Capacity Loss on 2011-2012 LEAFs

[TonyWilliams]

It would seem to me the most reliable test with relying on an Nissan displays would be range measurements. Make sure it is over a known route that has as controllable variables as possible.

http://www.mynissanleaf.com/viewtopic.php?p=184814#p184814" onclick="window.open(this.href);return false;

Checklist before the data collecting run:

1. Any changes to car from stock (different tires, bike rack, Texas cattle horns, etc)
2. Tire pressures set, heater and air conditioning off, car at 100% charge, cells allowed time to balance
3. Gross vehicle weight? 3350 pounds plus operator, passengers, spare tire, bags, concrete, etc
4. Route, length, elevation, hills if any, general conditions (dry, concrete/asphalt, etc)
5. Assumed or measured battery temp (from LEAFscan tool)
6. Ambient air temp
7. Gid count at start, if available
8. SOC, if available (from LEAFscan)
9. Starting total voltage (should be 393.5v from GidMeter or LEAFscan tools)

Data to record:

1. Outbound steady speed (confirm with cruise control on)
2. Outbound observed steady speed miles/kWh from Nav adjusted -0.1
3. Inbound steady speed (confirm with cruise control on)
4. Inbound observed steady speed miles/kWh from Nav adjusted -0.1
5. Miles at Low Battery Warning
6. Miles at Very Low Battery
7. Overall miles covered to Turtle
8. Overall miles/kWh from dash economy display
9. Calculated battery useable energy (miles / miles/kWh = battery kWh)
10.Ending pack voltage, SOC, and Gid (350v-ish from GidMeter or LEAFscan tools)

Post all this data on here for our crack team of LEAFers to decode, but plug the car in to recharge first!

Tony

 

[SanDust]

All the Leaf have run more than 23000km and get the problem, my theory is no matter you take the car or not, when it run around 23000km it will get the problem. These information I get from the charging station provider, they work very close with those company which have Leaf.

That would make sense in that battery degradation is dependent on cycles and the more cycles the more likely you'd see a capacity loss. However, many here are well over 23000 km and haven't experienced a capacity bar loss (I'm at about 30,000 with no bar loss).

 

[Volusiano]

The only thing you can do is a complete cycle and recharge, measuring how much energy you put in.. yes this may require 20 hours of charging on 120V and a kill-a-watt meter... or just wait for the software update.

You still have to use the mile/kwh display from the LEAF to make the calculation.

Not true, the L1 charger which has been documented to charge at 78.3% efficient ( http://www.mynissanleaf.com/viewtopic.php?f=31&t=8583 ) will give you all the information you need. If you put in 20kw then the pack received 15.6kw. So for a new pack you should see 21kw into pack which should pull 26.8kW from the wall.

I was thinking about it from the "charge it up then drive it down (to LBW or VLBW or turtle) to see how many miles you can get out of it" angle, which will need to use the mile/kwh efficiency reading from the LEAF display to calculate how much energy it takes out of the battery, to measure the capacity.

But after reviewing what Herm said further, I understand now that he's taking the opposite approach of just charging it up from a low point (turtle or VLBW or LBW) to 80% or 100% and measure how much energy it takes to fill it up, and deduce the capacity from there after factoring energy inefficiency of the charger, without having to drive the battery down at all.

The problem with Herm's approach is the assumption that reduced capacity implies reduced energy input into the battery. I just don't know if that's a good assumption or not. Maybe it is, maybe it's not. What if reduced capacity simply means that it still requires just as much energy input as when brand new, except that it simply can't hold some of that energy and therefore just gone wasted, and whatever energy left over that it can hold is the reduced capacity? If this is the case, then the "charge up and measure energy input" is not a good approach for capacity measurement.

 

[ColumbiaRiverGorge]

So Carwings says that I used 13.2 k/Wh from 100% to just hitting VLBW for a total of 57.9 miles @ 4.4 m K/wh on 09/03/12. How accurate do you think that 13.2 k/Wh is? and how much is VLBW to turtle?

 

[TonyWilliams]

If this is the case, then the "charge up and measure energy input" is not a good approach for capacity measurement.

I would stay away from battery measurements. Nissan can just reply to you (and a court with a team of engineers / scientists) that they measured the battery and "all was well". Just a software glitch.

The only issue the end user (us) is really concerned about is how far can it go. Even the dumbest juror will understand that when the car was new, it goes this far (then show 5 or 10 cars that were tested right out of the dealer's lot), and now these cars only go XX% of that number in the same conditions.

 

[Volusiano]

If this is the case, then the "charge up and measure energy input" is not a good approach for capacity measurement.

I would stay away from battery measurements. Nissan can just reply to you (and a court with a team of engineers / scientists) that they measured the battery and "all was well". Just a software glitch.

The only issue the end user (us) is really concerned about is how far can it go. Even the dumbest juror will understand that when the car was new, it goes this far (then show 5 or 10 cars that were tested right out of the dealer's lot), and now these cars only go XX% of that number in the same conditions.

I fully agree that the simpler approach for real capacity measurement is to measure how far the battery can take you, not how much energy the battery can soak up on a charge.

However, it's obvious that if you have poor driving conditions vs good driving conditions due to weather/AC use, temperature, freeway vs small roads, lead foot vs hyper miling, altitudes, etc, the range will vary. Therefore, using the "drive the battery down" approach, we still need the miles/kwh driving efficiency readout from the Leaf to calculate the capacity. So I just don't see a clean way to calculate capacity without using any kind of measurement done by the LEAF/Nissan at all.

 

[TonyWilliams]

So I just don't see a clean way to calculate capacity without using any kind of measurement done by the LEAF/Nissan at all.

There absolutely is. Without using ANY instruments from the LEAF (I would actually cover the ENTIRE dash for the tests, and make a point that no data was taken from the LEAF). Drive the car on a specific course (as I've outlined in the post up ^^^ there) at a GPS derived speed of 62.13 mph/100kmh (or 60mph) and drive the car from 100% to Turtle. Neither of these require a specific instrument; the car will fill up until it won't accept any more, and the car will slow down when it hits turtle.

Now, drive the "control" cars (new LEAFs off the dealer lot) under these specific guidelines from that post ^^^ up there.

You'll get:

New Car A - 84.5 miles
New Car B - 86.2 miles
New Car C - 85.4 miles

Then drive the suspect car, on EXACTLY the same course in EXACTLY the same conditions... do it 5 times:

Suspect Car
Drive 1 - 72.3 miles
Drive 2 - 71.3 miles
Drive 3 - 69.8 miles
Drive 4 - 70.0 miles
Drive 5 - 71.2 miles

Note: I recommend all testing be done early in the morning when there's no wind, or late in the evening to match the temperatures. Don't DC charge the batteries, since that will heat them up significantly.

Better yet, have retired or off duty police officer(s) and firemen do the driving for all cars. Remember who the REAL audience for all this stuff. Now, with this data, and the specified parameters, have one of our really sharp statisticians turn that into meaningful information that says, "See, the car doesn't go as far" and we don't really care what the gauges say, or what problems there may be with the battery and/or other parts of the car.

Always be mindful of how Nissan will try to discredit your findings. I can see some of the craziest accusations; GPS isn't accurate to determine speed because there was a sun spot that day(s), then you show how you measured the course and used a stop watch as a backup. Use more than one GPS. Video everything. Expect absolute outright lies and distortion from Nissan legal... for instance, crazy stuff like, "well, this car is a 2011, and those new cars are 2012's, and the 2011 just didn't go as far" and be ready to defend that they are the same car (even late 2011's had optional cold weather package).

Obviously, there are professionals who can do this testing, should a class action become a reality. But, this should get you to first base.

 

[spooka]

I'll take a minute to address your statements/questions, hoping this may clarify some things.

I have no idea what Blink/Ecotality told you.

They state in their questionnaire when you apply for the EV project that they prefer you charge in an enclosed structure.

I think Nissan did not give adequate warning about the effects of high heat, but, IMO, the recommendation to avoid 100% charging whenever possible, to extend battery life, was pretty clear.

This doesn't seem to be a clear cause of the capacity issue many Leafs are seeing. Owners that charge to 80% are reporting the same capacity issue.

So, just how hot is your garage at night, year-round?

Never measured it but very hot without cooling off at all at night during the summer would be an accurate statement. Thanks for giving me the thought to pick up a thermometer to check into this.

How hot is the parking lot, where you park during the day?

During the summer months my estimate would be 100+ for at least 4 hours out of the day (so 12+ hours exposure to 100+ temps weekly).

With so few daily miles driven on average, why did you always recharge to 100%?

I'd get back home with about 7 bars. I never really knew if I would have an extra errand to run the next day and leaving the next day with only 7 bars may have caused an issue, especially with the lack of charging stations in the NW valley in Phoenix where I live. Never a good idea to be stranded in a desert.

Did you re-charge to 100% every night, even when you had a mostly-charged battery?

I never re-charged with an almost full battery.

Most importantly, do you believe that your two capacity bar loss actually represents a loss of more than 21% or more of your original battery capacity?

Yes and here is my reasoning and how I believe it can be ROUGHLY calculated without special instruments.


On September 8, 2011 I made a 40 mile trip and repeated the same trip on 8/31/12. Both days were the same temp and I checked tire pressure before driving. Drove Eco mode the whole way. The only difference is that I have 10 bars on the capacity scale now. The soc bars remaining in both cases after my 40 mile drive had just dropped to the next level and were essentially full bars. Charged to 100% both times.

Leaf dash on 9/8/11
5.8 miles/kwh 41.2 miles driven 6 bars remain 48 miles left on the GOM

Leaf dash on 8/31/12
6.6 miles/kwh 41.3 miles driven 5 bars remain 39 miles left on the GOM



This is my guess on how to obtain a CRUDE estimate of capacity loss based on this info.

I want to use the data provided by the Leaf console to determine the total amount of kwh available to me in the battery pack on each day travelled. I will use this number to determine percentage lost in the battery pack over the last year.


2011 trip

41.2 miles driven divided by 6 bars depleted = 6.86 miles/bar
if I could continue that average for all 12 bars, I could roughly obtain a total of (6.86 miles/bar * 12 bars) 82.4 miles on this charge
82.4 miles divided by the Leaf's reported 5.8 miles/kwh average = 14.28kwh available to use on this charge


2012 trip

41.3 miles driven divided by 7 bars depleted = 5.9 miles/bar
if I could continue that average for all 12 bars, I could roughly obtain a total (5.9 miles/bar * 12 bars) 70.8 miles on this charge
70.8 miles divided by The Leaf's reported 6.6 miles/kwh average = 10.73kwh available to use on this charge

Now to compare the total available charge (capacity) from 2011 and 2012.

10.73kwh divided by 14.28kwh x 100 = 75%


Since I have lost 2 capacity bars up to this point, 75% capacity remaining would fall in line with the table listed below that you quoted.

And is your belief based on an actual range test, on observations of metered or timed recharging, or only on the holy commandments of battery capacity, as carved on tablets here:

Real World Battery Capacity Loss
From MyNissanLeaf...

1 Loss of four battery capacity bars (33.75%)
2 Loss of three battery capacity bars (27.5%)
3 Loss of two battery capacity bars (21.25%)
4 Loss of one battery capacity bar (15%)...

I wish Nissan would provide some answers about all of this and my beliefs about the capacity losses that are being seen mostly in Phoenix are based on posts in this thread (generally) and (personally) through the range test above and the actual range I have now in my Leaf vs a year ago. If my calculations above are correct and the table above is accurate, I should be losing bar #3 soon.

I hope these answers help.

 

[Volusiano]

Then drive the suspect car, on EXACTLY the same course in EXACTLY the same conditions... do it 5 times:

I understand what you're saying here. But this makes it become a very elaborate test. It's appropriate for a law suit or something, and maybe even have independent observers and drivers like you said to ensure the integrity of the test.

But I thought that we're just discussing some basic and simple test for an average Joe owner to do.

 

[nosuchthing]

@RegGuheert

Ca coastal.

Today I upped my tire pressure to 38 so my range should go up to 75-77 (or so I hope). The dealer lowered my pressure a while ago down to 33. They always do that.

 

[edatoakrun]

...On September 8, 2011 I made a 40 mile trip and repeated the same trip on 8/31/12. Both days were the same temp and I checked tire pressure before driving. Drove Eco mode the whole way. The only difference is that I have 10 bars on the capacity scale now. The soc bars remaining in both cases after my 40 mile drive had just dropped to the next level and were essentially full bars. Charged to 100% both times.

Leaf dash on 9/8/11
5.8 miles/kwh 41.2 miles driven 6 bars remain 48 miles left on the GOM

Leaf dash on 8/31/12
6.6 miles/kwh 41.3 miles driven 5 bars remain 39 miles left on the GOM...

Did you make these two drives at about the same speed?

If you had done so, I think that would be evidence that your dash m/kWh report is now under-reporting kWh use, in comparison with ~a year ago, by ~12%.

Please look again at my previous posts. Unexplained increased m/kWh reports from all three sources, dash, nav screen, and CW, on my own range tests from 100% to VLBW (with my speed verified by total drive time) is precisely why I have come to believe there might be a common energy use report error, perhaps the variable Wh content of a "gid", underlying not only the the three m/kWh reports, but the capacity bar display as well.

edatoakrun

The results from 8/30/12 were:

97.3 miles to VLB, 98.9 miles in total, by the odometer.

CW: 96.5 (~2.5% under-report) total miles, at 5.7 m/kWh, 16.8 kWh used from 100% to about the same capacity level, slightly past VLBW.

Compare this test with my first test on 9/7/11:

91.5 miles to VLB, 93.4 in total, by the odometer

CW: 91.1 (~2.5% under-report) total miles, at 4.9 m/kWh, 18.7 kWh used from 100% to about the same capacity level, slightly past VLBW.

http://www.mynissanleaf.com/viewtopic.php?f=30&t=8802&start=3370" onclick="window.open(this.href);return false;

 

[TonyWilliams]

Then drive the suspect car, on EXACTLY the same course in EXACTLY the same conditions... do it 5 times:

I understand what you're saying here. But this makes it become a very elaborate test. It's appropriate for a law suit or something, and maybe even have independent observers and drivers like you said to ensure the integrity of the test.

But I thought that we're just discussing some basic and simple test for an average Joe owner to do.

Average Joe Consumer can do this. Nothing complicated; just follow the steps. Record the data. Two hours out of your life, per vehicle. We spend way more time parsing tidbits with any number of variables, trying to find some factoid. Methodical testing will save time and trouble.

I'm just telling you that you won't get very far with Nissan / Press / Court / Arbitration / Class Action / Lemon Law, etc, with anything less, because they'll just tear it apart. Like WE can tear apart their "data" of "bad instrument", "bad driving techniques", "bad software", etc. Do you want them to refer to you as "hacks using their homemade instrument devices"? You don't need to leave this forum to find plenty of that.

The cars do not go the same distance as new. Methodically, we can "prove" that, to the satisfaction of the press, at least (as a step one). Remember, you get a sound bite in that business, and you better have a strong, singular statement:

The LEAF rapidly loses range autonomy. That's it.

 

[omkar]

Sadly, I've joined the 1 bar lost club today. We've driven the LEAF about 19,000 miles during the 20 months we've owned it. Always have charged to 100%, 10 months exclusively on L1 and then another 10 months exclusively on L2. Car is garaged 90% of the time.

My range hubris decreased after the firmware update at the beginning of the year and has shrunk even more now.

 

[TonyWilliams]

Sadly, I've joined the 1 bar lost club today. We've driven the LEAF about 19,000 miles during the 20 months we've owned it. Always have charged to 100%, 10 months exclusively on L1 and then another 10 months exclusively on L2. Car is garaged 90% of the time.

My range hubris decreased after the firmware update at the beginning of the year and has shrunk even more now.

Sorry to hear a moderate climate like Irvine joining the "11 of 12" ranks. Anything particular about your driving to note? Did you drive to really hot places, like the Inland Empire? Did you leave the car at 100% for long periods of time, particularly in heat?

Tony
Irvine resident, 1986-1988

 

[omkar]

Hmm.. I drive the car pretty hard and it has been in Orange County all the time except for 3 longer trips (2 to LAX and 1 to Pasadena). It is parked in my garage every night and during the day it is in a parking structure but for the last month or two I've been parking on the top level more often (exposed to the sun) as opposed to being covered - work is in Newport Beach/Fashion Island. I don't think I've left the car sitting at 100% for extended periods - whenever we've gone on vacation, I've left the car anywhere between 50-80% charged.

 

[TonyWilliams]

Hmm.. I drive the car pretty hard and it has been in Orange County all the time except for 3 longer trips (2 to LAX and 1 to Pasadena). It is parked in my garage every night and during the day it is in a parking structure but for the last month or two I've been parking on the top level more often (exposed to the sun) as opposed to being covered - work is in Newport Beach/Fashion Island. I don't think I've left the car sitting at 100% for extended periods - whenever we've gone on vacation, I've left the car anywhere between 50-80% charged.

That's what I was afraid of; about as good as one can expect a consumer to treat the car, in an environment that should be a no brainier. My car at 25,300 miles in San Diego beat out a several other cars by not losing a capacity bar (that I know of). While I didn't do anything the Nissan manual says is bad, I certainly used the full performance of the car.

 

[Boomer23]

Sadly, I've joined the 1 bar lost club today. We've driven the LEAF about 19,000 miles during the 20 months we've owned it. Always have charged to 100%, 10 months exclusively on L1 and then another 10 months exclusively on L2. Car is garaged 90% of the time.

My range hubris decreased after the firmware update at the beginning of the year and has shrunk even more now.

Sorry to hear it, Omkar. Your car is about three months older than mine and has about 3,000 fewer miles. Similar climate, but I have always used L2 charging, and usually to 100% for the first 12 months, though I now charge to 80% when possible.

Like most of us, I've been watching my bars closely. So far, my driving range has dropped 13% and possibly a bit more, though I haven't lost a bar.

 

[Herm]

The problem with Herm's approach is the assumption that reduced capacity implies reduced energy input into the battery.

That is a good assumption, a degraded battery will store less energy and require less energy to charge to full.. within limits as there will be increased losses as the pack resistance increases with capacity degradation.

 

[azdre]

It's not standardized, but I did another 100%toLBW test today. 98 degrees, 6 temp bars, 48.0 miles from 100 to LBW @4.5 miles /kWh per middle console in the car. Not cool, Nissan... Not cool.

 

[shrink]

It's not standardized, but I did another 100%toLBW test today. 98 degrees, 6 temp bars, 48.0 miles from 100 to LBW @4.5 miles /kWh per middle console in the car. Not cool, Nissan... Not cool.

I cycle farther than that.

That sucks. Very sorry to hear. Still no word about the Casa Grande 6, huh?

I found this 2-year old article, which has probably been referenced several times previously in this massive thread, and that is sadly appearing prognostic. Be sure to check out the comments (especially those from Charles Whalen) section:

http://www.plugincars.com/tesla-ceo-rips-nissans-battery-technology-says-its-primitive-50527.html" onclick="window.open(this.href);return false;

A few of the quotes that stick out:

Musk believes that because Nissan's battery pack is passively air cooled instead of actively liquid cooled—like Tesla's battery packs—the LEAF's battery temperature will be “all over the place,” and result in “huge degradation.”

Some quotes from Mr. Whalen:

The 15-year on-road experience with Nissan’s lithium-powered EVs in Southern California has seen such high rates of capacity decay and degradation that their lithium battery packs have typically needed to be replaced every couple years. One would hope and presume that this latest iteration of Nissan’s LiMn2O4 batteries that are going into the Leaf is greatly improved over earlier versions

In making the difficult (and painful) decision to match GM’s 8-year battery warranty, Nissan management understood and knew full well that this will result in them taking some losses 4-5 years down the road in having to replace battery packs under warranty in hot climates. For one thing, that’s why they’re encouraging people in hot climates to take the 3-year lease rather than purchasing the car.