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TonyWilliams
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Re: Phoenix Range Test Results, September 15, 2012

Fri Sep 21, 2012 10:00 am

RegGuheert wrote:BTW, what was the voltage of your battery at turtle in the recent test?


Before you guys get too excited about the partial information I gave, two of the cars did not hit turtle (that was my command decision as the last cars were arriving, and we'd already damaged 4 during tows). Not all the drivers got the final voltage, because the Gidmeters were set on Gid # or %.

Here's the list:

LEAF --- CapBars- miles-M/kWh-Volts ---GOM
Red429 --- 10 --- 71.8 - 4.3 - ----------74
Blue494 ---- 8 --- 59.3 - 3.7 - ----------56
Blue534 --- 10 --- 75.7* - --- - 315.5----74 (ECO=84) (*Data edit 75.7 for typo)
White530 -- 10 --- 69.7 - 4.0 - ----------73
White272 -- 10 --- 66.1 - 4.4 - ----------68
Red500 ---- 9 ----73.3*- 4.4 - -342.5*---66 (*No turtle; 2 miles >VLB: Added 4 miles)
White626 --12 ----73.5 - 4.3 - -317.5----73 (CapBars were 10, reset 12, now 11)
Blue842 ---12 ----79.6 - 4.1 - --------- 76
Silver679-- 10 ----71.8 - 4.2 - -303.5--- 75 (18.2 miles after LBW)
Blue917--- 10 ----72.5 - 4.1 - -310.5 ---67
Black782-- 12 ----76.6 - 3.9 - -295.0 ---88ECO (Out4.0/In3.8; LBW 6.9, VLB 6.5)
Blue744 ---9 -----72.3*- 4.4 - -352.0*-- 63 (*No Turtle; 1 mile after VLB; added 5 miles)
Last edited by TonyWilliams on Fri Sep 21, 2012 10:05 am, edited 2 times in total.

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RegGuheert
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Re: Phoenix Range Test Results, September 15, 2012

Fri Sep 21, 2012 10:03 am

TonyWilliams wrote:Before you guys get too excited...
Thanks, Tony! We'll try to contain ourselves! :)
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

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TickTock
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Re: Phoenix Range Test Results, September 15, 2012

Fri Sep 21, 2012 10:34 am

Did we fail to capture mpkwh on Blue534?

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DaveEV
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Re: Phoenix Range Test Results, September 15, 2012

Fri Sep 21, 2012 11:24 am

turbo2ltr wrote:How do you know the whole pack doesn't have a much higher internal resistance and just has a higher open circuit voltage?

An increase in internal resistance doesn't change voltage at rest. It will result in a decrease in voltage under load and an increase in voltage when charging.

TonyWilliams wrote:Before you guys get too excited about the partial information I gave, two of the cars did not hit turtle (that was my command decision as the last cars were arriving, and we'd already damaged 4 during tows). Not all the drivers got the final voltage, because the Gidmeters were set on Gid # or %.

The cars who did not hit turtle should have their results removed. If you want to show the data that was obtained, it should be with a huge * that those cars did not go to turtle and their results have been adjusted. Adding some arbitrary distance to their results is misleading at best unless you've performed a study on these low-capacity cars that conclusively shows the distance a car with the same number of bars will travel between VLBW and turtle.

If you were basing your earlier comments of 60 volt difference between cars at turtle by including these cars, then that's completely misleading since voltage of the pack starts dropping rapidly after VLBW is reached.

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RegGuheert
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Re: Phoenix Range Test Results, September 15, 2012

Fri Sep 21, 2012 11:33 am

drees wrote:
turbo2ltr wrote:How do you know the whole pack doesn't have a much higher internal resistance and just has a higher open circuit voltage?
An increase in internal resistance doesn't change voltage at rest. It will result in a decrease in voltage under load and an increase in voltage when charging.
I'm pretty sure you are both saying the same thing. (I was about to write what you wrote, drees, but then I reread what turbo2ltr said and I saw it can be interpreted pretty much the same way.)
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

palmermd
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Location: Hermosa Beach, CA

Re: Phoenix Range Test Results, September 15, 2012

Fri Sep 21, 2012 11:37 am

drees wrote:The cars who did not hit turtle should have their results removed. If you want to show the data that was obtained, it should be with a huge * that those cars did not go to turtle and their results have been adjusted. Adding some arbitrary distance to their results is misleading at best unless you've performed a study on these low-capacity cars that conclusively shows the distance a car with the same number of bars will travel between VLBW and turtle.

If you were basing your earlier comments of 60 volt difference between cars at turtle by including these cars, then that's completely misleading since voltage of the pack starts dropping rapidly after VLBW is reached.


+1 incomplete data should be clearly marked or kept in a separate table. I'm not a big fan of any of this extra data from instrumentation not in the car from the factory. Charge it until it stop by itself, and then drive it until it stops by itself. How far did it go and how did it do compared to the instrumentation we have in the car.

The instrumentation that was brought along for measuring Gid voltage and such is great to see if we can find some pattern leading us to why this is happening, but all we really know right now is that it is happening and Nissan has been in denial up to now. Sounds like they may be changing their position, and I look forward to their response "soon".
Michael

Leaf from 31 March 2011 - Traded 18 April 2018 for Tesla Model 3 Unicorn
Driving electric since 1996


Leaf Bar Loss

mdh
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Re: Phoenix Range Test Results, September 15, 2012

Fri Sep 21, 2012 11:56 am

Tony... school me here... on the surface it seems like the GOM did a fairly good job? What is the take-away from your view.

Thanks

TonyWilliams wrote:
RegGuheert wrote:BTW, what was the voltage of your battery at turtle in the recent test?


Before you guys get too excited about the partial information I gave, two of the cars did not hit turtle (that was my command decision as the last cars were arriving, and we'd already damaged 4 during tows). Not all the drivers got the final voltage, because the Gidmeters were set on Gid # or %.

Here's the list:

LEAF --- CapBars- miles-M/kWh-Volts ---GOM
Red429 --- 10 --- 71.8 - 4.3 - ----------74
Blue494 ---- 8 --- 59.3 - 3.7 - ----------56
Blue534 --- 10 --- 75.7* - --- - 315.5----74 (ECO=84) (*Data edit 75.7 for typo)
White530 -- 10 --- 69.7 - 4.0 - ----------73
White272 -- 10 --- 66.1 - 4.4 - ----------68
Red500 ---- 9 ----73.3*- 4.4 - -342.5*---66 (*No turtle; 2 miles >VLB: Added 4 miles)
White626 --12 ----73.5 - 4.3 - -317.5----73 (CapBars were 10, reset 12, now 11)
Blue842 ---12 ----79.6 - 4.1 - --------- 76
Silver679-- 10 ----71.8 - 4.2 - -303.5--- 75 (18.2 miles after LBW)
Blue917--- 10 ----72.5 - 4.1 - -310.5 ---67
Black782-- 12 ----76.6 - 3.9 - -295.0 ---88ECO (Out4.0/In3.8; LBW 6.9, VLB 6.5)
Blue744 ---9 -----72.3*- 4.4 - -352.0*-- 63 (*No Turtle; 1 mile after VLB; added 5 miles)

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TonyWilliams
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Re: Phoenix Range Test Results, September 15, 2012

Fri Sep 21, 2012 12:04 pm

TickTock wrote:Did we fail to capture mpkwh on Blue534?


It says 4.4, but a note says that it wasn't reset. I left it out as questionable.

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TonyWilliams
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Re: Phoenix Range Test Results, September 15, 2012

Fri Sep 21, 2012 12:06 pm

mdh wrote:Tony... school me here... on the surface it seems like the GOM did a fairly good job? What is the take-away from your view.


Level terrain, constant speed... yes, the GOM handles that well, as we already know. I'm surprised at how well in this controlled demonstration.

But, if we had cars that had been operated up hills, or driving fast, when we took that first GOM reading, it would not be so good.

So, one win for GOM.

klapauzius
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Re: Phoenix Range Test Results, September 15, 2012

Fri Sep 21, 2012 12:11 pm

TonyWilliams wrote:Here's the list:

LEAF --- CapBars- miles-M/kWh-Volts ---GOM
Red429 --- 10 --- 71.8 - 4.3 - ----------74
Blue494 ---- 8 --- 59.3 - 3.7 - ----------56
Blue534 --- 10 --- 75.7* - --- - 315.5----74 (ECO=84) (*Data edit 75.7 for typo)
White530 -- 10 --- 69.7 - 4.0 - ----------73
White272 -- 10 --- 66.1 - 4.4 - ----------68
Red500 ---- 9 ----73.3*- 4.4 - -342.5*---66 (*No turtle; 2 miles >VLB: Added 4 miles)
White626 --12 ----73.5 - 4.3 - -317.5----73 (CapBars were 10, reset 12, now 11)
Blue842 ---12 ----79.6 - 4.1 - --------- 76
Silver679-- 10 ----71.8 - 4.2 - -303.5--- 75 (18.2 miles after LBW)
Blue917--- 10 ----72.5 - 4.1 - -310.5 ---67
Black782-- 12 ----76.6 - 3.9 - -295.0 ---88ECO (Out4.0/In3.8; LBW 6.9, VLB 6.5)
Blue744 ---9 -----72.3*- 4.4 - -352.0*-- 63 (*No Turtle; 1 mile after VLB; added 5 miles)


Notably the 8 bar car also had the lowest M/kWH, any idea why that is? If we extrapolate to e.g. 4.2 M/kWh, which is the mean for the other cars, it would have gone 67.3 miles, which makes it less of an outlier in terms of range as it appears. This would also lower the overall correlation of observed range with e.g. capacity bars or gids.

Given the variation in (reported) efficiency, one should actually consider the quotient of actual range (lets assume that these values are comparable, i.e. every car was indeed driven to turtle) of range measured divided by efficiency.

The you would get the following list
[Car] [Apparent capacity (=range/efficiency)] [normalized capacity = (apparent cp- <apparent cp>)/std(apparent cp)
Red429 16.7 -0.43
Blue494 16.0 -0.94
Blue534 18.0 0.57
White530 17.4 0.12
White272 15.0 -1.70
Red500 16.7 -0.46
White626 17.0 -0.13
Blue842 19.4 1.63
Silver679 17.1 -0.13
Blue917 17.7 0.31
Black782 19.6 1.8
Blue744 16.4 -0.63
-----------------
mean 17.3 std 1.3

So all tested cars (with this small sample size), fall within 2 standard deviations of the sample mean, so technically, no outliers there. If we now had results for supposedly healthy new batteries (e.g (e.g. for at least 12 (ideally 30 or so) brand new leafs) under the same conditions, we could actually tell which of the tested cars had significant degradation. If we assume that 19.6 apparent capacity (Black782) is representative of the mean for a healthy battery, and we have the same variation as in our sample of 11 bad cars then we have


Red429 -2.59
Blue494 -3.18
Blue534 -1.42
White530 -1.95
White272 -4.07
Red500 -2.63
White626 -2.24
Blue842 -0.20
Silver679 -2.24
Blue917 -1.72
Blue744 -2.83

Which shows that 7 out of these 11 are below 2 std, i.e. are significantly degraded with respect to Black782.
Right now it actually appears that white272 is the worst case (despite a mere 2 bar loss).

Still, since we compute a quotient of two very noisy variables, the error on these values is actually going to be quite high. Also, the sample size is really small....What we really need are ~ 30 new cars tested on the same track.

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