Capacity Loss on 2011-2012 LEAFs

[surfingslovak]

No, I'm guessing the technology is just not there yet or there are too many other trade-offs... TMS is really the only proper way to go at this juncture.

it just boggles my mind, even the cell balancing was good. it was such a solid test other then ambiant temps... which makes me wonder, why dont they just change the chemistry to be more heat resistant. im sure we would gladly pay whatever more that would cost? im guessing liability at this point if they admit defeat

Yes. The only viable alternative that would come to mind is LiFePO4. This was discussed earlier, and it looks like no major manufacturer is using this chemistry (aside some ramblings about GM and Spark EV). With this particular chemistry, there are concerns about energy density, quick charging and cost, given the current patent situation around LiFePO4 cells. Several recent research papers were mentioned, and an electrolyte tweak, along with anode and cathode composition changes would look like the most likely short-term improvements. This alone might not be enough to sufficiently increase battery life in Phoenix or similar climates. I think that ultimately low battery replacement cost could be the saving grace, and are all waiting for news on that front.

 

[dvlax40]

what about the battery is actually being killed by the heat? is it the electrolyte or the electrodes?

im very interested in the news on the carbon nanotube front. if the electrodes are what the weak link is, then this should be enough to solve the issue

 

[surfingslovak]

what about the battery is actually being killed by the heat? is it the electrolyte or the electrodes?

im very interested in the news on the carbon nanotube front. if the electrodes are what the weak link is, then this should be enough to solve the issue

Based on all the comparative research done earlier, my understanding is that dissolution of the cathode material (manganese) into electrolyte was one of the main factors for capacity loss in LMO batteries. This process is more pronounced at higher temperatures or at higher SOC, and temperature plays greater role than SOC. Please have a look at this NEC study, which was posted by ydnas7 or drees a while ago. NEC is Nissan's partner in the AESC joint venture, which manufactures the cells used in LEAF's battery pack.

Lifetime Extension Technology for Lithium-Ion Secondary Batteries

 

[DaveEV]

It was cool overnight ... the LEAF showed 5 TBs and an OAT of 61F. (We know it's slow to update). Around 09:10 I sat in the car to take some more data with Turbo3's LBM (LEAF Battery Monitor). Couldn't get the BT to connect. Turned the car on/off a few times. It had been charged on EndTimer overnight to 80% by 08:00.

On second power-up ... lost our first capacity bar !

Bummer on losing that bar. I see that your SOC is 75%. Had you driven at all since it finished charging earlier?

On second power-up ... lost our first capacity bar !

It appears that around 83% CAP on the Leaf Battery App is where you are likely to lose the first capacity bar. Have noted this for a couple of other reports.

Seems too coincidental, but that comes out to 55 Ah with the default "100%" rating of 66.2566 Ah.
Edit: Yeah, it is. I see that LEAFer is showing 55.23 Ah when he lost the bar. Maybe the threshold is 55.25 Ah? Davewill's car was also showing just below 55.25 Ah (55.18) when he noticed he lost his bar.

 

[azdre]

Cars bought back by a manufacturer can be resold in all 50 states, but the title of the car is marked as "salvage".

It wasn't marked as salvage, since it wasn't officially bought back under the lemon law. Wouldn't be worth 18K as salvage.

I don't think it's unethical to sell these cars, but I do feel it's unethical not to explain the situation the car was in and what the new buyer can reasonably expect. I would imagine in Nashville that this car won't lose its third bar for a long while, but no one can be certain. I do know the car wasn't driven much in the past four months, and at least in photos it's been sitting with 100% SOC at the dealer. Not good.

The Carfax does show that Nissan repurchased the car, so a new buyer isn't completely blind here, but how would they know what questions to ask unless they had dopne a lot of research on this site? I'm definitely a more cautious, educated consumer than I was two years ago.

I was curious about what happened to RED500, so I pulled the carfax. Looks like it was issued a junk title in Michigan in March of 2013, 5 months after they bought it back. I hope they got some good data off of it that will help the rest of you. In case you don't know/remember this was a 3-bar loser when they bought it back. I think we were actually pretty close to dropping that fourth bar, but luckily my memory of the fiasco is fading fast.

 

[cwerdna]

^^^
Interesting. Any idea if it was in an accident, flood, etc.? Was it always in Nissan's hands or did it end up in the hands of another owner before the junk title?

I wonder what happened to blue 494, the 4 bar loser?

 

[azdre]

^^^
Interesting. Any idea if it was in an accident, flood, etc.? Was it always in Nissan's hands or did it end up in the hands of another owner before the junk title?

Nope went from me --> Nissan --> Junk. I'm assuming it's a pile of scrap now. Not sure if a junk car is resalable in Michigan. The junk classification was actually attached 4 months after it was originally registered in Michigan to Nissan as a 'correction'.

 

[dvlax40]

^^^
Interesting. Any idea if it was in an accident, flood, etc.? Was it always in Nissan's hands or did it end up in the hands of another owner before the junk title?

Nope went from me --> Nissan --> Junk. I'm assuming it's a pile of scrap now. Not sure if a junk car is resalable in Michigan. The junk classification was actually attached 4 months after it was originally registered in Michigan to Nissan as a 'correction'.

sounds like they junked it as soon as they bought it back... some creative accounting or something like that.


as an aside, at no point in the past 24 hours has my battery been under 100 degrees.... how does nissan even think they can survive here?

 

[RegGuheert]

as an aside, at no point in the past 24 hours has my battery been under 100 degrees....

Wow! That's really too bad...

 

[JPWhite]

as an aside, at no point in the past 24 hours has my battery been under 100 degrees....

Wow! That's really too bad...

I've observed that the battery tends to stay about 10 degrees F above ambient even after 'cooling' overnight. It tends to bake. I wonder if the new 2013 lighter pack is designed to promote more rapid dissipation of heat while sitting?

 

[dvlax40]

as an aside, at no point in the past 24 hours has my battery been under 100 degrees....

Wow! That's really too bad...

I've observed that the battery tends to stay about 10 degrees F above ambient even after 'cooling' overnight. It tends to bake. I wonder if the new 2013 lighter pack is designed to promote more rapid dissipation of heat while sitting?

I can say that it doesn't seem that way as my model is the 2013...

 

[TomT]

There is no indication that such is the case. The lighter pack appears to be more the result of repackaging than any attempt to improve convection or cooling. Unless you had two cars side by side for an extended period, it would be hard to draw any conclusions from individual raw numbers since there are so many variables... Since the thermal mass is still about the same, I'd not expect to see much difference, everything else being equal.

I wonder if the new 2013 lighter pack is designed to promote more rapid dissipation of heat while sitting?

 

[RegGuheert]

I've observed that the battery tends to stay about 10 degrees F above ambient even after 'cooling' overnight. It tends to bake.

The cooling system in the LEAF tends to operate like a track-and-hold of ambient temperature. When you are driving, the thermal resistance to ambient is much lower than when sitting. So when you are driving the LEAF, the battery tends to move fairly quickly toward ambient, but when you park, it has much more thermal resistance, so it does not move toward ambient nearly as quickly.

This characteristic is particularly bad in a very hot climate in which you drive home in the peak heat of the day and then park the car overnight (charging during some of that time).

 

[edatoakrun]

...This characteristic is particularly bad in a very hot climate in which you drive home in the peak heat of the day and then park the car overnight (charging during some of that time).

And even worse, if you also fast charge during the day to drive long distances, then park in a hot garage overnight, and repeat...

I was planning a ~3 day ~500 mile trip to the BayLEAFs meeting Tomorrow morning, with a recharge tonight in a ~90 F east bay garage, expecting to get a pretty good reduction in my current battery app reported ~87% capacity (maybe even lose my first bar?) by the time I got back home, due to the current almost-Phoenix-like 100F+ North Valley temperatures.

But I cancelled due to my own personal heat-degradation equation, the reality that I would be in sweltering in Orland right now, with four + hours to kill waiting for the L2 to get me to from the Vacaville DC (and again while driving back on Saturday or Sunday).

BTW, is there any particular reason not to run the LEAF AC for many hours while you are parked and charging on L2?

 

[dvlax40]

BTW, is there any particular reason not to run the LEAF AC for many hours while you are parked and charging on L2?

not that i can see other then increasing the charge time a bit... the battery draw should be a marginal increase in heat.


its just sad to see that there really is little in heat dissipation, even with airflow over the bottom, heat remained constant.

 

[RegGuheert]

BTW, is there any particular reason not to run the LEAF AC for many hours while you are parked and charging on L2?

None that I know of. I've done it when out-and-about running errands on hot days. If you do it while charging, I think it will shut off after two hours, but you can always restart it.

That might help keep the battery cooler or it might dump additional heat in the area near the battery making it hotter.

 

[amelsayed]

What shall I do to add my loss of first CB data to the database?

June 4, 2013; AMElsayed; Vacaville, CA; 31,510; 25 Months; 4213; June 6, 2013; 1135 8813

Tires always @ 44 psi and battery temp indicator usually at 4-5 bars in winter and 5-6 bars in summer.

 

[Joeviocoe]

What shall I do to add my loss of first CB data to the database?

June 4, 2013; AMElsayed; Vacaville, CA; 31,510; 25 Months; 4213; June 6, 2013; 1135 8813

Tires always @ 44 psi and battery temp indicator usually at 4-5 bars in winter and 5-6 bars in summer.

It is actually quite easy for anybody to add themselves to the tracking wiki.
1. Make sure you are logged into MNL..

2. Go to The Tracking Wiki...

3. Go to the section (Loss of one battery capacity bar (15%)) and to the Right of the section title, click "Edit"... (if not there, you're not logged in)...

4. Scroll down slightly to the 2nd "paragraph" of chart data, the set of data that has each line starting with the "pipe ( | )" character, NOT the "exclamation ( ! )"...

5. Select and Copy (Ctrl-C) the ENTIRE paragraph entry of data for the previous data set...

6. Click just ABOVE that paragraph set of data and Paste (Ctrl-V)...

7. You should now have two identical entries...
a) MAKE SURE that there are SPACES ABOVE AND BELOW your pasted entry
b) There must be 12 lines (that start with the "pipe ( | )" character...
c) You MUST have "|- style="background:#ffffff;" valign=top" at the top of your entry...

8. Edit the pasted entry with YOUR own data... and be sure to increment up the incident #

9. Put a summary of what you changed at the bottom of the page... AND CLICK PREVIEW.

10. Once you have verified your Preview looks good, and you have not messed up any entries for other Leaf drivers...
Now, click SAVE.
Done.

***
Note: the URL string on the 4th Line is usually the "Post Subject" link of the user's first post describing the incident. You can find it to right of your Username on the top of the comment/post. Just right-click that link and select "copy link address" or "Copy URL". The 4th line must be the URL <space> unique_username. Just follow the format of previous entries.

Note: PLEASE PLEASE PLEASE, keep the same format for ALL line entries (except for the last line "comments").
Keep all numbers in the same format. (Dates, Mileage, VINs, Claim#s, etc)
Keep the Locations in the same format... and use known city names, not generic areas. Google and Mapquest need to find these automatically.
And please be wary of extra spaces before or after line text.
***

 

[LEAFfan]

as an aside, at no point in the past 24 hours has my battery been under 100 degrees....

Wow! That's really too bad...

I've observed that the battery tends to stay about 10 degrees F above ambient even after 'cooling' overnight. It tends to bake. I wonder if the new 2013 lighter pack is designed to promote more rapid dissipation of heat while sitting?

Mine doesn't stay 10F above ambient overnight. Yesterday, the car was driven almost 70 miles in 110F heat, and it hit 8 TBs during the day (highest TS was 101 with the other two around 99F). By 5AM (parked in garage around 9PM with it at 99F) the TBs were at 6 and highest TS was 91F.
Today, we are supposed to hit 112F and the garage will hit 109-110, then be in the mid-high 80s by 5AM tomorrow.

 

[JeremyW]

and it hit 8 TBs during the day (highest TS was 101 with the other two around 99F)

Interesting, I haven't seen 8 TBs till the sensors were reporting 118F.