Some Leaf Owners Experience Early Capacity Loss

[Herm]

BTW, I admit that I'm no specialist in Volt cooling system, but I had a feeling that it is just a loop through radiator, so it will not actually cool the battery if ambient temperature is high. Or will it actually run the AC?

Yes it actually runs the AC, the Ford Escape Hybrid does so as well.

I think Nissan should have made 80% charging level the default always, if you want a 100% charge just hit the override button and have some appropriate text pop up (skull and bones, poison ugh face?).

 

[scottf200]

Well, I have to agree, that the thermal management in Volt might be better, but I don't see how it relates to long term storage... Well, maybe very marginally
Long term storage at any SOC is bad in extreme heat, and Volt's system only manages heat until 75% of full, at which point it will be the same deal as leaf. So, if you compare Volt and Leaf when you charge them to 100% and leave in the middle of the desert for a month, Volt will perform slightly better by discharging the battery to 75%. If you leave the Leaf at 75% or lower, in the middle of the desert, Leaf will behave exactly as Volt... doing nothing.

Well, how about this. You and I park our Leafs in Phoenix for a year. You will be at 100%, and I will be at 75%. We reconvene in one year, and compare notes. I hope you can afford the repair bill, ignorance tends to be expensive, at least in my experience.

I think all the manufacturers know that some owners situations (long days in extremely hot parking lots) will not be good for the batteries. Here is even a quote from a GM engineer that points out the Volt may NOT be right for everyone and every situation.

Here’s a quote from Volt Chief Engineer Andrew Farah relevant to this discussion:

One disappointment is that the Volt and other Lithium-ion battery-powered electric vehicles may not be viable in hotter climates, such as some states in the American Southwest. Despite the fact that Volts will be sold in these states, performance may be significantly undermined due to the heat. Volt Chief Engineer Andrew Farah describes, “The Volt may not be right for everyone. If you live in the Southwest, depending on how you use your car, the Volt might not be right for you.”

http://www.dailytech.com/Chevy+Volt...ut+Otherwise+is+Looking+Good/article16969.htm

 

[thankyouOB]

i have no capacity loss that I can see. I dont have the SOC meter.

I do notice that more commonly, I have 6 bars on the battery heat side than 5.
I began to notice this last week. It has happened twice after work, where I park in a huge underground garage that is about 75 degrees constant.
I first noticed it after charging to 100% via trickle.
the next time to 90% or so.

I have to do more monitoring to check frequency and charging association.

 

[thankyouOB]

so, now I have two issues and questions for the gang:
--i can use trickle or L2 at work. does it matter for battery health. I park for 8 hours and either mode will get me to 80% for the trip home.
I can use L2 and not charge at home but that would run my battery down to 2 bars when I get to work.
--i have always used the start and end times, so I charge beginning when I plug in, and charge the vast majority of times to 80%.
would battery life be extended if I begin to use just the end timer, so I dont hold the battery at 80% for several hours on work days?

thanks.

 

[LEAFfan]

so, now I have two issues and questions for the gang:
--i can use trickle or L2 at work. does it matter for battery health. I park for 8 hours and either mode will get me to 80% for the trip home.
I can use L2 and not charge at home but that would run my battery down to 2 bars when I get to work.
--i have always used the start and end times, so I charge beginning when I plug in, and charge the vast majority of times to 80%.
would battery life be extended if I begin to use just the end timer, so I dont hold the battery at 80% for several hours on work days?
thanks.

I would use the 120V/trickle so it will free up the L2s for others that may need to use those. Leaving the car for a day at work with 80% is good. Even leaving it at 100% for a few hours isn't going to hurt either.

 

[thankyouOB]

I would use the 120V/trickle so it will free up the L2s for others that may need to use those. Leaving the car at 80% is good. Even leaving it at 100% for a few hours isn't going to hurt either.

i am the only user and there are a dozen blinks.

 

[kmp647]

In the blog I noticed he pasted together statement from 2 people and made it look like 1 person said it

Not good. I will be watching my words here much more carefully.

I don't like being mis- quoted and I rather not be quoted at all!

 

[planet4ever]

so, now I have two issues and questions for the gang:
--i can use trickle or L2 at work. does it matter for battery health.
--would battery life be extended if I begin to use just the end timer, so I don't hold the battery at 80% for several hours on work days?

My personal reaction is that L1 and L2 are both very slow charges (compared, for example, with regen), and which one you use will have no effect on battery health. L1 is less efficient in the LEAF, so uses a bit more electricity to get the same charge. If you care about world energy use or cost to employer, L2 will have a miniscule, but positive, advantage.

I also don't think it is hard on the battery to maintain the charge at 80%, even for weeks at a time, let alone the hours that you are talking about. If you were charging to 100% that might be a different story.

Ray

 

[thankyouOB]

thanks, Ray.

 

[ChargedUp]

In the blog I noticed he pasted together statement from 2 people and made it look like 1 person said it

Not good. I will be watching my words here much more carefully.
I don't like being mis- quoted and I rather not be quoted at all!

KMP if I "pasted together statement from 2 people and made it look like 1 person said it"
it was completely unintended. If you will indicate where I have done that I will be happy to correct it.

If you feel that I have misquoted you, I would also like to correct that or at least understand how you feel you were misquoted.

It never occured to me that someone posting comments in a public forum would not want
those comments to be reposted in another public forum.

Marc Lee

 

[TRONZ]

It never occured to me that someone posting comments in a public forum would not want those comments to be reposted in another public forum.

Marc Lee

Well stepping back a bit, I think the real question is why would someone go to such lengths to highlight what are clearly outliers in LEAF ownership. Saying it is to "educate" owners and potential owners could be taken two very different ways.

 

[Herm]

If it works out that Leafs in Arizona suffer early battery degradation then it will be big news, we are seeing some glimmers of hints popping up now. Its big news.

 

[TRONZ]

Actually, I think it is certain that a few LEAFs in very hot regions are showing some degradation but something so anticipated is hardly big news. We have been talking about this likelihood for over a year and now we probably have our first data points. We also have a LEAF approaching 40K miles with everything nominal. Pick your "news".

I am actually amazed that LEAF packs can sit all day inches from asphalt that can fry an egg and get very little degradation. Owner patterns will become very interesting.

 

[SanDust]

Actually, I think it is certain that a few LEAFs in very hot regions are showing some degradation but something so anticipated is hardly big news.

So anticipated? If memory serves me correctly, when I suggested this would happen you and others attacked the idea as FUD. :lol:

 

[TRONZ]

So anticipated? If memory serves me correctly, when I suggested this would happen you and others attacked the idea as FUD. :lol:

Geeeee... an EV in the desert will get battery degradation first. Your hardly the "genius" that came up with that one. We will be sure to give you credit for the sunrise tomorrow if it makes you feel better. :roll:

 

[Stoaty]

This "hint" that heat may be more of a problem than Nissan led us to believe means I will switch to 70% charging in the summer. I will arrive at work with a 50% charge, leave my car in the hot sun in the San Fernando valley all day (no shaded parking, unfortunately), and get home with a 30% charge. Overkill compared to 80% charging? Perhaps, but it is easy for me to make this change and there are no downsides.

 

[surfingslovak]

This "hint" that heat may be more of a problem than Nissan led us to believe means I will switch to 70% charging in the summer. I will arrive at work with a 50% charge, leave my car in the hot sun in the San Fernando valley all day (no shaded parking, unfortunately), and get home with a 30% charge. Overkill compared to 80% charging? Perhaps, but it is easy for me to make this change and there are no downsides.

Where is the "Like" button? MNL really needs one!

Although this might sound like a very conservative choice to some owners, please keep in mind that it depends on your objective. Some owners would like to keep the car for a while. Even if battery prices fell precipitously, pack reconditioning or complete replacement might still be a significant expense down the road. It's not a bad idea to treat the pack conservatively, if your usage pattern allows it.

However, if you would like to drive a Leaf like any other car or plan to replace it in two or three years, then more power to you. The AESC batteries Nissan is using seem to be more robust than many people, myself included, originally anticipated. I would just be a bit more mindful of high state of charge during hot summer months. The easiest solution there is to park the car in the shade or underground, which will allow the pack to stay cooler. Selecting 80% as your default charge level when it's hot out will help too.

If you are not going to drive for more than a week, unplug the car, and make sure that it's not fully charged. Ideally, the battery gauge should display five or six bars for storage. The easiest way to lose some charge, is to turn the climate control on remotely. This works great, and the only downside I can see is a lower CarWings ranking ;-)

 

[LEAFfan]

Again, there's no proof that AZ heat has caused any of the latest problems. Some of you posters are jumping to conclusions. TickTock's and my car sat for almost 3 months in the CA port. THAT is more likely why we have a problem with our packs. The other one let it sit with 100% charges and had multiple 'top offs'. Anyone that does this with their LEAF has a good chance of having battery pack problems no matter what state their car is located. It would be prudent to save your conclusions until after more evidence is obtained.

 

[Stoaty]

It would be prudent to save your conclusions until after more evidence is obtained.

Actually, it is prudent to minimize SOC, especially at high temperatures, until evidence is obtained that this doesn't make any difference. The reports in this thread serve as a reminder of that principle. I would like to get maximal battery life, not average.

 

[surfingslovak]

It would be prudent to save your conclusions until after more evidence is obtained.

Actually, it is prudent to minimize SOC, especially at high temperatures, until evidence is obtained that this doesn't make any difference. The reports in this thread serve as a reminder of that principle. I would like to get maximal battery life, not average.

Stoaty is right. Initially, when it was not clear how well the Leaf will do in the field, even Nissan was careful with their recommendations, and said to use QC sparingly. We can only make educated guesses about the recent reports from AZ, but their number and their geographic clustering is a bit disconcerting, wouldn't you say? There are four known cases of below average battery performance in and around Phoenix, an additional one in Austin, and another one in LA. We don't know much more than that, except that these owners all live south of the 34th parallel.

Without wanting to speculate, I would like to point out that lithium-manganese cells are generally regarded to be more temperature sensitive, and they degrade faster in hot environments than lithium-cobalt or lithium-iron-phosphate. If you examine reports on generic lithium-manganese cells and look at their properties, it's obvious that much can be gained from lowering the SOC, especially at higher temperatures. We don't know how Nissan has customized their AESC cells, and they are not releasing much information. Be it as it may, it's unlikely that this principle does not apply to these batteries. Owners that wish to take a conservative approach can either try to find a cool parking spot or maintain a lower SOC during hot summer months.

Note that the same thing can be said of cycling losses, but as others have pointed out, and as the data from some owners clearly indicates, we don't have to worry about this as much as previously thought. As you said, once we have more data, we can adjust our behavior accordingly. Until then, it's not wrong to proceed with caution. The issues that recently came to light are a reminder of the risk early adopters are taking. I think most of us are here because we would like to support this technology. Let's not lose sight of that, and let disagreements be a distraction. I hope that you, TickTock, and other affected owners can get a satisfactory resolution. Hopefully, we all will learn a thing or two from this.