WetEV
Posts: 3742
Joined: Fri May 04, 2012 8:25 am
Delivery Date: 16 Feb 2014
Location: Near Seattle, WA

More battery care knowledge is needed. (Leaf Battery 101)

Wed Aug 01, 2012 10:27 am

What I would like to have is a table like this:

If the car does this =Estimate of consequences
---------------------------------------- ---------------------------------------------------------------------------
Temp > 50C (122F) for 24 hours =Void Warranty, probable x.xx% permanent capacity loss per event
(other temperatures and times) =(expected consequences)
...
Very low SOC to car stop =Probable x.xx % permanent capacity loss per event
(Other SOC states) =(expected consequences)

(At this temperature, using normal charge, output power cycle = blah blah blah, and other conditions)
Cycle 70% to 30% =xxxx total full battery cycles
Cycle 100% to 30% =xxxx total full battery cycles
(Other power cycles) =(expected consequences)
Cycle 100% to turtle =xxx total full battery cycles

(at cycle blah% to blah%, other conditions
Quick Charge (once a week) =xxxx total full battery cycles

Other important variables =(expected consequences)

Definitions, like "A full battery cycle is total initial capacity. Going from 60% to 50% ten times is a full battery cycle. 30% capacity loss is the service life end condition."

Without doing extensive testing with cells used in the Leaf, it is hard to see how this table can be made accurate. Only Nissan currently would have access to this kind of information. Releasing this can help the drivers of the Leaf get longer battery lifetimes, and to understand the battery life they actually get.
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

User avatar
Nubo
Posts: 5687
Joined: Fri May 28, 2010 11:01 am
Delivery Date: 31 Oct 2014
Location: Vallejo, CA

Re: More battery care knowledge is needed. (Leaf Battery 101

Wed Aug 01, 2012 3:06 pm

I would love to know how much battery life a full-throttle acceleration consumes, as that is one FUN aspect of this car. :D

I like to rationalize that it's probably inconsequential, since 90KW is less than 4C and it's not being held for more than a few seconds.
I noticed you're still working with polymers.

User avatar
Ingineer
Posts: 2741
Joined: Fri Oct 15, 2010 1:09 pm
Delivery Date: 13 Jul 2011
Leaf Number: 6969
Location: Berkeley, California
Contact: Website

Re: More battery care knowledge is needed. (Leaf Battery 101

Wed Aug 01, 2012 5:59 pm

Nubo wrote:I would love to know how much battery life a full-throttle acceleration consumes, as that is one FUN aspect of this car. :D

I like to rationalize that it's probably inconsequential, since 90KW is less than 4C and it's not being held for more than a few seconds.
I think you are correct Nubo. It's mainly about temperature rise, and driving as hard as I can on a charge doesn't add more than about 10 degrees maximum. Now if you combine that kind of driving with a lot of QC'ing, maybe.

-Phil
Easily Learn Electricity HERE! - - - - Website: http://evseupgrade.com/[/size] - - - - Like us on Facebook: EVSE Upgrade

WetEV
Posts: 3742
Joined: Fri May 04, 2012 8:25 am
Delivery Date: 16 Feb 2014
Location: Near Seattle, WA

Re: More battery care knowledge is needed. (Leaf Battery 101

Fri Aug 03, 2012 10:41 am

Ingineer wrote:
Nubo wrote:I would love to know how much battery life a full-throttle acceleration consumes, as that is one FUN aspect of this car. :D

I like to rationalize that it's probably inconsequential, since 90KW is less than 4C and it's not being held for more than a few seconds.
I think you are correct Nubo. It's mainly about temperature rise, and driving as hard as I can on a charge doesn't add more than about 10 degrees maximum. Now if you combine that kind of driving with a lot of QC'ing, maybe.

-Phil
I'm not so sure if that is true. The internal battery temperature usually can't be measured directly, and may be quite a bit higher than the case temperature. Did you measure the internal battery temperature or case temperature? For a discussion of discharge rates see:

http://www.che.sc.edu/faculty/popov/drb ... /Web38.pdf" onclick="window.open(this.href);return false;

This paper is about a different battery chemistry, and as such doesn't apply directly.

As Nubo suggests, time of discharge is probably important, a few seconds may not matter much, but driving up a mountain at full-throttle (Pikes Peak hill climb) might be a bad idea for the battery life..

Ambient temperature may matter as well, what is a major issue at 40C might not matter much if at all at 20C.
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

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