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TomT
Posts: 10642
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Leaf Number: 000360
Location: California, now Georgia
Contact: Website

Re: Battery temp management for new leaf

Sat Aug 26, 2017 8:52 pm

I think that the very many of us who had our Leaf batteries crater would argue this "better" point...
edatoakrun wrote:Seven years ago, The LEAF was (and still is) a far superior BEV for most buyers, for having the "better" conductive battery cooling design.
Leaf SL 2011 to 2016, Volt Premier 2016 to 2019, and now:
2019 Model 3; LR, RWD, FSD, 19" Sport Wheels, silver/black; built 3/17/19, delivered 3/29/19.

Stoaty
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Leaf Number: 3871
Location: West Los Angeles

Re: Battery temp management for new leaf

Sat Aug 26, 2017 8:59 pm

edatoakrun wrote:If your LEAF is exceptionally long-lived, and you ever need to put a third ~24 kWh pack in it, you have likely produced about the same adverse environmental impacts of one ~72 kWh pack.
Good point. I can probably drive the Tesla for another 150-200,000 miles, have great range, and equal the environmental impact of 3 Leaf batteries that have much shorter range! Seriously, all the batteries are getting better/cheaper. The 4 year old Tesla is light years ahead of the 6 year old Leaf. Both will be obsolete in a few years (the Leaf a lot sooner), but I will most likely still be driving the Tesla 10 years from now. My weekly 140 mile trips are a breeze now (no need to charge along the way). Plan to take some trips soon that previously would have required my old ICE vehicle and burning gas.
2011 Leaf with 62,000 miles given to Nephew
2013 Tesla Model S85 with 251 miles rated range at full charge
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DaveinOlyWA
Posts: 14149
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Leaf Number: 314199
Location: Olympia, WA
Contact: Website

Re: Battery temp management for new leaf

Sun Aug 27, 2017 9:02 am

SageBrush wrote:
DaveinOlyWA wrote: I can't find anyone paying anywhere near half that
That is what I was telling you in your other thread.
You are self-selecting for people who have agreed to the replacement cost.
how am I self selecting? Do you have info on people forced to pay full price? Because I am not getting that info either and this is not the only source of info here. I had one person who told me that they asked for a deal "a year or more back" and was denied but they had only lost 2 bars.

Is this what you are referring to?
2011 SL; 44,598 miles. 2013 S; 44,840 miles.2016 S30 deceased. 29,413 miles. 2018 S40; 15,000 miles, 478 GIDs, 37.0 kwh 109.81 Ahr , SOH 94.61, Hx 120.15
My Blog; http://daveinolywa.blogspot.com" onclick="window.open(this.href);return false;

lorenfb
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Leaf Number: 416635
Location: SoCal

Re: Battery temp management for new leaf

Sun Aug 27, 2017 10:52 am

edatoakrun wrote: Liquid cooling is only cost effective if If you have a very expensive pack, or in instances when a flammable battery pack (tesla) makes it a safety requirement.

As battery costs continue to fall rapidly, the added expense and efficiency penalty of liquid cooling makes even less sense than it did in the past.

Seven years ago, The LEAF was (and still is) a far superior BEV for most buyers, for having the "better" conductive battery cooling design.
All valid points!

It seems some forget that there're a number of variables that contribute to long term battery degradation,
i.e. temperature (external, charging, use), aging, number of cycles, how deep the battery is discharged, chemistry.
All of these variables have different coefficients of correlation (R) in the model of battery degradation. To assume
that one variable has a greater R and is dominate for all Leaf owners based on their unique environment,
vehicle use, and age is naive. We also know that battery chemistry has improved from the 2011/12 Leafs resulting
in less degradation. So the following statement has merit:
edatoakrun wrote:It would be disappointing if Nissan, in a misguided attempt to satisfy common stupidity, handicaps the Gen two leaf with liquid cooling.
#1 Leaf SL MY 9/13: 74K miles, 48 Ahrs, 5.2 miles/kWh (average), Hx=70, SOH=78, L2 - 100% > 1000, temp < 95F, (DOD) > 20 Ahrs
#2 Leaf SL MY 12/18: 4.5K miles, 115 Ahrs, 5.5 miles/kWh (average), Hx=98, SOH=99, DOD > 20%, temp < 105F

User avatar
Nubo
Posts: 5397
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Location: Vallejo, CA

Re: Battery temp management for new leaf

Sun Aug 27, 2017 2:18 pm

lorenfb wrote:It seems some forget that there're a number of variables that contribute to long term battery degradation,
i.e. temperature (external, charging, use), aging, number of cycles, how deep the battery is discharged, chemistry.
All of these variables have different coefficients of correlation (R) in the model of battery degradation. To assume
that one variable has a greater R and is dominate for all Leaf owners based on their unique environment,
vehicle use, and age is naive.
And this is a valid point, particular when it comes to pack size influencing the depth of the duty cycles. Lack of active cooling may seem like an obvious flaw in LEAF design, but may not be so from an engineering perspective, especially when other considerations and constraints are factored in such as price, reliability, weight, safety, energy efficiency, etc.. These are complex relationships, and the insistence upon a particular engineering feature is, I'd agree, an overly simplistic one if considered an absolute. In the context of one's own relationship to the different sets of compromises (e.g. Tesla vs. Nissan), it may well be spot-on. But not for everyone.

If LEAF sales fall off a cliff in deference to Model 3, then the claims will have proven to be true. Personally I don't expect that to happen. Time will tell.
I noticed you're still working with polymers.

rmay635703
Posts: 533
Joined: Wed Jan 19, 2011 7:43 pm

Re: Battery temp management for new leaf

Sun Aug 27, 2017 3:33 pm

edatoakrun wrote:
Stoaty wrote:
edatoakrun wrote:Seven years ago, The LEAF was (and still is) a far superior BEV for most buyers, for having the "better" conductive battery cooling design.
My "better" 2011 Leaf lost over 30% capacity in 6 years. By contrast, the 2013 Tesla Model S I recently purchased for $43,000 has lost about 5% of original capacity...
From AVTA test results, it looks like the liquid cooled Tesla packs in the B class BEVs, on average required ~30% more Wh per mile driven than the LEAFs, and suffered ~6% pack degradation over one year and ~12k miles.

The B packs degradation rate is somewhat better than The LEAFs (or most all of the other BEVs tested) but how much of the improved retention of capacity was due to active cooling, and how much was due to the reduced number of charge/discharge cycles provided by the B's much larger packs (and also by limiting the drivers' access to a lower percentage of the total pack capacity ?) remains unknown.

Unfortunately, no one (to my knowledge) has ever conducted independent testing of any Tesla BEVs, in order to determine accurate battery degradation rates.

https://avt.inl.gov/vehicle-button/2015 ... es-b-class
My 2013 volt meanwhile uses the same kwhrs to charge today 47,000 miles later as it did new.
Discharges the same 10.3kwhrs today as it did new.

This guys EV range is within the margin of error

https://www.voltstats.net/Stats/Details/1579

Maybe a battery temperature system is a good idea?

WetEV
Posts: 3142
Joined: Fri May 04, 2012 8:25 am
Delivery Date: 16 Feb 2014
Location: Near Seattle, WA

Re: Battery temp management for new leaf

Sun Aug 27, 2017 6:38 pm

rmay635703 wrote:My 2013 volt meanwhile uses the same kwhrs to charge today 47,000 miles later as it did new.
Discharges the same 10.3kwhrs today as it did new.

Maybe a battery temperature system is a good idea?
A thermal management system is a probably good idea in AZ. Near Seattle, maybe not so good. At least that is what studies and experience have shown. No gain in battery life at best, more energy used. Local experience seems to agree. Local Leafs have gotten close to 100k miles before loss of first bar. If loss is linear, 70% loss would come at about 200k miles. Competing similar cars with TMS didn't do as well. Why? They seem to average higher battery temperatures. Or maybe just different battery chemistries.


As for Volt vs Leaf:
Volt has multiple differences from a Leaf.
TMS vs passive cooling.
Volt uses smaller fraction of battery.
Different battery chemistries.

Which factor(s) really matter, and by how much? And how do you know?

Why are you so sure TMS is the only factor?
WetEV
#49
Most everything around here is wet during the rainy season. And the rainy season is long.
2012 Leaf SL Red (Totaled)
2014 Leaf SL Red
2019 eTron Blue

rmay635703
Posts: 533
Joined: Wed Jan 19, 2011 7:43 pm

Re: Battery temp management for new leaf

Mon Aug 28, 2017 2:22 pm

The Volt I linked to is closing in on 400,000 miles with no appreciable degradation.

No volt has gone in for a degraded battery .

So whether it's a low DOD or the thermal management does it matter which if it works?

powersurge
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Location: Long Island, NY

Re: Battery temp management for new leaf

Mon Aug 28, 2017 3:50 pm

This conversation is pointless because you are all talking about totally different cars, for totally different duty cycles.

You cant say that the Leaf sux because it is not as good as the Tesla. The Tesla is a premium luxury car that is bought (excuse me... Leased) by the very rich who don't care how much it costs, or how long it will last. Yes the "premium" battery is huge, and it will take a decade until they deteriorate to a "useless" state. However, Tesla will never be a mainstream car and share driveways with people who drive Hondas and Toyotas.

You cant say that the Leaf sux because it is not as good as the Volt.. The Volt is a HYBRID (with a bigger battery than any hybrid). That car will use the battery only mode as a gimmick, and then go to gasoline operation when it feels like it, to save the battery and not discharge it to any great extent in order to keep the number of discharge cycles low. I personally have a 12 year old Hybrid, and it still works find. So this car doesn't count.

Finally, You cant say that the Leaf sux because of the cooling issues or because of the lower lifetime of its batteries... It is perfectly adequate in a temperate environment. Just so happens that people insist on forcing the Leaf to run in hot desert temperatures that would make an iguana puke. I think the Leaf should never have been sold in those states.... Just like Chevy limited the state in which they sold the Bolt.

What most do not consider is that the Leaf propels the car every second of operation PURELY from battery power. Like a cordless drill. The fact that it can go 100 miles on a charge and gives AC, and heat, and everything else is a minor miracle. If you cannot appreciate that and still complain about the Leaf, then you are probably one of those who thinks their latest IPhone is crap and need to run out to buy the new one when it comes out.

Why don't we just have a regular discussion that If the new Leaf has active cooling, then range will take a hit, just like the use of AC and heat lowers the car's effective range.... Maybe Nissan should make those Desert drivers pay a premium for the active cooling (as an option) and then have lower range. That will shut up the complainers. All of this stuff is science and Physics, and there is no free lunch when you need to balance all of these factors.... It is not the fault of the manufactures that heat is bad for batteries, it is pure science fact that we cannot deny... So... Be smart and don't drive a Leaf where it is hot.

Dooglas
Posts: 283
Joined: Thu Apr 03, 2014 10:08 pm
Delivery Date: 04 Jan 2017
Leaf Number: 314779
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Re: Battery temp management for new leaf

Mon Aug 28, 2017 4:48 pm

powersurge wrote:Why don't we just have a regular discussion that If the new Leaf has active cooling, then range will take a hit, just like the use of AC and heat lowers the car's effective range.....
Well said. And, in the end, after knowing the pros and cons of the design and capabilities of individual EVs - I presume anyone who is half way savvy will choose a vehicle that best meets their needs and situation. Name calling and artificial outrage are hardly a necessary part of that process.
2013 Leaf SV - lease ended, 2016 Leaf S30 - purchased

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