SanDust
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Re: Nissan : Leaf’s Battery Pack Should Last As Long As The

Wed Aug 03, 2011 10:48 pm

LKK wrote:If this is true it looks like Nissan's use of a simple air cooled battery thermal management system will pay off big time in terms of cost and reliability over those manufactures using the much more complicated liquid cooled systems.
It's less expensive. And you get to keep a fifth seat. It is, however, hard to see the payoff, unless you think how losing 20% of your capacity over five years is better than losing it over eight years. Heat is certain to kill the battery, so if you live anywhere with hot weather the lack of a TMS will accelerate battery degradation. I could say I hope that isn't the case but it's inevitable so there isn't any point in pretending.

The lack of a TMS was a major reason why I never seriously considered buying. Nissan engineering understands the value of a TMS so I wouldn't be shocked to see one on Gen II.

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evnow
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Re: Nissan : Leaf’s Battery Pack Should Last As Long As The

Wed Aug 03, 2011 11:29 pm

SanDust wrote: The lack of a TMS was a major reason why I never seriously considered buying. Nissan engineering understands the value of a TMS so I wouldn't be shocked to see one on Gen II.
Otherway round - GM really wishes to have next gen LG battery that doesn't need battery cooling so that 5th seat can be added. Renault will also buy some of that, but not before LG improves their battery to be on par with Nissan's.
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SanDust
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Re: Nissan : Leaf’s Battery Pack Should Last As Long As The

Thu Aug 04, 2011 11:22 am

evnow wrote: Otherway round - GM really wishes to have next gen LG battery that doesn't need battery cooling so that 5th seat can be added. Renault will also buy some of that, but not before LG improves their battery to be on par with Nissan's.
You've said you think the Nissan battery is better than the LG Chem battery. Seems to me the chemistry is very similar. What makes you think the Nissan battery is better?

Of course everyone would love to have a battery that didn't need a TMS, but I don't see any current battery chemistry that is practical without it. Nissan is willing to forego the expense of a TMS knowing that this omission will result in replacing some battery packs. This is OK if people are willing to accept a battery warranty that applies to catastrophic failures and not much else, but if they demand a real warranty that guarantees the range then the cost-benefit proposition changes. People who are saying that "it's 120 degrees in my garage and my battery is just fine" are going to be in for a rude shock come year five or six.

AFAIK there isn't a lithium battery on the face of the planet that isn't adversely affected by heat.

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Re: Nissan : Leaf’s Battery Pack Should Last As Long As The

Thu Aug 04, 2011 11:28 am

Given the choice of storing the battery a various SOCs, which is best for battery longevity? :
80%? 50%? 30%?

Lets say you wanted to store the car for a month... Would it be best to set a timer for 80% SOC and just leave it plugged in the whole time?
Or if you could park it at 50% SOC and leave it there, would that be better? (assuming you could plug back in occasionally to recover any charge it lost from just sitting.)

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evnow
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Re: Nissan : Leaf’s Battery Pack Should Last As Long As The

Thu Aug 04, 2011 12:27 pm

SanDust wrote:You've said you think the Nissan battery is better than the LG Chem battery. Seems to me the chemistry is very similar. What makes you think the Nissan battery is better?
They don't need liquid cooling to be usable in an automobile. Try that with an LG battery.
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Stanton
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Re: Nissan : Leaf’s Battery Pack Should Last As Long As The

Thu Aug 04, 2011 12:47 pm

TEG wrote: Lets say you wanted to store the car for a month... Would it be best to set a timer for 80% SOC and just leave it plugged in the whole time?
Or if you could park it at 50% SOC and leave it there, would that be better? (assuming you could plug back in occasionally to recover any charge it lost from just sitting.)
The consensus (in other threads) seems to be: leave it UNPLUGGED at around 50% SOC (or at least less than 80%). That also guards against things like power surges/spikes due to storms, loss of (house) power, etc. You can always check status via CarWings, although Nissan has it would take weeks before you'd see an appreciable loss in capacity (from sitting).
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camasleaf
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Re: Nissan : Leaf’s Battery Pack Should Last As Long As The

Thu Aug 04, 2011 12:49 pm

10000 miles with 326 charges gives an average of 31 miles per charge. Or at 4 miles/kWh about 7.7 kWh per charge. About 30% of the capacity. Maybe the battery does not have time to heat up at short rapid charges. 326 full rapid charges will have, most likely, a different impact.
It is still good to know that rapid charging avery 30-40 miles has little impact on the battery.
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Re: Nissan : Leaf’s Battery Pack Should Last As Long As The

Thu Aug 04, 2011 12:57 pm

TEG wrote:Given the choice of storing the battery a various SOCs, which is best for battery longevity? :
80%? 50%? 30%?

Lets say you wanted to store the car for a month... Would it be best to set a timer for 80% SOC and just leave it plugged in the whole time?
Or if you could park it at 50% SOC and leave it there, would that be better? (assuming you could plug back in occasionally to recover any charge it lost from just sitting.)
Start at ~30% and set the timer to charge to 80% but only for one hour per week. Just to make it fun ;)
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TEG
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Re: Nissan : Leaf’s Battery Pack Should Last As Long As The

Thu Aug 04, 2011 1:04 pm

Stanton wrote:
TEG wrote: Lets say you wanted to store the car for a month... Would it be best to set a timer for 80% SOC and just leave it plugged in the whole time?
Or if you could park it at 50% SOC and leave it there, would that be better? (assuming you could plug back in occasionally to recover any charge it lost from just sitting.)
The consensus (in other threads) seems to be: leave it UNPLUGGED at around 50% SOC (or at least less than 80%). That also guards against things like power surges/spikes due to storms, loss of (house) power, etc. You can always check status via CarWings, although Nissan has it would take weeks before you'd see an appreciable loss in capacity (from sitting).
Thanks. Another angle, is I start at 80% each morning, drive to work, get there at about 50%, have no place to plug in, so it sits for 8+ hours a day at 50%, gets run down to close to 20% on the way back home, and starts a slow charge through the night.
So, on average it stays around 50%, and is basically at 50% the whole (hot) part of the day. Probably not too bad. I feel a little bad about dragging it down to nearly 20% on a daily basis, but such is life with a slightly long commute.

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mwalsh
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Re: Nissan : Leaf’s Battery Pack Should Last As Long As The

Thu Aug 04, 2011 1:27 pm

TEG wrote:Thanks. Another angle, is I start at 80% each morning, drive to work, get there at about 50%, have no place to plug in, so it sits for 8+ hours a day at 50%, gets run down to close to 20% on the way back home, and starts a slow charge through the night.
So, on average it stays around 50%, and is basically at 50% the whole (hot) part of the day. Probably not too bad. I feel a little bad about dragging it down to nearly 20% on a daily basis, but such is life with a slightly long commute.
I do more or less the same thing. Though I start at 100% and it sits at about 60% for the bulk of the day, getting me home with approximately 25% left (will know just how much with more accuracy once I get my SOC meter built).
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