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TonyWilliams
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Re: Early Capacity Losses-Was(Lost a bar...down to 11)

Tue Aug 07, 2012 10:49 pm

OrientExpress wrote:This is why a SW bug may very well be the issue.
I don't think we can absolutely rule anything out just yet, but a software issue seems like a long shot, with all the outside data to suggest that this battery chemistry won't do well in severe heat.

The undisputed issue (well, Nissan probably disputes it) is the cars don't go as far as they once did.

opossum
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Leaf Number: 500
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Re: Early Capacity Losses-Was(Lost a bar...down to 11)

Tue Aug 07, 2012 10:52 pm

There is a lawyer out here in the Phoenix area who has been reading up on this capacity loss issue and speaking to some affected LEAF owners. He has experience with the major auto manufacturers as well. He believes LEAF owners have a good claim against Nissan. Message me if you would like the lawyer's contact information.
azdre/opossum, Phoenix, 3/21/11 purchase, 10/2/12 lemon law return.
23k miles, 3 bars lost, officially rated "normal" by Nissan

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TonyWilliams
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Re: Early Capacity Losses-Was(Lost a bar...down to 11)

Tue Aug 07, 2012 10:57 pm

smkettner wrote: I will be curious how your replacement LEAF does on battery capacity. If it degrades the same as the first I would be looking at operating routine. If it lasts much longer I am going to speculate if it is just random luck on how the battery actually performs.
This car has never been to turtle, but at two weeks old, I did 10 DC quick charges in a day with 10 battery temp bars showing when I started charge number eight to 100%.

Would that influence your data control group ? :mrgreen:

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Nubo
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Re: Early Capacity Losses-Was(Lost a bar...down to 11)

Tue Aug 07, 2012 10:58 pm

azdre wrote:
Nubo wrote:
dhanson865 wrote: TickTock compared wall, driving range, gids, bars, carwings, etcetera

wall - this is power in but if power used isn't the full range this doesn't tell us everything - see driving range

driving range - this could be limited by a software bug that shuts down the car before the battery is fully depleted. I'm not saying that is the case but it's the only thing I can see in the list that everything else relates to and OrientExpress is saying we should consider software issues.

gids, bars, carwings - these all go back to whatever software manages the bottom limit on driving range.

I think what Orient Express is saying so caustically is that short of pulling the battery pack out and testing it independent of the leaf's ECUs you are dealing with indirect data and can't be sure it is trustworthy.

But I also have to ask more to be able to defend TickTocks side here. How did you determine driving range? Did you drive until the turle mode stopped working and the leaf was dead and log odometer miles? Or are we talking some less extreme method of measuring drop in driving range?

I'm not in favor of his style of delivery but I think it is worth considering how many computers are inside a single car and how any possible firmware/software/signalling/measuring error could make things complicated.
Agreed. Knowing how much energy the batteries *are* storing does not necessarily tell us how much energy they still *might* be capable of storing, independently of the car's charging and reporting systems.
At the end of the day, the only "measurement" that really matters is that the distance the car can travel has been reduced to the point where the car is no longer useful as a primary commuter, and we are just lucky that we have a Prius and a motorcycle in the garage to augment our travel needs.
Understood but the point trying to be made was that it is still not out of the realm of possibility that a software solution might mitigate some of the loss and restore some ability to store more charge.
I noticed you're still working with polymers.

vegastar
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Re: Early Capacity Losses-Was(Lost a bar...down to 11)

Wed Aug 08, 2012 2:22 am

TickTock wrote:I plotted two charging profile's - one taken last October and the other last month. X axis is the charge from the wall (not charge into the battery) starting from gids=6 to wherever the 100% charge stopped, Y axis is the battery voltage throughout the charge (as reported by canbus). At first glance, it does appear that if the battery voltage sensor is reading about 5V high from last October, that could result in the behavior we are seeing. Shift the red (new) curve down 5V and it looks like it will track the blue (old) curve fairly well and would allow further charging. However, at low charge levels, the curves cross suggesting that the sensor doesn't, at least, have a static offset. It appears it takes the same amount of charge to get to the knee, but the voltage when it reaches there is higher. Maybe someone who understands more about battery chemistry can comment about whether we would expect the voltage of the knee to increase with age.
Amazing data Tick Tock. I have been noticing in my charge logs that the OCV of the LBW and VLBW in my car is much higher than last winter. Example:

March 2012 - 48gids@357.5V
July 2012 - 48gids@360V

For the same voltage I got:

January 2012 - 71gids@362V
July 2012 - 53gids@362V

Until 28-05-2012 (My birthday...) I was ALWAYS seeing 231gids@80% charge. After that it started falling (230 gids at 29-05-2012, my birthday present) and now I am at 215gids@80%charge and stable for 16days (probably because the weather is cooler now). It looks like all of the lost capacity is at the low end of the voltage/charge curve. 71gids@362V - 53gids@362V is 18 gids, 231gids - 18 gids is 213 gids. Hum...
2011 Nissan LEAF since 2011-07-07, 151000 km on 2018-03-03, 7 bars, 37.9Ah.

bioburner
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Re: Early Capacity Losses-Was(Lost a bar...down to 11)

Wed Aug 08, 2012 4:36 am

Bought a Leaf 2011, 4 months ago ,dealer demo with less than 400 miles on it. noticed right away the range was only 50 to 55 miles per charge from 100% charge. The on board computer is telling me we are getting 4.7 to 5.1 miles/KWH (when using the "Energy history" feature). A tipical recharge time is about 3.5 to maybe max of 4 hours. Seems like only half the battery is being used.!!! Now that summer has hit we use the A/C and get only 42 to 45 miles per charge. Seems to me we should be getting 90 to 110 mile per charge even with the A/C running at minimum. All bars are showing on the SOC meter and the car has a total of less than 1600 miles. During the hot weather we recharge at 2 am to be grid friendly and spare the heat in the battery.
The local dealer is tell me there is nothing wrong with the car and a typical recharge cycle is 10 to 12 KWH but they were unable/willing to explain why it only takes 11 KWH to fully recharge a 24 KWH battery.
Does anybody have an explanation as to what is going on?

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RegGuheert
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Re: Early Capacity Losses-Was(Lost a bar...down to 11)

Wed Aug 08, 2012 5:05 am

bioburner wrote:Bought a Leaf 2011, 4 months ago ,dealer demo with less than 400 miles on it. noticed right away the range was only 50 to 55 miles per charge from 100% charge. The on board computer is telling me we are getting 4.7 to 5.1 miles/KWH (when using the "Energy history" feature). A tipical recharge time is about 3.5 to maybe max of 4 hours. Seems like only half the battery is being used.!!! Now that summer has hit we use the A/C and get only 42 to 45 miles per charge. Seems to me we should be getting 90 to 110 mile per charge even with the A/C running at minimum. All bars are showing on the SOC meter and the car has a total of less than 1600 miles. During the hot weather we recharge at 2 am to be grid friendly and spare the heat in the battery.
The local dealer is tell me there is nothing wrong with the car and a typical recharge cycle is 10 to 12 KWH but they were unable/willing to explain why it only takes 11 KWH to fully recharge a 24 KWH battery.
Welcome, bioburner! I'm sorry to hear about your range issues. Can you please give some additional data about your car?
- Have you lost any capacity bars in your LEAF? They are the small bars or ticks just to the right of the charge bars on the dash.
- When was your LEAF manufactured? This information is printed on the lower sticker inside the driver's door on the pillar. I'm going to guess it was around May 2011 based upon your serial number.
- Can you please tell us where you live and place that information in your profile so that we can see it?
- Can you please tell us about your charging and driving habits for the LEAF?
bioburner wrote:Does anybody have an explanation as to what is going on?
I do, assuming you live in a hot climate. The problem is Li-ion batteries degrade quickly if they sit fully charged. That is probably what happened to your LEAF at the dealership before you bought it. In fact, I just started a new thread about that issue: Nissan dealerships torturing LEAF batteries. This thread that you have posted in has all of the technical details regarding what we have learned during the past three months about the effects of heat and high charge levels on LEAF batteries.

Like you, I also purchased a 2011 demo LEAF from a Nissan dealership four months ago. Fortunately for me it was cold most of the time the dealership had the car, so less damage was done, but there still has been some lost range on our LEAF before our purchase.
RegGuheert
2011 Leaf SL Demo vehicle
10K mi. on 041413; 20K mi. (55.7Ah) on 080714; 30K mi. (52.0Ah) on 123015; 40K mi. (49.8Ah) on 020817; 50K mi. (47.2Ah) on 120717; 60K mi. (43.66Ah) on 091918.
Enphase Inverter Measured MTBF: M190, M215, M250, S280

WetEV
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Re: Early Capacity Losses-Was(Lost a bar...down to 11)

Wed Aug 08, 2012 6:31 am

TonyWilliams wrote:
azdre wrote:At the end of the day, the only "measurement" that really matters is that the distance the car can travel has been reduced to the point where the car is no longer useful as a primary commuter
This is where Nissan will lose in the end game.The car was bought and went X miles; less than a year later it goes X - 30% in the exact same conditions.
Two year later, will it be X - 50%? And three year X- 70%? End game loss for Nissan seems very very well assured, if that is the case. Even if Nissan wins in court for every case. Nissan, buy a clue. Or at least rent a hint.

If this was a small fraction of cars everywhere, the "battery abuse is the cause" claim might hold up. For some cars, probably yes. Others, maybe. But not for all.

If this was L2 charged cars only, and L1 charged cars don't have this issue, perhaps a software bug in the charger might be the issue. L1 cars seem to be doing only marginally better.

If this was a bug (or a feature) in the battery management system, then some of the bars and some of the lost range will return with cooler weather. How much? Seems likely to be less than half of the loss is due to this. At most. This isn't completely settled yet (yet Nissan probably knows), only time will tell.

Suggestions to Nissan, as I'm sure they read this:

Make a fair offer to convert sales to leases, and allow for early lease termination on fair terms, on battery capacity loss of 30%(*) or more. Do this soon, before any more lawyers get involved. Do this soon, and make the owners your allies, not your enemies. Nissan has good will from owners. Don't waste it.

Involve owners in the technical detail of this issue, so they expect what happens. Don't let them get shocked by bad results. As it seems likely that temperature is a real issue, improve the data presented to the driver about battery temperatures with a software update. A real battery temperature readout in C (at least), perhaps on the center console. Perhaps a graph of battery temperatures over time, and perhaps even some sort of long term average "estimated loss to to higher than ideal battery temperature". More is better than less. Update the documentation to show what battery capacity loss may be expected under higher temperatures. That way the drivers/owners will know what they are doing to their batteries, and can reduce the damage done. Let me know if I should be putting an AC and insulation in the garage! Let me know if driving on a 40C day will cause capacity loss faster than nominal. Give the drivers/owners the information to reduce capacity loss. It is like putting an oil pressure warning in an ICE. This action will decrease Nissan's future liability. It is in Nissan's interest.

Stop selling Leafs in the hotter areas of the country, at least until the release of more technical detail, and updated instrumentation.

(*) Or even 35% or some other percentage loss. The key idea is to make a fair offer to share risk will remove much (not all) of the anger. Make Nissan and the owners partners and allies, not enemies. Share the risk, don't try to put it all on the owners.
(edited to make what temperature needed displaying, namely battery temperature)
WetEV
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Most everything around here is wet during the rainy season. And the rainy season is long.
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edatoakrun
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Re: Early Capacity Losses-Was(Lost a bar...down to 11)

Wed Aug 08, 2012 7:52 am

"TonyWilliams"

While everybody is pontificating about temperature adjustments to available capacity, please address why I had 15-18% loss of RANGE / AUTONOMY in 75F temperatures?...
How many times did you run your LEAF past VLBW?

To "turtle"?

Until shut-down?
"TonyWilliams"...So, is that the problem with my battery (and not mentioned in the owner's manual)?...
Nissan wrote the manual for the benefit of drivers of an anticipated minimum level of intelligence.

It was undoubtedly assumed, correctly, that drivers would learn their LEAFs battery capacity after a few "turtle" events, and only rarely repeat this experience.

Tony, you are the only LEAF owner anywhere (AFAIK) who, through careful planning, intentionally subjected your battery to charge levels below VLBW dozens (or hundreds? Please report) of times.

Should Nissan now be responsible for not anticipating your behavior, in the owner's manual?

I think it's very unfortunate, that after subjecting your LEAFs battery to these conditions, you sold it, without disclosing your knowledge of its past abuse, and your suspicions of the level of battery degradation, to a new buyer. Now we may never know what the results of your past behavior will be, on this LEAFs future battery capacity.

Continued reports on this LEAFs future battery capacity, would be very valuable information, IMO.
no condition is permanent

SanDust
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Re: Early Capacity Losses-Was(Lost a bar...down to 11)

Wed Aug 08, 2012 8:39 am

TonyWilliams wrote:I don't think we can absolutely rule anything out just yet, but a software issue seems like a long shot, with all the outside data to suggest that this battery chemistry won't do well in severe heat.

The undisputed issue (well, Nissan probably disputes it) is the cars don't go as far as they once did.
If I understand what he's saying, he's saying it is possible that the software is limiting the amount of charge to something below what the battery could potentially take. Since the battery would be holding less charge, all the measurements would be affected and the range would be less, but it could physically take more. It's not a crazy idea. Even if it's not the entire issue it might be part of the issue.

On the other hand, if a cycle is 73 miles, then even a 20% loss at 22K miles would not be a crazy number just based on the cycles (300). You're going to see this effect with any EV that uses a large percentage of its pack. I've assumed (hoped) the cycles would be higher but I haven't seen the specs on this for the AESC batteries.

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