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

Tue Aug 07, 2012 10:41 am

SierraQ wrote: An interesting theory but not likely a significant culprit otherwise we'd be seeing capacity issues everywhere. As it is there is strong evidence that this is solely related to heat and not methods of charging, driving, age, etc. Chargers damage batteries by overcharging or injecting current into them too fast. The Leaf does manage this. Whether it is ideally managed, especially in higher temps, who knows. Still, I don't believe there is clear evidence as yet whether L1 is better than L2. If it is the factor would more likely be the charging voltage/amperage/rate and not the manufacturer since these devices are glorified power switches. Some have reported higher GID counts under L1 but it could be coincidence or insignificant. We would need someone in AZ who has always charged at L1 to have a good comparison point. (Do we have someone like that?)
There's phxsmiley who claims that he was losing 1 GID a day on L2 charging, and stopped losing GIDs on L1 charging. He also said his coworker always charged L1 and never lost capacity.

Maybe it's not L1 vs L2, maybe it's two different EVSE that implement the J1772 protocol with some nuance that combined with heat damages the batteries.

The GE WattStation case is a clear example.

I may be naive, but I believe that Nissan did all the extreme testing to the car to be confident enough to start mass prodution. However, these extreme testing have in common EVSEs designed by Nissan, and being a software engineer I have by experience fallen to the pitfalls of interfacing with external devices that implement features slightly different, and trigger bugs in areas where some things were not supposed to happen.

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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 am

Thank you for not using the GoM or CarWings!!! The center navigation screen reads 0.1 mile/kWh high the driver's dash mount display. Just another goofy "why?" like the two clocks that don't synch up.
opossum wrote:
TonyWilliams wrote:In two to three weeks, I expect a lot of smoke and mirrors.
Tony, I continue to hate you just a little bit for your continued pessimism regarding Nissan's potential handling of this issue... I mean realism... I mean pessimism. :lol: Some of us really need a positive response from them! :?
The whole darn EV movement needs it. It will be tough for BMW, and Tesla, to sell EV's to the unwashed masses when all they know is that the batteries fail. The very fundamental budding block is not adequate.

I sure don't have the answer, since I can't see all of Nissan's cards. Even the best estimate for widespread non-oil cars is decades away, so I can see Nissan thinking that they got their billions in Obama Bucks to build a factory that can make LEAFs -or- other cars that they do make money on (believe me, they haven't made a penny on LEAF). Nissan is golden with CARB with the currnt LEAF population in California; heck, they can sell credits. Audi pulled out of this EV game for now, and BMW and Tesla look like the next "real players". My point is that I can see Nissan cutting their losses.

Now, if you want some smoke blown up your six, I'm probably not the one to do it ;-) Honestly, I hope for the best, but selling 300-500 LEAFs a month jeopardizes even the follow on projects, like the Infiniti EV. The chief promoter, Carlos, has announced he is stepping down. Guys, in the big business of car building, they HAVE to make WAY more, but the "easy" sales are gone (to folks like you and me). Infrastructure in trouble (standards war and poor implementation in the USA).

So simply asked, if you are a Nissan board member, what would you vote for?

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

Tue Aug 07, 2012 11:06 am

jfreire wrote: I may be naive, but I believe that Nissan did all the extreme testing to the car to be confident enough to start mass prodution. However, these extreme testing have in common EVSEs designed by Nissan...
Nissan didn't make any design for any EVSE or charger.

The EVSE in the trunk is Panasonic.

The charger in the car is Nichocon (<--- I know that's misspelled)

The Nissan labeled DC quick charger is Sumitomo.

The Nissan labeled home EVSE is AeroVironment.

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

Tue Aug 07, 2012 11:28 am

TonyWilliams wrote:
jfreire wrote: I may be naive, but I believe that Nissan did all the extreme testing to the car to be confident enough to start mass prodution. However, these extreme testing have in common EVSEs designed by Nissan...
Nissan didn't make any design for any EVSE or charger.

The EVSE in the trunk is Panasonic.

The charger in the car is Nichocon (<--- I know that's misspelled)

The Nissan labeled DC quick charger is Sumitomo.

The Nissan labeled home EVSE is AeroVironment.
I stand corrected! :) What I was trying to illustrate is that all the testing was done with the same models of EVSE known to Nissan, and now there are many more models.

I'm insisting on this issue because I know EVSE matters, and I have an example to prove it, mine!

In Portugal our official "recommended by Nissan" HomeCharger is built by Efacec. During the first month I noticed that the charging was limited to 12A, when it should be limited to 16A.

I talked to Nissan, and they were puzzled by my story and they thought I was reading the power meter wrong. When I talked to Efacec they were quick to blame the power meter, the cables, and the overall electric installation for the 4 missing Amps.
It turned out to be be HomeCharger EVSE equipment, and after the replacement my charging topped at 16A, as expected.

In conclusion: EVSE matters, and it's not that straightforward that it's a simple equipment with absolutely no consequence.

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

Tue Aug 07, 2012 11:38 am

the differences in Nissan's testing versus the leaf community real-world testing is a bit alarming. Opossum getting real world results ~10% less Nissan's offical recording pops up red flags everywhere in my head. Specifically, when reproducing the results both ways (via driving and, I am quite sure via GID) outputting the same results really points to a flaw in Nissan's test.

I hate to think they would go through this entire process only to not run the test correctly or even fudge the results. Neither option is rosey at all. Unfortunately there is very little to counter their actions. Their test show 85% - therefore "normal" (i.e. not below 80% in 5 years) - how could you argue against their test? You could produce all the real world data you want and they can easily point to variables tainted it or their method is best because they made the batteries, etc.

I don't see this ending well. In my limited experience handling product problems with other companies, once they have "their" determination of what is wrong/what is not wrong/how it went wrong, etc. It is hard to argue against that again because they either think: you are one of those crazy people who are never satisfied and will always complain, you are seeing a figment problem, or you are trying to extort/lie to them to get free stuff/repairs. Rarely does further complaining despite overwhelming evidence works. I mean, how can their hired/subcontracted specialist be wrong!

This is what I am scared will happen. They will come back and say 85% no problem, situation normal while we have loads of info to back it up its not, which they will just ignore us entirely and think we are weirdo radicals.

Can anyone speculate the inconsitency? Did nissan try and pull carwings data instead of real testing? :lol: It is fairly obvious that they did little on-the-road testing due to the lack of additional miles, which means computer connections, diagonistics, and simulations. The ONLY way I can see the numbers be reconciled is that Nissan included ALL the kWh in the battery (meaning you still have your 3 kWh you can't touch...duh, that is still good capacity, right?) and then, used the usable capacity as a percentage, inflating the number ~10%.

So, say the Oppossum's car has about 73% capacity remaining of the USABLE battery (~21 kWh) = 15.33 kWh remaining capacity. Add 3 kWh to the total for the unusable capacity, and Oppossum's car has a total of 18.33 kWh of total battery (only 15.33 usable). Now take 18.33 kWh and get a percentage of usable battery (21 kWh) = 87%, to me, very close assuming variables that the top end of 21 kWh is not exact nor is the 15.33 kWh was not exact either. I know, its very bad math (so wrong), but it gives numbers equal to what Nissan says versus Oppossum's real life numbers.

In fact, thinking over it, I bet Nissan is going to pull something close to this out of their hat...i.e. "we never said 70% usable capacity, we said 70% capacity" so their fudge of that ~3 kWh in the battery will play back into their favor. Even if they do the math right, that still may save them against more cars (like mine) to figure a "fix". In addition, because we can't access the entire pack, they can easily pull a "our method is the only way to determine because we can access the full pack, blah blah."
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DaveEV
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Re: Early Capacity Losses-Was(Lost a bar...down to 11)

Tue Aug 07, 2012 11:57 am

Some thoughts based on the last couple pages of this thread:

1. No way different EVSEs can cause advanced battery degradation. All the EVSE does is supply AC power to the car's charger.
2. Since typically the dash gauge is used, Tony's calcs should be adjusted slightly using 4.9mi/kWh - instead of 73% capacity there is 75%. (big deal!)
3. To explain the discrepancy between opposum's tested 75% capacity and Nissan's claimed 85% capacity - that leaves 2 possible conclusions: Nissan assumes that a new car has less available than 21 kWh (18.5 kWh - anything more than that is gravy) - or there is something else going on with the BMS which is limiting available capacity to something lower than what is actually available (most likely culprit - hot battery pack, though it's not clear if the BMS is limiting the top or bottom of the SOC - don't have enough voltage data)

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

Tue Aug 07, 2012 11:59 am

opossum/azdre,

Did you guys received a work order listing exactly what was done to your car? That seems to be standard practice whenever work is performed. I know this case is different, but you have a right to know what they did to the car you own.

Maybe you'll get one in 2-3 weeks when findings are published, but I suggest requesting one for your documentation and records.
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edatoakrun
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Re: Early Capacity Losses-Was(Lost a bar...down to 11)

Tue Aug 07, 2012 12:05 pm

TonyWilliams wrote:Thank you for not using the GoM or CarWings!!! The center navigation screen reads 0.1 mile/kWh high the driver's dash mount display...
That incorrect.

On my LEAF I never reset either display from delivery. As my average m/kWh increased over this Summer, the two screens picked up 0.1 kWh, at different times, (edit-need to dig up paper records for details) indicating a constant ratio, rather than 0.1 mile/kWh.

Of course, you would never see this if you reset frequently, since the numbers would change virtually simultaneously.

AFAIK, I may have been correct, a year ago, when I speculated:
..I suspect Carwings was actually wrong from delivery, and understated mileage by the same 2.5 % as I have seen since the update, and that I just never noticed this relatively small discrepancy.

This could also explain the similar (identical?) 2.5% discrepancy between “dash” and “screen” miles/kWh, which have remained the same on my car, both before and after the update.

Meaning the higher screen number (4.4 m/kWh screen, 4.3 m/kWh dash, on my car since delivery) rather than the dash, may be correct.
http://www.mynissanleaf.com/viewtopic.p ... 3&start=20" onclick="window.open(this.href);return false;
Last edited by edatoakrun on Tue Aug 07, 2012 12:15 pm, edited 1 time in total.
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TickTock
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Re: Early Capacity Losses-Was(Lost a bar...down to 11)

Tue Aug 07, 2012 12:10 pm

Just got my car back too. Was told my capacity was read to be 87% which is also 10% higher then my own repeatable and cross-checked measurements. Only rational explanation I can come up with is they keep seasonal variation separate and are able to distinguish that from permanent degradation. Maybe they cold soaked the battery and ran the test - we'll find out in a few months, I guess.

My capacity bars, also, were reset so I am now showing 12 bars capacity again.

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

Tue Aug 07, 2012 12:15 pm

drees wrote:...
3. To explain the discrepancy between opposum's tested 75% capacity and Nissan's claimed 85% capacity - that leaves 2 possible conclusions: Nissan assumes that a new car has less available than 21 kWh (18.5 kWh - anything more than that is gravy)...
Very good point, Dave!

Please have a look at the chart from NTB11-076a that azdre linked to:
azdre wrote:Our last range test, we averaged 5.0 miles /kWh (per dash) and drove 58.6 miles from 100% to LBW. According to the technical bulletin released a new battery should get 75-85 miles to LB, last summer we were right about 80.

http://www.mynissanleaf.com/viewtopic.p ... &start=357" onclick="window.open(this.href);return false;
If you calculate the numbers from that chart, it becomes clear that Nissan used 18.8 to 19 kWh for the low end of a new LEAF battery and 20.8 to 21 kWh for the high end.

So it seems quite possible that Nissan will officially consider ALL LEAFs to have only 19 kWh of usable capacity when new and will calculate loss based on that, even if that particular LEAF really started out with 21 kWh. I don't agree with that approach, but it does make the calculation as far in their favor as they can manage and could easily explain the current discrepancy at hand.
RegGuheert
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