Capacity Loss on 2011-2012 LEAFs

[onlyjaymoo]

I'm in SoCal and I'm glad there's this thread -- been reading through and, though I'm not a GID owner, I know from the average full readings of the guess-o-meter that I have diminished capacity...

Originally I thought it was due to my recent visit for the 15K mi service... maybe they tweaked some software or reset something... but I guess it's just been happening to everyone...

I've got 17K miles, avg 4.2mi/kwh (long time since reset), next month will be my 1 year anniversary of ownership, and I always charge up to 100%.

My typical cycles are like this:

overnight L2 charge to 100%
drive 30 mi to work (used to be 4 bars down, now 5)
garage L1 charge at work to 100%
drive 30 mi home (used to be 4 bars down, now 5)
rinse and repeat

If we go out to dinner (maybe 1-2 times a week), I'll use up an extra 2-3 bars.

I don't feel like I've lost enough yet to see a loss in a bar, but it is definitely noticeable, and I am guessing I'm well on my way.

Oh -- one more thing... I've noticed that the L2 charge times overnight have actually shortened... I always get the sms message sent to me that the charge has completed, and it is definitely taking 15-30min. less time (it always starts at midnight) than it has in the past.

 

[LEAFfan]

For all we know the issue might be as simple as replacing a couple modules and the packs will be on their way. Time will tell

Nope, but I wish! I'm around 10-12% loss right now, and with my yearly battery check, the tech found no bad cells and said (from Nissan) the capacity loss was normal, and that it would level off in the next years (after a one bar loss).

 

[davewill]

... My typical cycles are like this:

overnight L2 charge to 100%
drive 30 mi to work (used to be 4 bars down, now 5)
garage L1 charge at work to 100%
drive 30 mi home (used to be 4 bars down, now 5)
rinse and repeat

If we go out to dinner (maybe 1-2 times a week), I'll use up an extra 2-3 bars. ...

Holy Frijole! If you never run it down more than 4 or 5 bars why in the world aren't you using Long-Life (80%) charging mode? You can always punch the override on the days you're going to take an extra trip. It's one thing to charge to 100% once a day, but twice? For no good reason?

 

[onlyjaymoo]

Holy Frijole! If you never run it down more than 4 or 5 bars why in the world aren't you using Long-Life (80%) charging mode? You can always punch the override on the days you're going to take an extra trip. It's one thing to charge to 100% once a day, but twice? For no good reason?

It's a fair question, but any days that I have to go an "an extra errand" (more than the 1-2 days a week for dinner), is always a 2-3 bar jaunt. These are always 10mi roundtrip errands (because of where I live, everything, including going to the bank, or picking up the kids, or dropping them off at soccer... is like that).

Also, I am not always guaranteed a spot at work where I can charge, which means that if one that I can't charge at work, if I only charged to 80%, all of a sudden, I can't get home (especially now).

... and isn't it always the days you don't know that you need to make an extra trip... that it's critical, didn't plan for it, and can't make it?

 

[Stanton]

It may be a blessing in disguise that I can't charge at work, because if I had the chance, I probably would, AND I probably would have charged to 100% (even though I only do 80% at home), just because it was "free". Knowing what I know now, I doubt I would charge during the day (especially in the summer) even if I had the chance--especially to 100%.

 

[JPWhite]

I'm in the mild San Francisco Bay Area so I'll likely rarely charge or store a battery over 80 degrees F, but I'm going to watch mine closely.

-Phil

You mention 80 degrees. Is this a temp that has been shown to be important to stay under for storage of lithium ion batteries?

Our garage was 78 degrees last night with the door closed. Last summer I left the garage door open to allow the garage to cool. I may resume that practice when temps get up into the 90's in a few weeks.

 

[Ingineer]

You mention 80 degrees. Is this a temp that has been shown to be important to stay under for storage of lithium ion batteries?

Our garage was 78 degrees last night with the door closed. Last summer I left the garage door open to allow the garage to cool. I may resume that practice when temps get up into the 90's in a few weeks.

I mention 80 degrees simply because I doubt I'll ever see it go over that where I live.

Basically all degradation profiles for Lithium-Ion increase with higher temperatures. So generally the cooler the better. (to a point) For instance, storing your battery at high or low SoC for long times is bad, but doing so while hotter is even worse. I don't honestly know what the real quotients are, and they are also likely non-linear, but basically multiply any degradation factor by temperature to get an idea of what I'm talking about.

Nissan immediately voids your warranty if you store them too hot. There's a reason for this!

-Phil

 

[mwalsh]

Just wanted to lt you kids know that I'm home today with 28.4%/80 Gids remaining. This was with about the first 5 miles of the return @ 70mph, the last 8 miles @ 65mph, and the rest in either slow-and-go or stop-and-go traffic. While I maybe would have liked to see ~30% remaining when i pulled into the driveway, the end result is not too far outside of the margin of error.

So I'm tentatively going to say that all is as should be expected from my 17-month old, not particularly babied pack. Still waiting for a super low Gid day before I close the book on my experiences and leave the discussion to you chaps with a more serious issue.

 

[surfingslovak]

You mention 80 degrees. Is this a temp that has been shown to be important to stay under for storage of lithium ion batteries?

Our garage was 78 degrees last night with the door closed. Last summer I left the garage door open to allow the garage to cool. I may resume that practice when temps get up into the 90's in a few weeks.

JP, there is no reason for you to be alarmed. 80F is not a cutoff of any kind, but if you wanted to stay on the conservative side, keeping it closer to 70F will help guarantee long battery life. Please have a look at a post by Charles Whalen. The Volt has a similar battery chemistry, and GM tries to keep it between 70 and 72F whenever possible to minimize degradation.

Additionally, you might want to have a look at this old post, which illustrates how higher temps lead to shorter battery life. Please keep in mind that those graphs were taken from different cells. Although they are not 1:1 transferrable to the Leaf, this might give you an idea how heat can accelerate battery aging.

 

[JPWhite]

You mention 80 degrees. Is this a temp that has been shown to be important to stay under for storage of lithium ion batteries?

Our garage was 78 degrees last night with the door closed. Last summer I left the garage door open to allow the garage to cool. I may resume that practice when temps get up into the 90's in a few weeks.

JP, there is no reason for you to be alarmed. 80F is not a cutoff of any kind, but if you wanted to stay on the conservative side, keeping it closer to 70F will help guarantee long battery life. Please have a look at a post by Charles Whalen. The Volt has a similar battery chemistry, and GM tries to keep it between 70 and 72F whenever possible to minimize degradation.

Additionally, you might want to have a look at this old post, which illustrates how higher temps lead to shorter battery life. Please keep in mind that those graphs were taken from different cells. Although they are not 1:1 transferrable to the Leaf, this might give you an idea how heat can accelerate battery aging.

Thanks for that insight. It's 79 in my garage, 68 outside. Time to open the doors

 

[planet4ever]

Holy Frijole! If you never run it down more than 4 or 5 bars why in the world aren't you using Long-Life (80%) charging mode? You can always punch the override on the days you're going to take an extra trip. It's one thing to charge to 100% once a day, but twice? For no good reason?

It's a fair question, but any days that I have to go an "an extra errand" (more than the 1-2 days a week for dinner), is always a 2-3 bar jaunt.

OK, so you never get below 4 bars. That still makes it a very suboptimal strategy to use.

Also, I am not always guaranteed a spot at work where I can charge, which means that if one that I can't charge at work, if I only charged to 80%, all of a sudden, I can't get home (especially now).

Really? You don't think you can go 60 miles on 80%? You actually can, you know. You just have to slow down coming home on any day you can't get a spot. "Honey, I couldn't charge today, so I'll be 10 minutes late getting home." How big a deal would that be?

... and isn't it always the days you don't know that you need to make an extra trip... that it's critical, didn't plan for it, and can't make it?

Yes, you are right. That can happen, and it might happen on a day when you can't charge at work. Of course if you get home and the little lady says, "We're out of milk and eggs," you can plug the car in and tell her you'll get them after dinner. But there can be emergencies, and maybe you don't have another vehicle. So how about this as a compromise if that's your situation:

• Charge to 100% overnight. Get to work with 7-8 bars.
• Charge to 80% at work. Get home with 4-5 bars.

If you can't charge that day, you get home with 3 bars, and you can still go 20 miles at 60 mph before you get the second battery warning.

Ray

 

[turbo2ltr]

Not sure if anyone already posted this but I just ran my car down to turtle.

Bar 3 went away at 41 GID
Bar 2 at 28
Bar 1 at 10

Compared to 54, 33, and 11 when the car was new.

LBW, VLBW and turtle all occurred at the normal points.

I did notice that I lost NO power bubbles until turtle hit, and at that point it immediately limited to 1 bubble above the center. This is different than what I remember last time I ran down to turtle...which was a long time ago.

I am curious to see what 100% gets me tomorrow.

 

[surfingslovak]

I am curious to see what 100% gets me tomorrow.

+1

Thanks for sharing this! What are the temps like in Phoenix? Was there a sudden change of weather pattern two weeks ago?

 

[TickTock]

Not sure if anyone already posted this but I just ran my car down to turtle.

Bar 3 went away at 41 GID
Bar 2 at 28
Bar 1 at 10

Compared to 54, 33, and 11 when the car was new.

LBW, VLBW and turtle all occurred at the normal points.

I did notice that I lost NO power bubbles until turtle hit, and at that point it immediately limited to 1 bubble above the center. This is different than what I remember last time I ran down to turtle...which was a long time ago.

I am curious to see what 100% gets me tomorrow.

I didn't look for when the bars went away, but I record (among other things) bars and gids at the end of each day. I recently recorded 2 bars with 76 gids remaining and 1 bar with 45 gids remaining. Looks like your threshold for the bars is lower than mine. I *did* get the fw update and I think I recall you mentioning that you didn't. Will have to keep that in mind when you post your 100% level tomorrow.

 

[TickTock]

I just want to say, even if Nissan tested the Leaf in Phoenix, it pretty much had to be an accelerated life test, not the kind of real-time life test currently underway by all of Nissan's Phoenix customers. There are calendar life effects in Lithium chemistries as well as temperature and cycling. They may well interact in non-predictable ways.

I'm in the mild San Francisco Bay Area so I'll likely rarely charge or store a battery over 80 degrees F, but I'm going to watch mine closely.

-Phil

All it would take is one summer to see what we are seeing. I think Arizona *is* the accelerated life test for the rest of the country.

 

[LEAFfan]

Not sure if anyone already posted this but I just ran my car down to turtle.

Bar 3 went away at 41 GID
Bar 2 at 28
Bar 1 at 10
Compared to 54, 33, and 11 when the car was new.
LBW, VLBW and turtle all occurred at the normal points.
I did notice that I lost NO power bubbles until turtle hit, and at that point it immediately limited to 1 bubble above the center. This is different thwhatremember last time I ran down to turtle...which was a long time ago.

I am curious to see what 100% gets me tomorrow.

Interesting, my SoC% has stayed the same for all three...17.4%/8.5%/1.4% even though I've lost 10-12% capacity.

 

[surfingslovak]

LBW, VLBW and turtle all occurred at the normal points.

Interesting, my SoC% has stayed the same for all three...17.4%/8.5%/1.4% even though I've lost 10-12% capacity.

LEAFfan, I believe that Turbo is seeing the same thing. No change for either LBW, VLBW and turtle.

All it would take is one summer to see what we are seeing. I think Arizona *is* the accelerated life test for the rest of the country.

Luke, looking at your spreadsheet, I was going to ask you just that. Did you lose 30 Gids in three months?

 

[Ingineer]

Interesting, my SoC% has stayed the same for all three...17.4%/8.5%/1.4% even though I've lost 10-12% capacity.

LEAFfan, you are not quoting SoC, your scangauge does not access SoC, only the same Gids everyone sees. So this is watt-hours, not SoC. These thresholds are based on watt-hours, not (true) SoC.

-Phil

 

[Volusiano]

Mine is blue (I'm one of the 11 bars'er), and I don't take my Leaf to work, so it doesn't sit outside all day every day for 8 or 9 hours. Most of the times, it sits in the garage during the day in the summer time unless family members take them out to malls or restaurants or errands. But in Phoenix, you tend to shy away from going out during the day in the summer. You wait until evenings when it's cooler before you venture out.

Is your garage inside the air-conditioning envelope for your house? Assuming it is not, does it benefit from the house's air conditioning? What would you estimate is the temperature in your garage on those hottest of days? Your garage peak temperature must be quite a bit below the outdoor peak, right?

Mine is a 4-car garage attached to the house on 1 side (back side) with the garage doors facing north. I have only 2 cars are parked inside, 1 ICE & the Leaf, the other 2 spots are filled with storage stuff. The ICE car was used by my wife for work last summer so it does contribute some heat to the garage when it gets home in the evening, but since last fall until now, it's been much less used since my wife quit that job.

I don't think it benefits from the adjacent air conditioning that much, but at least there's very little evening sun exposure on all 4 sides. I actually have ample attic space above the garage and I cut out 2 1x1 foot square holes on the garage ceiling to allow hot air to escape into the attic out the roof vents. I'd say my garage is probably about 10-15 degrees cooler than the outside during the day.

 

[LEAFfan]

Interesting, my SoC% has stayed the same for all three...17.4%/8.5%/1.4% even though I've lost 10-12% capacity.

LEAFfan, you are not quoting SoC, your scangauge does not access SoC, only the same Gids everyone sees. So this is watt-hours, not SoC. These thresholds are based on watt-hours, not (true) SoC
-Phil

I know that it isn't 'real' SoC, but I don't have the raw numbers that the gauge is
based on so I'm using it for his comparisons. He has different numbers now and mine still read the same.