 1.5 is not the smart choice. Better looks than gen 1 and more battery but it doesn't go far enough with a few things.

Probably only 110ish freeway miles at 65 mph at normal ambient temperatures but still NO thermal cooling for hot temps and charging. Is it better than the three Leafs currently in our family? Yes, on range but not up to speed to compete with Bolt and Tesla.

Nissan is still suspect when it comes to battery degradation and rated distance. Other than that, it is a well made car and we love our cars. We are disappointed that Nissan has not stepped up to the plate to have equaled the range of the Bolt or Model 3. It is also equally a let down that they have not truly addressed their battery degradation problems.

I believe they got caught flat footed...
*2011 Leaf 1 bought 2/28/15 @ 28,000ish mi 10 bar (8 bars @ 11/25/15 @ 37,453 ) (New lizard @ 39,275 mi @ 1/20/2016) Now 52,166 mi.
*Tesla Model S 61,000 mi
*2011 Leaf 2 bought 4/28/15 @ 24,000ish mi 12 bar (new lizard Dec. 2014 @ 22,273 mi) Now 35,485 mi

lorenfb
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Leaf Number: 416635
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Re: Why the LEAF Gen 2 and not the 220 miles Tesla Model 3?

Tue Sep 12, 2017 5:47 am

GetOffYourGas wrote:
EatsShootsandLeafs wrote:Who knows. Maybe Nissan engineers are just too stupid to come out with an EV that doesn't suffer range loss at 5X (?) the rate of Tesla.


To play devil's advocate here...

The Leaf keeps getting compared to other EVs. Especially Tesla. But the smallest battery Tesla ever made was 2x the size of the largest battery Nissan made (60kWh versus 30kWh respectively). That means that Leafs have at least 2x the number of cycles to travel the same number of miles. On average, it's more like 3x the cycles.

I'm not saying that lack of TMS is not an issue. The Leaf certainly has trouble in hot climates. What I'm getting at is this: we don't know for sure how much of the degradation is due to temperature versus other factors.

Consider only cycle life. If Nissan's batteries are good for 1000 cycles, and the car goes 80 miles per charge, that's only 80k miles. If a Tesla is good for 1000 cycles and goes 200+ miles per charge, that's over 200k miles.

My Leaf is down to about 80% capacity after 45k miles and 5.5 years. If I started with a 40kWh battery rather than a 24kWh battery, would I still see 20% loss in this time? Maybe, maybe not.

Bottom line, I am happy with my Leaf and would be willing to take a risk on a new one. If you don't feel the same, perhaps a Tesla is better for you.


There're others on this forum who think logically and rationally on the issue!

Zythryn
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Re: Why the LEAF Gen 2 and not the 220 miles Tesla Model 3?

Tue Sep 12, 2017 6:12 am

lorenfb wrote:
GetOffYourGas wrote:
EatsShootsandLeafs wrote:Who knows. Maybe Nissan engineers are just too stupid to come out with an EV that doesn't suffer range loss at 5X (?) the rate of Tesla.


To play devil's advocate here...

The Leaf keeps getting compared to other EVs. Especially Tesla. But the smallest battery Tesla ever made was 2x the size of the largest battery Nissan made (60kWh versus 30kWh respectively). That means that Leafs have at least 2x the number of cycles to travel the same number of miles. On average, it's more like 3x the cycles.

I'm not saying that lack of TMS is not an issue. The Leaf certainly has trouble in hot climates. What I'm getting at is this: we don't know for sure how much of the degradation is due to temperature versus other factors.

Consider only cycle life. If Nissan's batteries are good for 1000 cycles, and the car goes 80 miles per charge, that's only 80k miles. If a Tesla is good for 1000 cycles and goes 200+ miles per charge, that's over 200k miles.

My Leaf is down to about 80% capacity after 45k miles and 5.5 years. If I started with a 40kWh battery rather than a 24kWh battery, would I still see 20% loss in this time? Maybe, maybe not.

Bottom line, I am happy with my Leaf and would be willing to take a risk on a new one. If you don't feel the same, perhaps a Tesla is better for you.


There're others on this forum who think logically and rationally on the issue!


It actually is a very good point. The follow up question is, "are the Leafs driven as far as the Tesla vehicles". If you assume the answer is yes, charge cycles should definitely be considered.
I would think that could be accounted for by comparing battery degradation of a Leaf at 50,000 miles with a Tesla at 100,000 miles?
Previous owner of Prius, Volt & Leaf
Current owner of Model S
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lorenfb
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Re: Why the LEAF Gen 2 and not the 220 miles Tesla Model 3?

Tue Sep 12, 2017 6:44 am

Oils4AsphaultOnly wrote:
2. That's great for you! I recently QC'd for 30 mins in 90F ambient and saw a 34F increase (18C) to 123F (9 bars)! Since ambient was still 87F by the time I had parked for the night, my pack temp was still at 118F. It took over 10hrs until the following morning before the pack temp had reduced to 98.6F (still 7 bars).

IF there was a TMS set to cool while charging, then my pack would've spent many HOURS less time at elevated temperatures.

Keep in mind that your 4C increase was above ambient (and most likely during cooler weather too). And it was only for 12-15mins. A higher ambient, means higher peak temps during charging and driving, exactly the times that a TMS would be most effective. We're not looking to keep the battery cooler than ambient. We're trying to limit how far above ambient that the pack temp rises to.


Actually, the ambient was about 90 F when mine was QCed for about 10 - 12 minutes and battery temp only increased by a small amount. Sorry your Leaf is abused, given your knowledge of one of the key factors for battery degradation,
extreme battery temps.

Oils4AsphaultOnly
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Re: Why the LEAF Gen 2 and not the 220 miles Tesla Model 3?

Tue Sep 12, 2017 7:40 am

lorenfb wrote:
Oils4AsphaultOnly wrote:
2. That's great for you! I recently QC'd for 30 mins in 90F ambient and saw a 34F increase (18C) to 123F (9 bars)! Since ambient was still 87F by the time I had parked for the night, my pack temp was still at 118F. It took over 10hrs until the following morning before the pack temp had reduced to 98.6F (still 7 bars).

IF there was a TMS set to cool while charging, then my pack would've spent many HOURS less time at elevated temperatures.

Keep in mind that your 4C increase was above ambient (and most likely during cooler weather too). And it was only for 12-15mins. A higher ambient, means higher peak temps during charging and driving, exactly the times that a TMS would be most effective. We're not looking to keep the battery cooler than ambient. We're trying to limit how far above ambient that the pack temp rises to.


Actually, the ambient was about 90 F when mine was QCed for about 10 - 12 minutes and battery temp only increased by a small amount. Sorry your Leaf is abused, given your knowledge of one of the key factors for battery degradation,
extreme battery temps.


Care to explain what I should've done differently? I QC'd from 30% SOC to 81% SOC that night, because I had a bit more driving to do than you did. Should I have stopped at 60% (~15 mins) so that I end up at home at 2% SOC? Which would've been brilliant planning since I was driving through the mountains and all.

Edit: Frankly, your ambient temp claim leaves me with many questions, since my experience was detailed to the tee and completely different from yours.

Edit: Here's my screen captures for that night and the following morning: https://photos.app.goo.gl/H8O3fTTWVAgbXidB3

Yes I charged close to 100%, because Nissan took away the 80% charge limiter, so I sometimes forget to stop the charge at 7am versus 8am (even though the charge timer is set to stop at 10:40am - setting it at 7am would have the car reach 100% at around 4:30am ... because Nissan says there's NO ISSUE TO FIX).
Last edited by Oils4AsphaultOnly on Tue Sep 12, 2017 9:06 am, edited 1 time in total.
[2013 leaf traded for 2016 leaf S30:
build date: Sep '16 :: purchased: Nov '16
1 May 2017 - 7300 miles & 363 GIDs
6 Sep 2017 - 13k miles & 359 GIDs
26 Oct 2017 - 15.5k miles & 344 GIDs]

User avatar
Nubo
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Re: Why the LEAF Gen 2 and not the 220 miles Tesla Model 3?

Tue Sep 12, 2017 7:49 am

Oils4AsphaultOnly wrote:
Nubo wrote:It might, but the details are important. If the TMS only cools while driving and/or charging, then that leaves a much larger portion of time where the vehicle can still be heat-soaked from ambient temperatures, hot garages, or blistering parking lots. If, on the other hand, it's full-time active cooling, that represents a significant ongoing expenditure of energy 24x7. The sweet-spot of energy cost vs pack longevity vs use cases, might be a lot more complex than first appears.


"It might ..." ?!?!

Are you saying that an active TMS that cools (remember it's the heat that's killing the batteries) only during driving and charging (when there's an additional 2.5 - 5 KW's of heat (charging/regen/discharging efficiency losses) being added to the batteries ABOVE ambient temps won't make a difference towards extending the life of the battery?!

That's like claiming smoking doesn't cause lung cancer since there's also smog in the air. Although it's technically correct, removing the extra heat, much like removing smoking, WILL help.


What I actually said is quoted above. Neither you, nor I, know to what degree a part-time TMS would have mitigated the gen1 LEAF degradation. Drive-time heat is only one contributor to the battery temperature in scorching climates like Phoenix. The early batteries were sub-par. Would part-time TMS have helped? To some degree. Would it have been sufficient to have prevented the premature degradation issue in those climates? I have my doubts. A more durable battery may well have been the more effective way to spend resources to mitigate the problem.

At the time, TMS may have not been the best engineering solution to the LEAF 1 problem. And it doesn't mean TMS is best answer for 2018 LEAF and it doesn't mean TMS is the best approach to all battery chemistries.
I noticed you're still working with polymers.

SageBrush
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Re: Why the LEAF Gen 2 and not the 220 miles Tesla Model 3?

Tue Sep 12, 2017 8:04 am

Zythryn wrote:
lorenfb wrote:
GetOffYourGas wrote:
To play devil's advocate here...

The Leaf keeps getting compared to other EVs. Especially Tesla. But the smallest battery Tesla ever made was 2x the size of the largest battery Nissan made (60kWh versus 30kWh respectively). That means that Leafs have at least 2x the number of cycles to travel the same number of miles. On average, it's more like 3x the cycles.

I'm not saying that lack of TMS is not an issue. The Leaf certainly has trouble in hot climates. What I'm getting at is this: we don't know for sure how much of the degradation is due to temperature versus other factors.

Consider only cycle life. If Nissan's batteries are good for 1000 cycles, and the car goes 80 miles per charge, that's only 80k miles. If a Tesla is good for 1000 cycles and goes 200+ miles per charge, that's over 200k miles.

My Leaf is down to about 80% capacity after 45k miles and 5.5 years. If I started with a 40kWh battery rather than a 24kWh battery, would I still see 20% loss in this time? Maybe, maybe not.

Bottom line, I am happy with my Leaf and would be willing to take a risk on a new one. If you don't feel the same, perhaps a Tesla is better for you.


There're others on this forum who think logically and rationally on the issue!


It actually is a very good point. The follow up question is, "are the Leafs driven as far as the Tesla vehicles". If you assume the answer is yes, charge cycles should definitely be considered.
I would think that could be accounted for by comparing battery degradation of a Leaf at 50,000 miles with a Tesla at 100,000 miles?
It is a hypothetical, although my reading of posts on this forum do not support it. I routinely look at LeafSpy photos from people who come hear with battery degradation questions and calculate the average miles between charges. I don't think I have seen a thread yet where the average miles between charges is greater than 30. GoYG himself reports 45k miles over ~ 2000 days, or about 22 EV miles a day. Now, I don't doubt that Nissan's decision to take away the 80% charge limit was short-sighted in terms of DoD cycling count, but they could have limited "100%" to a lower voltage threshold. So at best this is a relatively minor confounding factor in Nissan's view.
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BrockWI
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Re: Why the LEAF Gen 2 and not the 220 miles Tesla Model 3?

Tue Sep 12, 2017 8:13 am

Along with what GetOffYourGas and others have said about overall charge cycles, and I know this has been brought up before, but when you're cruising at 65 mph you are basically at 1C on the 24 kWh battery, in an hour, it will be dead. Pulling a battery at 1C vs at C/2 is roughly four times the heat generated internally. The same holds true for the charging side, the larger the pack or rather the charge rate compared to the pack size is what matters with internal heat generation. So the larger the pack, given the same load and charge rate, the less heat it will generate internally.

I know I am an outlier living in Green Bay, WI, we just passed 50,000 miles on our 2013 S and we are at 58.77 Ahr, 89 SOH and 89.32 Hx, with no quick chargers in range. Now if we had double the pack size, I would guess we would be less than half that degradation, for a number of reason including primarly pack cycles as well as pack internal heating due to load. I know the life or time on the pack plays in to this and obviously, I am not in Arizona with the car sitting in heat soaked parking lots, instead, I get in to a car that sat 16 hours at -10F or -23C…

I would prefer TMS, but I would be curious to know what it would add to the cost and complexity of the vehicle as well as the range reduction in winter and summer.
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SageBrush
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Re: Why the LEAF Gen 2 and not the 220 miles Tesla Model 3?

Tue Sep 12, 2017 8:24 am

BrockWI wrote: Pulling a battery at 1C vs at C/2 is roughly four times the heat generated internally.
Reference ?
2013 Model 'S' with QC & rear-view camera
Bought off-lease Jan 2017 from N. California with 63.9 Ahr after 22k miles
Car is now enjoying an easy life in Colorado

camasleaf
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Location: Camas, WA

Re: Why the LEAF Gen 2 and not the 220 miles Tesla Model 3?

Tue Sep 12, 2017 8:33 am

SageBrush wrote:
BrockWI wrote: Pulling a battery at 1C vs at C/2 is roughly four times the heat generated internally.
Reference ?


Heat is proportional to the square root of the current. Twice the current means four times the heat.
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