Capacity fade in EVs

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Lumpy12

Member
Joined
Oct 27, 2016
Messages
12
We bought because we keep our cars until they die of old age. So I expect our Bolt to be with us for very many years. I'm not worried about the batteries too much after reading this
http://www.teslacentral.com/worried-about-tesla-battery-degradation-its-23-miles-every-100000-driven

Sure, new technology will come out and better cars will appear, but so what. The Bolt works for us and will suit our needs for many years
 
That article is obviously wrong. Such a slow rate of fade is happy talk. My guess is that users are reporting dash display range not measured range.

The Focus Electric board contained this sort of happy talk three years ago. Now that the cars are racking up time and miles, reality is taking over

http://www.myfocuselectric.com/forum/viewtopic.php?p=26018#p26018

The Bolt battery will do much better due to its size but to believe it won't fade is naive
 
I never said it wont fade. I'm saying I'm not worried about it. But then, I guess I'm naive
 
michael said:
That article is obviously wrong. Such a slow rate of fade is happy talk. My guess is that users are reporting dash display range not measured range.

The Focus Electric board contained this sort of happy talk three years ago. Now that the cars are racking up time and miles, reality is taking over

http://www.myfocuselectric.com/forum/viewtopic.php?p=26018#p26018

The Bolt battery will do much better due to its size but to believe it won't fade is naive
You must be right michael, any study that shows results counter to your beliefs and preconceived notions is obviously wrong.

Because your Focus Electric is showing battery degradation, every other EV will show equal or greater degradation as well?
Advances in battery chemistry and battery management will never be able to improve on 4-5 year old technology?

The best benchmark for the Bolt EV would likely be the Spark EV. The Bolt will likely be better (less degradation) due to:
1) Larger battery pack (less deep cycling, larger thermal mass)
2) Improved battery chemistry

The Bolt battery degradation characteristics are an unknown (in my opinion a good enough reason to lease), but to state flat out that the fade rate will be the same as older technology has no basis. And to call an article wrong that has a large sampling because it is contrary to your experience (or the squeaky wheels on a forum) is rather close minded. Are you suggesting that the authors made up the data? The owners reporting the data lied? What is "wrong" about the article?

And lumpy never said it would NOT fade, only that he was not concerned about the rate of degradation (238 miles offers a huge buffer for daily needs as compared to an 80 mile car).
 
michael said:
When the $7.5K tax incentive goes away, EV sales crater. Sales volume is very small even with this great incentive, without it, vanishingly few will be sold new. Used cars won't become any more valuable.
Not really. I'm sure manufacturers will decrease the price to make up. Then, there is the possibility that the tax credits will continue (by making it a combined pool instead of one pool per OEM).
 
DucRider said:
michael said:
That article is obviously wrong. Such a slow rate of fade is happy talk. My guess is that users are reporting dash display range not measured range.

The Focus Electric board contained this sort of happy talk three years ago. Now that the cars are racking up time and miles, reality is taking over

http://www.myfocuselectric.com/forum/viewtopic.php?p=26018#p26018

The Bolt battery will do much better due to its size but to believe it won't fade is naive
You must be right michael, any study that shows results counter to your beliefs and preconceived notions is obviously wrong.

Because your Focus Electric is showing battery degradation, every other EV will show equal or greater degradation as well?
Advances in battery chemistry and battery management will never be able to improve on 4-5 year old technology?

The best benchmark for the Bolt EV would likely be the Spark EV. The Bolt will likely be better (less degradation) due to:
1) Larger battery pack (less deep cycling, larger thermal mass)
2) Improved battery chemistry

The Bolt battery degradation characteristics are an unknown (in my opinion a good enough reason to lease), but to state flat out that the fade rate will be the same as older technology has no basis. And to call an article wrong that has a large sampling because it is contrary to your experience (or the squeaky wheels on a forum) is rather close minded. Are you suggesting that the authors made up the data? The owners reporting the data lied? What is "wrong" about the article?

And lumpy never said it would NOT fade, only that he was not concerned about the rate of degradation (238 miles offers a huge buffer for daily needs as compared to an 80 mile car).


Good point. Let's look at battery fade in the Spark as measured by Idaho National Laboratory.

https://avt.inl.gov/sites/default/files/pdf/fsev/batterySpark9952.pdf

They tested four Sparks and after only 4000 miles, battery fade was already about 4%. While they haven't yet published fade data after more miles, this fade rate is right in line with pretty much all the batteries they have tested, including those at greater ranges.

Focus batteries were down typically 5% at 4000 miles and 10% at 12,000 miles. These are, incidentally, LG batteries, same brand used in the later Sparks and in the Bolt.

The Tesla happy talk suggests fade of about 10% after 100,000 miles. Even allowing for the difference range (and therefore number of cycles over a distance) there is a huge discrepancy.

Who do you trust? INL or Tesla fan-bois? And how did they determine the reported range? If one reads the Tesla forums, the normal practice is to report the "rated range" on the dash. Who's to say this is correct? My Focus had an ETE display that did not accurately reflect the energy one could extract. It was a poor estimate. Tesla fan-bois trust whatever "Elon" tells them.

While it's true that large batteries fade less over a given number of miles than small batteries (due to fewer cycles), it's also true that "calendar fade" is a significant factor in battery fade. These things will still get tired.

GM warrants 60% remaining battery capacity after 100,000 miles. This is consistent with the specifications for today's LG cells (60% remaining after 500 cycles)

https://www.powerstream.com/p/LG-ICR18650HE2-REV0.pdf

Like I said, I'm getting a Bolt but I have concdrns about fade and I think others would be wise to have the same.
 
My 2013 Leaf, with the improved battery chemistry that came in the month it was built (4/2013), has either 87 or 86% capacity left - I need to check it again. It would have been even less if I had driven and charged it uncaring of outside temps after the first year, and somewhat more if I had known from the first day that I needed to avoid heating the pack. So that's 13-14% loss after just under 4 years.
 
My 2014 Leaf with 28000 miles has 61.8/66 amp hours currently according to Leaf Spy application. That's about 94%. However, I've seen 2 Ah less, about 91%. 3 years old last month, based on when I purchased.
 
Once again, guys, you are relying on the car maker's estimate of battery condition. Bear in mind that the carmaker has an interest in minimizing estimated and reported degradation. That's my criticism of the Tesla estimate.

Like I said, my Focus was estimating about 17.5 kWh usable battery capacity while a test showed just over 15.

INL has tested 2013 Leafs, and typically their results show 15%-17% degradation at 15,000 miles and just over a year in service.

https://avt.inl.gov/sites/default/files/pdf/fsev/batteryLeaf7885.pdf

Which do you believe? Idaho National Laboratory? Or Nissan's on-board estimator?

One other thing...while INL hasn't published a fade test on a Tesla Model S, they did measure the battery on a 85 kWh car and showed useful battery output of about 70 kWh. So there is plenty of margin for Tesla to increase the DOD range as the battery ages and mask fade

https://avt.inl.gov/sites/default/files/pdf/fsev/fact2014teslamodels.pdf
 
Once again, guys, you are relying on the car maker's estimate of battery condition. Bear in mind that the carmaker has an interest in minimizing estimated and reported degradation.

And once again you are making incorrect assumptions. The numbers we are getting are not from Nissan - they have never shared info of this sort. They are from the LeafSpy app, which was developed by Leaf drivers to read the raw data the BMS reports on the pack. Nissan never intended for this data to be user accessible.
 
Anyway, to get back on topic, Nissan seems to have found a way to hijack some Leaf lessees who are interested in the Bolt from GM, at least for now. They have been offering large residual discounts for about two years now, but this month the dealers (who now are the parties we negotiate with for buyouts) have been offered such a huge discount that I can buy my 2013 SV for...<drum roll>... $5000! I know of one women who just bought her 2013 SL for less than $4000.

It looks like we may get to wait until Bolt lease prices get real.
 
LeftieBiker said:
Once again, guys, you are relying on the car maker's estimate of battery condition. Bear in mind that the carmaker has an interest in minimizing estimated and reported degradation.

And once again you are making incorrect assumptions. The numbers we are getting are not from Nissan - they have never shared info of this sort. They are from the LeafSpy app, which was developed by Leaf drivers to read the raw data the BMS reports on the pack. Nissan never intended for this data to be user accessible.


Leaf Spy reads OBD data. These data are the onboard computer's estimate. They ARE Nissan's estimate. Not a test. Not some arm's length third party. Leaf spy doesn't measure or test. It reports what's on the OBD bus. And Nissan puts on that bus what they program the computers to put there. Just in the same way the Ford scanner displayed the data that Ford programmed the OBD bus to display.

What INL reports is what an arm-length government agency determines from a test. What incorrect assumptions have I made?
 
What incorrect assumptions have I made?

That they'd want their own BMS to lie to them, Nissan, when no driver access to the info was assumed. This would prevent Nissan from collecting useful battery data, which they most assuredly do.

Hey, Mods: how about putting this thread in another topic?
 
LeftieBiker said:
What incorrect assumptions have I made?

That they'd want their own BMS to lie to them, Nissan, when no driver access to the info was assumed. This would prevent Nissan from collecting useful battery data, which they most assuredly do.

Hey, Mods: how about putting this thread in another topic?

Done.
 
michael said:
GM warrants 60% remaining battery capacity after 100,000 miles. This is consistent with the specifications for today's LG cells (60% remaining after 500 cycles)

https://www.powerstream.com/p/LG-ICR18650HE2-REV0.pdf

Like I said, I'm getting a Bolt but I have concerns about fade and I think others would be wise to have the same.

It's reasonable to have concerns about the fade, however one difference I think is that the Bolt has 238 miles of range out of the box...err off the car carrier. Even if it degrades to 60% by 100,000 miles you've still got more range (142 miles) than the next longest range, readily affordable EV, the Hyundai Ioniq.

That's in contrast to say a 24 kWh Nissan leaf where at 60% capacity you're down to only 50 miles, at best. I can say with certainty that a Bolt could still fulfill 99% of my needs, although its utility on a road trip would be further reduced from what it already is. With the Leaf, I'd probably be looking at only 40 miles of range in my actual driving conditions, and while it would still be usable it would be approaching the point where range was becoming a serious concern.

That being said, at that point I could just cough up the $6500 for a new battery--hopefully cheaper by then--and I'd be back in business. Incidentally, that is one major reason I wouldn't recommend that anyone buy any used EV besides the Leaf. We know they've been produced in large enough numbers for a battery replacement to be available for a reasonable price. That's not clear with other very low production EVs.
 
LeftieBiker said:
Anyway, to get back on topic, Nissan seems to have found a way to hijack some Leaf lessees who are interested in the Bolt from GM, at least for now. They have been offering large residual discounts for about two years now, but this month the dealers (who now are the parties we negotiate with for buyouts) have been offered such a huge discount that I can buy my 2013 SV for...<drum roll>... $5000! I know of one women who just bought her 2013 SL for less than $4000.

It looks like we may get to wait until Bolt lease prices get real.

I'm not surprised. Leafs are currently selling for $6000 used, and the car dealership has to be making something off of that. Probably they're not going for more than $4000-$5000 at auction anyway. I'm glad they're offering the discounts to the actual drivers of the car so they can keep their own car though.
 
michael said:
Once again, guys, you are relying on the car maker's estimate of battery condition.

I also monitor the energy used to recharge the car. Charging station logs it. So far, at least, that information is consistent with the LeafSpy estimates. Charged a few days ago from 35% SOC to full using 14.7kWh. 240V 30A L2 station. I compute about 92% of capacity.

Note that with LeafSpy full is actually 95% SOC, and stop is at about 2% SOC. The dash meter for state of charge reads 100% when LeafSpy reads 95%.

Now, if I was bored, I'd drive the car until turtle, park by a charging station and run the heat until shutdown. Then record the energy to recharge the car, and compare with the 25.4kWh needed to recharge the battery from empty to full when new. I'm not bored, yet.

michael said:
INL has tested 2013 Leafs, and typically their results show 15%-17% degradation at 15,000 miles and just over a year in service.
Which do you believe? Idaho National Laboratory? Or Nissan's on-board estimator?

My charging station's power meter.

There are a lot of things that can change how fast batteries degrade.
1) Temperature. Coastal WA is much cooler than Arizona. (3 to 4 times faster degradation in Arizona.)
2) Charging and discharging rates. DCQC all the time is fun, but heats up and otherwise degrades your battery.
3) Time spent at full charge. I use the timer to charge right before I leave in the morning. Did the tested cars?
(And more!)

How did the tests use and abuse the Leaf? Without knowing that, I can't compare.
 
There are a lot of things that can change how fast batteries degrade.
1) Temperature. Coastal WA is much cooler than Arizona. (3 to 4 times faster degradation in Arizona.)
2) Charging and discharging rates. DCQC all the time is fun, but heats up and otherwise degrades your battery.
3) Time spent at full charge. I use the timer to charge right before I leave in the morning. Did the tested cars?
(And more!)

How did the tests use and abuse the LEAF? Without knowing that, I can't compare.


In the case of the Leaf, the top three factors are:

* Battery pack temperature

* Battery pack temperature

* Time spent sitting at 100%...in high temperatures, especially.

* Did I mention temperature over long periods of time? Seriously, driving a Leaf in Summer is like having a dog who can't pant.
 
WetEV said:
michael said:
Once again, guys, you are relying on the car maker's estimate of battery condition.

I also monitor the energy used to recharge the car. Charging station logs it. So far, at least, that information is consistent with the LeafSpy estimates. Charged a few days ago from 35% SOC to full using 14.7kWh. 240V 30A L2 station. I compute about 92% of capacity.

Note that with LeafSpy full is actually 95% SOC, and stop is at about 2% SOC. The dash meter for state of charge reads 100% when LeafSpy reads 95%.

Now, if I was bored, I'd drive the car until turtle, park by a charging station and run the heat until shutdown. Then record the energy to recharge the car, and compare with the 25.4kWh needed to recharge the battery from empty to full when new. I'm not bored, yet.

michael said:
INL has tested 2013 Leafs, and typically their results show 15%-17% degradation at 15,000 miles and just over a year in service.
Which do you believe? Idaho National Laboratory? Or Nissan's on-board estimator?

My charging station's power meter.

There are a lot of things that can change how fast batteries degrade.
1) Temperature. Coastal WA is much cooler than Arizona. (3 to 4 times faster degradation in Arizona.)
2) Charging and discharging rates. DCQC all the time is fun, but heats up and otherwise degrades your battery.
3) Time spent at full charge. I use the timer to charge right before I leave in the morning. Did the tested cars?
(And more!)

How did the tests use and abuse the Leaf? Without knowing that, I can't compare.

My measurements on the Focus were performed by running the battery from full charge to stop using the heater, approximately 6 kW, approximately three hours

The INL website describes in detail the way the cars were operated. For example, vehicle 5045 faded 14% over 15,500 miles. The details of it's operation are shown here

https://avt.inl.gov/sites/default/files/pdf/fsev/evop2013Leaf5045EV.pdf

So they actually were very scientific and specific, unlike the Tesla reports.
 
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