Capacity Loss on 2011-2012 LEAFs

[dhanson865]

I'm assuming I will end up operating my used leaf' in the predicted the 5-10 year capacity region.
say 50 % capacity. Will that mean much lower charge efficiency ( same power in-less power out ) ??? :?: :?: :?:

What do you guys with 50-75K miles see in this respect ?

does the battery become that much less efficient or does it just finish charging faster?

 

[dgpcolorado]

Are we all now pretty clear that losing 1 bar in the 20 -30K range is pretty normal for most users in moderate climates, who don't overheat/overcharge ? ...

In general I'm going to say "no". Mileage has much less to do with battery capacity loss than simple heat + age. It is true that charge cycles and heating while driving — both related to mileage — will have some impact, but it seems to be fairly small compared to degradation due to overall heat and age. An obvious example was TaylorSFGuy who went 78,600 miles before losing the first capacity bar.

 

[abasile]

I'm in a cooler climate on a mountain, but my 2011 LEAF battery had a fair amount of exposure to heat from commuting down into the much warmer valley below, for almost two years. My LEAF lost the first bar at about 41K miles and at 52K miles and counting, the capacity loss is slower now that I don't have that commute. The regen has gotten somewhat worse with battery age, or perhaps because of firmware updates, but other than that and the reduced range, nothing else appears to have changed.

My intention is to keep driving this LEAF until we can make a good cash deal on a used Tesla X (or maybe S) with AWD (dual motors!), larger battery, and of course Supercharger access. That might be at least another couple of years away. Even then, we'll probably keep the LEAF as a second EV.

 

[mwalsh]

does the battery become that much less efficient or does it just finish charging faster?

Thankfully, no. With the possible exception of a small reduction in regenerative capture.

 

[DaveEV]

I'm assuming I will end up operating my used leaf' in the predicted the 5-10 year capacity region.
say 50 % capacity. Will that mean much lower charge efficiency ( same power in-less power out ) ??? :?: :?: :?:

What do you guys with 50-75K miles see in this respect ?

does the battery become that much less efficient or does it just finish charging faster?

At L2 charging speeds, internal resistance is low enough that there is no measurable difference in charging efficiency. At QC charging speeds, the rise in internal resistance simply means that the car charges slower as it hits the BMS's maximum allowable cell voltages sooner of about 4.1V / cell. But still, internal resistance is low enough that not a significant difference in energy is lost to heat in the pack.

You do lose efficiency due to reduced regen the car allows, though. For example, just after having lost 2 bars, with my pack in the 70-72F range, I only get about 15 kW of regen maximum at 75-80%. When the car was still in it's first year, 25-30 kW was possible.

I really wish that Nissan would loosen up the allowed regen - it's clear that the battery can take more (cell voltages remain well below 4.1V) and the reduction in regen above and below appx 20 mph really makes a difference for me as I live on a 300 ft hill that I descend every day. Unless there is no traffic behind me and I am able keep my speeds down (and thus regen up), I currently lose about half the regen I would otherwise be able to get. For those days when I start off at 100%, I easily lose 10% efficiency on my commute.

 

[Pipcecil]

I'm assuming I will end up operating my used leaf' in the predicted the 5-10 year capacity region.
say 50 % capacity. Will that mean much lower charge efficiency ( same power in-less power out ) ??? :?: :?: :?:

What do you guys with 50-75K miles see in this respect ?

does the battery become that much less efficient or does it just finish charging faster?

At L2 charging speeds, internal resistance is low enough that there is no measurable difference in charging efficiency. At QC charging speeds, the rise in internal resistance simply means that the car charges slower as it hits the BMS's maximum allowable cell voltages sooner of about 4.1V / cell. But still, internal resistance is low enough that not a significant difference in energy is lost to heat in the pack.

You do lose efficiency due to reduced regen the car allows, though. For example, just after having lost 2 bars, with my pack in the 70-72F range, I only get about 15 kW of regen maximum at 75-80%. When the car was still in it's first year, 25-30 kW was possible.

I really wish that Nissan would loosen up the allowed regen - it's clear that the battery can take more (cell voltages remain well below 4.1V) and the reduction in regen above and below appx 20 mph really makes a difference for me as I live on a 300 ft hill that I descend every day. Unless there is no traffic behind me and I am able keep my speeds down (and thus regen up), I currently lose about half the regen I would otherwise be able to get. For those days when I start off at 100%, I easily lose 10% efficiency on my commute.

I can attest the car's regen decreases significantly when the battery degrades, which can really hit your range.

Also, with increased internal resistance you WILL notice a difference in QC charging. My battery pack, when degraded maybe held 14 kWh+. Arriving at a QC station with 30-40% remaining, it would take 45 minutes to charge to 80% getting back ~10 kWh. Why do I know this? Because allowing a "30 minute window" for QCing was making me late to many events or I would have to stop the charge early to make it on time. Now take my brand new battery. Arriving at the QC station with the same % remaining, but now, a full battery is 21 kWh and I am charging almost 14 kWh back. 20 minutes flat. Every. Time. I have repeated this and easily confirm. So with 3-4 battery bars lost, your QC time will double for less power. Level 2 times changed less than 30 minutes (on the older 3.3 kW chargers), but it was only barely noticeable (i.e. when I had to public charge). The QC you will definitely notice.

 

[ttweed]

Lost my third bar today at 50,711 miles after 43 months in service. Leaf Spy shows:
AHr=47.47, Gids=201(71.5% @ 94.4% SOC), SOH=72%, Hx=51.76%

Notice the GOM optimistically estimates 84 miles range, while our "everyday" range is more like 55 miles now with our usual mix of street and freeway driving. The car will still do everything we need/want it to do, with a little more opportunity charging and going to 100% every night. We're going to drive it 'til it drops to an un-usable level and then consider replacement options (either the battery or the car). I expected to get 100K miles out of it, but I'm not sure this will be possible.

TT

 

[DaveEV]

We're going to drive it 'til it drops to an un-usable level and then consider replacement options (either the battery or the car). I expected to get 100K miles out of it, but I'm not sure this will be possible.

It looks like you'll be right on the edge of dropping down to 9 bars by the time you hit 60k miles.

This is a great example of how the current "all or nothing" capacity warranty could leave many owners with the short end of the stick, especially considering that it appears that many SoCal (and similar climate) LEAFs will be down 3 bars by the time 5 years / 60k miles rolls by.

FWIW, this is one of my discussion points during the LEAF Advisory Board trip to Japan coming up. If anyone else thinks they are likely to be similarly affected, let me know and I'll take a tally.

 

[kolmstead]

It's amazing what a wide range of Ahr values we see at any particular bar loss reading. My car was at 46.50 Ahr, 50.17% hx yesterday, and the tenth capacity bar remains in place. I expected to lose it a month ago, when the battery still had 47ish Ahr. The P3227 update has delayed my 3rd CB loss by at least six months, which is going to push me up against the 5 year limit on the capacity warranty. I'll still be under on mileage; I only add about 8K per year.

-Karl

 

[blimpy]

Ok...I'm getting the gist of it.

But lets look at NUMBERS..using only L2/L1 charging in moderate climates.

KwH used to charge vs KWh Stored

What I'm hearing is that as the battery degrades and the internal resistance rises, the battery is less able to
accept high current charging ( regen or QC)...( makes sense since it is also less able to deliver same).

What I heard ALSO, is that in low current charging ( 3.3 kw L2 or L1) the TIMES remain the similar.

But does that mean you are using a "same" number of Kwh at your charge station but getting say 30 %
less useful capacity eg Reduced Charge Efficiency (which is what I'd expect of any battery)

Or.. are the mysterious gods of electro-chemistry smiling so overall input/output numbers remain
similar ?

I am ignoring QC because it generates so much waste heat, and accelerates battery decay so much that I won't use it.

 

[blimpy]

Moderator: thanks.. reduced regen was something I didn't know about. We live at 1000 ft
town is 2 miles away and 700 ft lower ! Shopping towns are almost sea level.

This kept me from building a lead acid EV.

Leaf will be used when I get it and we will go out to pasture together .

 

[abasile]

...the current "all or nothing" capacity warranty could leave many owners with the short end of the stick, especially considering that it appears that many SoCal (and similar climate) LEAFs will be down 3 bars by the time 5 years / 60k miles rolls by.

FWIW, this is one of my discussion points during the LEAF Advisory Board trip to Japan coming up. If anyone else thinks they are likely to be similarly affected, let me know and I'll take a tally.

While my mountain climate is cooler, my LEAF's battery capacity is definitely lower than it would have been without heat-related degradation, thanks to time spent at a job "down the hill". I'm expecting it won't be long before the second capacity bar disappears. The capacity might be down roughly 25% by the time the warranty's mileage threshold is reached. At 60K miles, and ~4 years, this seems excessive (compared to other EVs). Most miles have been driven conservatively; rather than mashing the accelerator and pulling 80 kW climbing mountain roads, I've generally driven slowly and used turnouts.

While I'm happy about the availability of replacement batteries for a reasonable price, the fact is that the 2011/2012 battery packs have a real defect. (Not sure about the 2013/2014 packs.) We live with the consequences of that defect every time we would prefer to use the LEAF for errands down the mountain and end up using the Prius instead, for trips that were safe in the LEAF with just 10% more battery capacity and better regen. (Not everyone in my family is prepared to go out of their way to charge the car, and wait, before coming home.) At the same time, the ROI just isn't there for us to pay for battery replacement at this time, unless we could upgrade to a higher capacity battery.

Overall, I feel that Nissan has taken a number of very positive steps. However, many of their early adopters have still been left taking a hit. If Nissan could somehow restore about 10% of my battery pack's original capacity at no charge and give me the "lizard" chemistry, that would be totally equitable IMHO. For others in SoCal, the percentage of capacity to restore would be greater than 10%. I'm not really expecting that, but I would like to be able to upgrade my 2011 LEAF to more than 21 kWh of usable capacity assuming that Nissan upgrades the LEAF's range in a year or two.

 

[Armand]

....

FWIW, this is one of my discussion points during the LEAF Advisory Board trip to Japan coming up. If anyone else thinks they are likely to be similarly affected, let me know and I'll take a tally.

@drees, Thanks for the offer. I live in a cooler part of the SF Bay area and am in a similar situation. I am down one capacity bar and expecting the second one to drop shortly. I will probably miss the warranty deadline by a few months - one of the reasons I opted out.

 

[ttweed]

FWIW, this is one of my discussion points during the LEAF Advisory Board trip to Japan coming up. If anyone else thinks they are likely to be similarly affected, let me know and I'll take a tally.

Thank you, David. That would be a great issue to take up, considering that we were told that the battery pack would lose 30% in 8 years, yet they set the capacity warranty at 5 years and less than 70%. Another BS issue to mention would be the denial of any warranty for those who opted out of the class-action lawsuit.

TT

 

[mwalsh]

Another BS issue to mention would be the denial of any warranty for those who opted out of the class-action lawsuit.

+1. Thanks in advance!

 

[GRA]

We're going to drive it 'til it drops to an un-usable level and then consider replacement options (either the battery or the car). I expected to get 100K miles out of it, but I'm not sure this will be possible.

It looks like you'll be right on the edge of dropping down to 9 bars by the time you hit 60k miles.

This is a great example of how the current "all or nothing" capacity warranty could leave many owners with the short end of the stick, especially considering that it appears that many SoCal (and similar climate) LEAFs will be down 3 bars by the time 5 years / 60k miles rolls by.

FWIW, this is one of my discussion points during the LEAF Advisory Board trip to Japan coming up. If anyone else thinks they are likely to be similarly affected, let me know and I'll take a tally.

By all means, strongly emphasize that a warranty at higher % steps is needed, and a longer one too to match the competition (and their own claims from 2010). If these cars are to have any value on the used market, people have to know what capacity is guaranteed and for how long. Once they get to 150 miles of range only having 70% after x years won't be as critical, but it sure is now.

 

[opencar]

We're going to drive it 'til it drops to an un-usable level and then consider replacement options (either the battery or the car). I expected to get 100K miles out of it, but I'm not sure this will be possible.

It looks like you'll be right on the edge of dropping down to 9 bars by the time you hit 60k miles.

This is a great example of how the current "all or nothing" capacity warranty could leave many owners with the short end of the stick, especially considering that it appears that many SoCal (and similar climate) LEAFs will be down 3 bars by the time 5 years / 60k miles rolls by.

FWIW, this is one of my discussion points during the LEAF Advisory Board trip to Japan coming up. If anyone else thinks they are likely to be similarly affected, let me know and I'll take a tally.

drees,
I'm in the same boat; see my sig; currently at 38K mi, 41 mo, 49.2 Ahr
thanks,

 

[DaveEV]

Thanks everyone - so far around 5 of you that will be borderline. I'm sure there's more. Stoaty's climate sheet clearly shows that just about everyone in any major metro California area will be in the same group.

The class-action lawsuit and opting out's affect on warranty is also on the list already.
So is the idea of having some sort of pro-rated capacity warranty.
And so is Kia's 10 year / 100k mi 70% capacity warranty (battery performance just about all LEAF owners expected with the statements people like Mark Perry made early on) compared to Nissan's 5 year / 60k 66% capacity warranty.

If you have any other ideas for discussion, please bring them up in the LEAF Advisory Board, the sequel thread.

What I heard ALSO, is that in low current charging ( 3.3 kw L2 or L1) the TIMES remain the similar.

No, this is incorrect. L1/L2 charge times, along with energy you can pump into the battery, scale linearly with capacity loss if you are charging from empty to 100%. If you drive the same 20 miles every day with the same efficiency, your charge times will remain identical when comparing a new battery with a 70% capacity battery (with an accurate enough meter/clock you could probably measure some small difference, but it won't be significant).

 

[GregS]

Nissan informs me that the battery capacity gauge bars ACTUAL percentages is proprietary information and cannot be shared with owners, as is the percentage of battery capacity held in reserve when battery is drained to "zero" on the gauge.

 

[TimLee]

Nissan informs me that the battery capacity gauge bars ACTUAL percentages is proprietary information and cannot be shared with owners, as is the percentage of battery capacity held in reserve when battery is drained to "zero" on the gauge.

Well they sure did a lot of public sharing of the first item at the August 2013 dinner :shock: :lol: :shock: :lol:
And the later item has been extensively tested and documented by customers.
21 to 21.5 kWh usable out of 24 kWh pack ultimate capacity.
So why keep calling the info proprietary :?: :?: :?: