Capacity Loss on 2011-2012 LEAFs

[RegGuheert]

Just wanted to bring up an older post from Tony, which seems to indicate that multiple QCs combined with freeway driving can raise battery temperature by 80F or more. Note that maximum daily temperature in Ashland, OR was 47F that day (March 19, 2012).

:shock: Wow! Thanks for that! I must say that's pretty amazing!

I agree you could never get an 80F rise just by driving around!

 

[Ingineer]

Thanks for all the information, Phil!

Welcome!

You are talking about L2, correct?

Correct.

Thanks for that. Somehow I thought LEAFscan had access to each of the four sensors individually. I guess not. If it somehow combines these, do you know what it does? Average? Peak? Something else?

I can display each of the 4 temps independently, but normally it will display one which is the maximum of the 4. I don't see any point in watching all 4 normally. If one were to go bad, the ECU would set a DTC which would result in a warning TOD (Triangle of Death) on the dash.

I have been using 50 mohm for my calcs. Does anyone have any idea what the resistance will be toward the end of the pack life?

The Battery ECU tracks an internal resistance aging coefficient, but I do not yet have specific knowledge of how it will age.

O.K. That means that something in the pack was above 80F when you parked. How much above 80F is hard to say without a thermal model.

I suspect the cell internals rise, and it takes a bit for them to transfer their heat to the cell cases, which is where the temp probes are.

-Phil

 

[EdmondLeaf]

Not sure about the Nissan pack chemistry, but many batteries are endothermic during discharge (will actually absorb heat) and exothermic during charging. I suspect this is the case for the Leaf pack since you saw a large rise in temperature during charging and a very small rise during driving (which typically pulls more power then charging). This could also explain why they limit the regen to 20kW but will let you have 80kW for accelleration.

My way of recording battery temp is rather primitive, but I observed increase in battery temp while charging, however driving way below speed limit at times, slightly decreased battery temp. Again my recording is primitive, but I thought while driving you may cool battery some, and I was expecting this was due to air flow.

TX people reported few times that multiple QC increases battery temp by 1 bar on average. It was also reported that 9 temp bar gone while driving but this can be either due to temp gradient and/or low range of bar 9 which is just 5F.

 

[Ingineer]

Not sure about the Nissan pack chemistry, but many batteries are endothermic during discharge (will actually absorb heat) and exothermic during charging. I suspect this is the case for the Leaf pack since you saw a large rise in temperature during charging and a very small rise during driving (which typically pulls more power then charging). This could also explain why they limit the regen to 20kW but will let you have 80kW for accelleration.

The DCL (Discharge Current Limit) is usually 110kW IIRC. Regen can exceed 40kW, but the CCL (Charge Current Limit) is usually upwards of 50kW in any event.

OT, but personally I think the regen implementation on the Leaf stinks. I have plans to rectify this issue. =)

-Phil

 

[Stoaty]

OT, but personally I think the regen implementation on the Leaf stinks. I have plans to rectify this issue. =)

Would those plans be only for yourself, or would they include others on this forum (after suitable remuneration, of course)?

 

[palmermd]

OT, but personally I think the regen implementation on the Leaf stinks. I have plans to rectify this issue. =)

-Phil

Get off the forum and get back to work! I want my LeafScan. haha.

 

[Ingineer]

Would those plans be only for yourself, or would they include others on this forum (after suitable remuneration, of course)?

I hope that I can add it as a feature to LEAFSCAN. But that's a future endeavor and OT, so let's save it for another time.

-Phil

 

[opossum]

Word today is that there's a car here right now at one of the Phoenix dealers that lost a second capacity bar. It's not our (drea / opossum, #0500) car, but I predict we will also join the 2-bar club very soon... unfortunately!

Word from Nissan is that this car was deemed to have normal degradation and the pack was not replaced. I suspect the owner has not had the car for 5-10 years. <sigh>

 

[Stoaty]

Word from Nissan is that this car was deemed to have normal degradation and the pack was not replaced.

Let me see if I understand this... losing 2 capacity bars at this stage is "normal degradation"? When was that Leaf purchased? How many miles does it have on it? Any other explanation from Nissan about how this could be "normal degradation"? Is that Leaf expected to have 80% capacity after 5 years (by gaining 1% or so capacity over the next 4 years)?

 

[GaslessInSeattle]

I hope that Nissan understands what a show stopper this is, how owners even in cool climates are looking at this as a test of how they will be treated if early capacity loss hits. Personally, I find it fundamentally unjust for Nissan to say that 20% loss is gradual! LAME!!!!!!!

Word from Nissan is that this car was deemed to have normal degradation and the pack was not replaced.

Let me see if I understand this... losing 2 capacity bars at this stage is "normal degradation"? When was that Leaf purchased? How many miles does it have on it? Any other explanation from Nissan about how this could be "normal degradation"? Is that Leaf expected to have 80% capacity after 5 years (by gaining 1% or so capacity over the next 4 years)?

 

[LEAFfan]

I hope that Nissan understands what a show stopper this is, how owners even in cool climates are looking at this as a test of how they will be treated if early capacity loss hits. Personally, I find it fundamentally unjust for Nissan to say that 20% loss is gradual! LAME!!!!!!!

Word from Nissan is that this car was deemed to have normal degradation and the pack was not replaced.

Let me see if I understand this... losing 2 capacity bars at this stage is "normal degradation"? When was that Leaf purchased? How many miles does it have on it? Any other explanation from Nissan about how this could be "normal degradation"? Is that Leaf expected to have 80% capacity after 5 years (by gaining 1% or so capacity over the next 4 years)?

Losing 2 capacity bars is over 21% loss. If losing 2 bars in a little over a year is gradual, then Nissan has gone insane.

 

[TonyWilliams]

Losing 2 capacity bars is over 21% loss. If losing 2 bars in a little over a year is gradual, then Nissan has gone insane.

This is how legal departments for large corporations in the USA respond. They sure can't say anything else; you will sue them, and they will have handed you the ammo.

I predict a rather ugly outcome, compared to Rav4's that are still running around on original batteries with over 100,000 miles, over 10 years, and still get 100 mile range with a 6.6 kW charger.

 

[Volusiano]

Word today is that there's a car here right now at one of the Phoenix dealers that lost a second capacity bar. It's not our (drea / opossum, #0500) car, but I predict we will also join the 2-bar club very soon... unfortunately!

Word from Nissan is that this car was deemed to have normal degradation and the pack was not replaced. I suspect the owner has not had the car for 5-10 years. <sigh>

You said in an earlier post on this thread (page 67) that there are 2 cars now reported as losing 2 capacity bars. So I do remember seeing the one you mentioned above in an earlier post. But I don't remember seeing a 2nd source of report for 2 capacity bar loss. Can you tell me where on the forum that 2nd report came from? I'd like to read up on the details of that one. Thanks.

 

[cwerdna]

I am no battery/engineer guy, but something must be significantly worse in Arizona versus places like Texas. Humidity and dry air? Payment heating (could there be a difference from asphalt to concrete)? As of yet (knock on wood) no one in Texas has reported battery loss, and, you could easily make the comparison that Texas is mostly similar to Arizona for heat-wise that got early rollouts.

i believe we have reported degradation in TX and CA

Is there another thread ONLY for the tracking of who here on MNL has lost 1 or more capacity bars and their geographic location? I think RegGuheert might've been doing that here or at http://www.mynissanleaf.com/viewtopic.php?f=4&t=8921.." onclick="window.open(this.href);return false;.

Perhaps there should be a dedicated thread for that and minimal/no discussion there, just to keep that thread clean? Or, alternatively someone needs to maintain/compile a list somewhere like a Google Docs spreadsheet, first post of a thread, in the wiki, etc.? It would sure make it easier to keep track of who, where and how much.

 

[RegGuheert]

I think RegGuheert might've been doing that here or at http://www.mynissanleaf.com/viewtopic.php?f=4&t=8921.." onclick="window.open(this.href);return false;.

No, that thread was created to discuss Nissan's response to allow this thread to focus on the details.

Unfortunately the OP here abandoned us long ago. I had gathered up a list in this thread when there were only five, but that is buried somewhere in the middle. I do think Surfingslovak and perhaps others are maintaining lists, but I don't know of a public list.

 

[Stoaty]

Perhaps Nissan recognizes there is a problem and has been purposely putting on the brakes re: sales in the U.S. while they await upcoming improvements in the 2013 Leaf?

 

[leafkabob]

1. Azdre - Reported bar lost mid April to early May, 2012. 17K miles/14 months ownership. Phoenix
2. bturner - May 12, 2012. 13.6K/12 months. Phoenix
3. turbo2ltr - May 18, 2012. 13K/15 months. Phoenix
4. TickTock - May 20, 2012. 12K?/12 months? Phoenix
5. Volusiano - May 20, 2012. 16.5K/12 months. Phoenix
6. Mark13 - May 22, 2012. 15.7K/12 months. Phoenix
7. Leafkabob - May 26, 2012. 9.5K/12 months. Phoenix
8. Cyellen - __________. ___K/14 months. Phoenix
9. RickS - June 10, 2012. 11.3K/13 months. Phoenix

Not reported by owner, but by others:
1. Opossum has reported of two cars in Phoenix that have lost 2 bars.
2. Leafkabob reported a street encounter with a Leaf owner who stated he lost a bar after about a year.

 

[DaveinOlyWA]

I've noticed I can start out with a pack temp of 70, then take a long drive and return home with it reading only a few degrees higher, but still slowly climbing. It will continue to rise once the car is parked (even when inside a building with cool temps and not charging) and sometimes I've seen it get close to 80 before it starts to cool back off. This process takes hours because of the large thermal mass of the pack. If you start charging right away it exacerbates this issue and the temp climbs even higher. Another argument for charging early in the morning!

interesting. i have consistent 279+ readings on my pack after 17,000+ miles and live in a cool climate but thinking i have been helping myself unknowingly since we dont have TOU here, i try to charge when strain on grid is lowest. the "hardest" regular drive on the Leaf is Centrailia which is 32 miles and 90% freeway. usually home around 8:30 but i dont plug in until normally 11 or so. that way it minimizes time sitting at 100% the next morning.

i can see that the lack of temperature information is contributing a great deal to the pack loss issues we are experiencing in hotter climates. wondering how many people who were driving in the early afternoon Sun in Phoenix then parked somewhere and plugged in right away but had time to set a timer for say an hour or two later and still get the charge they needed?

 

[RickS]

Word today is that there's a car here right now at one of the Phoenix dealers that lost a second capacity bar. It's not our (drea / opossum, #0500) car, but I predict we will also join the 2-bar club very soon... unfortunately!

Word from Nissan is that this car was deemed to have normal degradation and the pack was not replaced. I suspect the owner has not had the car for 5-10 years. <sigh>

You said in an earlier post on this thread (page 67) that there are 2 cars now reported as losing 2 capacity bars. So I do remember seeing the one you mentioned above in an earlier post. But I don't remember seeing a 2nd source of report for 2 capacity bar loss. Can you tell me where on the forum that 2nd report came from? I'd like to read up on the details of that one. Thanks.

This was probably me. I visited my dealer on the opposite side of Phoenix from opossum and claimed I thought I had a piece of the cluster burn out. The service advisor said they had another leaf in right then with 22k on it and it was missing two bars. He did ask me how many miles I was getting and my comment was "not add many as I used to".

 

[shrink]

1. Azdre - Reported bar lost mid April to early May, 2012. 17K miles/14 months ownership. Phoenix
2. bturner - May 12, 2012. 13.6K/12 months. Phoenix
3. turbo2ltr - May 18, 2012. 13K/15 months. Phoenix
4. TickTock - May 20, 2012. 12K?/12 months? Phoenix
5. Volusiano - May 20, 2012. 16.5K/12 months. Phoenix
6. Mark13 - May 22, 2012. 15.7K/12 months. Phoenix
7. Leafkabob - May 26, 2012. 9.5K/12 months. Phoenix
8. Cyellen - __________. ___K/14 months. Phoenix
9. RickS - June 10, 2012. 11.3K/13 months. Phoenix

Not reported by owner, but by others:
1. Opossum has reported of two cars in Phoenix that have lost 2 bars.
2. Leafkabob reported a street encounter with a Leaf owner who stated he lost a bar after about a year.

I'm at 10 months/10,000 miles and still have all 12. Will keep you all posted though. I must be on the verge.