Capacity Loss on 2011-2012 LEAFs

[Randy]

Can we start a list like this people in hot climates that have similar usage stats (i.e. age/mileage) that have NOT lost capacity yet?
Just to get feeling for the x in 20 out of x.
I suspect it is a systematic thing, i.e. a consequence of the heat acting on the battery chemistry, but maybe not (...wishful thinking...)

I think a more useful list would be to record for as many people as possible:

--Gid count at 100% charge
--Length of ownership
--Odometer mileage
--Geographic location

This would include everyone we can get a measurement for, whether they have lost a capacity bar or not.

I started such a thread yesterday so we can start to gather data...

http://www.mynissanleaf.com/viewtopic.php?f=27&t=9253" onclick="window.open(this.href);return false;


Randy

 

[EdmondLeaf]

In response to a question:

The car is garaged. It is rarely out of the garage for more than 2-3 hrs at a time.
Its primarily used to pick up and drop of our son at school, trips to the grocery store
etc. Our garage door is insulated and today for example its 102F outside
and 85F in the garage.

Might be interesting to get a thermometer and check the "usual suspects".

That is exactly what I did, I did not look very far:this is temp 1 ft above the close by road, ambient temp was 100F
6/24/2012 15:45 125.064F
6/24/2012 16:00 126.289F
6/24/2012 16:15 125.771F
6/24/2012 16:30 125.692F
6/24/2012 16:45 124.363F
6/24/2012 17:00 125.064F

Do not expose a vehicle to ambient temperatures above 120F (49C) for over 24 hours.

 

[thankyouOB]

if you lose one battery bar, how much loss of capacity is that - 1/12 or 8.5%?

From the Nissan data its actually 15%

how does that work, if you lose on bar?

 

[Stoaty]

how does that work, if you lose one bar?

See the Leaf Wiki "Battery Capacity Behavior": http://www.mynissanleaf.com/wiki/index.php?title=Battery,_Charging_System#Battery" onclick="window.open(this.href);return false;

It's from the Leaf service manual.

 

[TonyWilliams]

Limit should be set by manufacturer disabling vehicle when battery temp is close to danger zone, because there is no way to control or know what actual battery temp really is.

Nissan knows the exact temperature, I believe they start to dial back the power at 10 bars.. probably complete shutdown at 11 bars and a star trek phaser overload alarm starts blaring at 12 bars. If you listen carefully you might hear the cells venting.

Sorry, not true. I quick charged the LEAF one week ago with 10 battery temperature bars, and it did not do any of the things you suggest.

The battery actually lost temperature bars while driving in 60F ambient heat over the next 85 miles at 60 mph.

 

[Herm]

Sorry, not true. I quick charged the LEAF one week ago with 10 battery temperature bars, and it did not do any of the things you suggest.

Good to hear, do you know what to do if you hear that overloaded phaser sound?.. did you lose any power bubbles at 10?

 

[RegGuheert]

It's from the Leaf service manual.

It's not in the one I downloaded in March 2012. My MWI service manual says it is an April 2011 revision.

Does anyone know what revision contained the capacity bar table shown in the Wiki?

 

[Carcus]

In response to a question:

The car is garaged. It is rarely out of the garage for more than 2-3 hrs at a time.
Its primarily used to pick up and drop of our son at school, trips to the grocery store
etc. Our garage door is insulated and today for example its 102F outside
and 85F in the garage.

Might be interesting to get a thermometer and check the "usual suspects".

That is exactly what I did, I did not look very far:this is temp 1 ft above the close by road, ambient temp was 100F
6/24/2012 15:45 125.064F
6/24/2012 16:00 126.289F
6/24/2012 16:15 125.771F
6/24/2012 16:30 125.692F
6/24/2012 16:45 124.363F
6/24/2012 17:00 125.064F

Do not expose a vehicle to ambient temperatures above 120F (49C) for over 24 hours.

... and so it's not hard to imagine that a Leaf parked at a mall in Phoenix on a "nice" summer day could be sitting in a bath of 140 + deg air. Well into the "red bar" zone of the Leaf's battery temp gauge.
Kind of makes you wonder about the details of the Leaf battery temp monitoring system.
-- how many temp sensors are involved (just one, or are there several)?
--where is it (are they) placed (i.e. top of the pack, in between cells, bottom of the pack)?

 

[thankyouOB]

how does that work, if you lose one bar?

See the Leaf Wiki "Battery Capacity Behavior": http://www.mynissanleaf.com/wiki/index.php?title=Battery,_Charging_System#Battery" onclick="window.open(this.href);return false;

It's from the Leaf service manual.

THE LOVE MY LEAF charging table shows loss of 8.5% not 15%.
I am not sure where you are getting this data.

Can someone please explain why the loss of one battery capacity bar due to degradation of the battery -- not usage on a single occasion -- equals loss of 15% of available power reserve?

 

[DaveEV]

--how many temp sensors are involved (just one, or are there several)?
--where is it (are they) placed (i.e. top of the pack, in between cells, bottom of the pack)?

There are multiple (4 I believe Phil has said - details are in his LEAFSCAN thread somewhere and probably elsewhere) and they are distributed through the pack and appear to be designed to measure core pack temperature.

The modules themselves will conduct heat very well given their high metal content so the temperature probes should provide an accurate picture of battery pack temperature.

See the Leaf Wiki "Battery Capacity Behavior": http://www.mynissanleaf.com/wiki/index.php?title=Battery,_Charging_System#Battery" onclick="window.open(this.href);return false;

It's from the Leaf service manual.

THE LOVE MY LEAF charging table shows loss of 8.5% not 15%.
I am not sure where you are getting this data.

You are mixing up the battery SOC meter with battery capacity meter. Tony's charts do not display any information on the battery capacity meter.

 

[thankyouOB]

You are mixing up the battery SOC meter with battery capacity meter. Tony's charts do not display any information on the battery capacity meter.

thanks!!

 

[Boomer23]

how does that work, if you lose one bar?

See the Leaf Wiki "Battery Capacity Behavior": http://www.mynissanleaf.com/wiki/index.php?title=Battery,_Charging_System#Battery" onclick="window.open(this.href);return false;

It's from the Leaf service manual.

Note that there's an important error on the LEAF Wiki list of capacity bar loss owners' locations. Leafkabob, number 16 on the list, is shown as located in Orange County, CA, but his location is actually Phoenix.

 

[klapauzius]

Can someone please explain why the loss of one battery capacity bar due to degradation of the battery -- not usage on a single occasion -- equals loss of 15% of available power reserve?

If it was linear, i.e. the top bar would represent a loss of 1/12 of capacity, many more
people would report capacity loss by now (alerted by the missing bar).
That is undesirable from a psychological point of view (i.e. as Nissan sees it, I assume).

If they had put the top bar at 25 % loss, no one would report missing bars by now and
everyone would be happy :lol:

Maybe there was some well meaning engineering involved in trying to linearize the non-linear capacity over time curve, e.g. equal amounts of bars are lost over equal amounts of time....

 

[JPWhite]

Maybe there was some well meaning engineering involved in trying to linearize the non-linear capacity over time curve, e.g. equal amounts of bars are lost over equal amounts of time....

That would be nice of them, but to be honest I don't think they expected these type losses so early in the battery life. My guess, and that's all it is, is that they figured the worst case scenario is 5% loss per year, so 15% will get us to the end of the lease period without showing a loss of a bar. Thus making it more valuable and easier to resell with no money spent on the returned LEAF. Average loss is expected to be 2-3% per year on average, so the majority of LEAF's would come off lease with all capacity bars showing. I believe Steve Marsh has reported less than 2% capacity loss after 1 year and 40,000+ miles in the cooler climes of the Pacific Northwest.

Pheonix temps seem to be bad for the LEAF, unless something else is going on.

 

[ravi100]

In response to an earlier question, our driveway is only one car wide so we never park on the driveway
because the 2nd car cant get through. Like I said previously the car has been garaged consistently.

 

[FairwoodRed]

Nissan knows the exact temperature, I believe they start to dial back the power at 10 bars.. probably complete shutdown at 11 bars and a star trek phaser overload alarm starts blaring at 12 bars. If you listen carefully you might hear the cells venting.

Sorry, not true. I quick charged the LEAF one week ago with 10 battery temperature bars, and it did not do any of the things you suggest.

The battery actually lost temperature bars while driving in 60F ambient heat over the next 85 miles at 60 mph.

Tony,

While I don’t have your expertise, I must disagree with you on this.

My experience was that I watched my traction and regen bubbles disappear (single bubble vs double bubble) during a day trip to Portland last weekend. My temp bars were at 10 when I completed a QC and I saw the missing bubbles. Over the next half hour, I saw the bubbles slowly come back and in the next half hour, the temp dropped to the 9th bar. I clearly saw the car dial back the power and I believe it was in response to high pack temp. Perhaps you were at the low end of 10 and I was at the high end?

Interesting thing was that I lost more regen bubbles and they came back later than the traction bubbles.

 

[Stoaty]

Note that there's an important error on the LEAF Wiki list of capacity bar loss owners' locations. Leafkabob, number 16 on the list, is shown as located in Orange County, CA, but his location is actually Phoenix.

Corrected the Wiki, thanks (I was wondering how someone in CA lost a capacity bar without living in Palm Springs).

 

[leafkabob]

how does that work, if you lose one bar?

See the Leaf Wiki "Battery Capacity Behavior": http://www.mynissanleaf.com/wiki/index.php?title=Battery,_Charging_System#Battery" onclick="window.open(this.href);return false;

It's from the Leaf service manual.

Note that there's an important error on the LEAF Wiki list of capacity bar loss owners' locations. Leafkabob, number 16 on the list, is shown as located in Orange County, CA, but his location is actually Phoenix.

Boomer, I noticed that also. I was kind of excited to think that everyone else could take over updating the list. After I looked at it and saw that error, I decided to continue to keep my own list.

 

[tbleakne]

Might be interesting to get a thermometer and check the "usual suspects".

That is exactly what I did, I did not look very far:this is temp 1 ft above the close by road, ambient temp was 100F
6/24/2012 15:45 125.064F
6/24/2012 16:00 126.289F
6/24/2012 16:15 125.771F
6/24/2012 16:30 125.692F
6/24/2012 16:45 124.363F
6/24/2012 17:00 125.064F

I also may have seen this effect, where my car picks up the next temperature bar while parked over hot, unshaded pavement. If there is no shaded pavement to be found, an insulated blanket placed under the middle and rear of the car, with a topside of foil with low emissivity, might be effective in blocking a substantial portion of this heat transfer to the battery. Not necessarily a practical suggestion, but possibly worth considering.

 

[planet4ever]

It's from the Leaf service manual.

It's not in the one I downloaded in March 2012. My MWI service manual says it is an April 2011 revision. Does anyone know what revision contained the capacity bar table shown in the Wiki?

I've been wondering about that, too. I haven't been able to find it in my April 2011 revision.I see two Power Meter (bubble gauge) charts, the battery temperature gauge chart, the (old) available charge gauge chart, and pages and pages of "half full" pictures showing how the battery capacity interacts with the other gauges, but no battery capacity gauge numbers.

Ray