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Re: Phoenix Range Test Results, September 15, 2012

Posted: Wed Sep 19, 2012 7:31 am
by Stoaty
edatoakrun wrote:And so, it appears you may have misrepresented the range loss of all the LEAFs tested, by exaggerating the percentages of range lose by about that same 5%. And since you apparently did not collect any data that would allow us to try to estimate actual battery capacity of any of the test cars:

So, the only thing I can conclude from the methodology and results of of this range test, its that eleven of the twelve LEAFs (~ten of which were selected for testing because the owners reported unusually high loss of range) have about 84% to 100% (with a large and unknown level of uncertainty) of what Nissan states (in your single source cited) is "estimated" new LEAF range.
Would it have been better to have a Leaf with 281 Gids at full charge? Of course. However, one thing is clear from Tony's data: the percent Gids is lower than the percent of a "New Leaf Range" (84 miles) in every single case. It is reasonable to infer that a Leaf with 100% Gids would have at least 100% of the "New Leaf Range"--and likely more. My guess is that a Leaf with 100% Gids would travel farther than 84 miles, such that the range loss is probably greater than calculated from the data. If a new Leaf can be found and tested on the same course in similar conditions, I predict that this will be the case.

Re: Phoenix Range Test Results, September 15, 2012

Posted: Wed Sep 19, 2012 7:40 am
by thankyouOB
i looked at the data.
the range does not seem all that bad for these cars, considering that they are supposed to be paradigms of troubled Leafs.

what do we conclude from this?

Re: Phoenix Range Test Results, September 15, 2012

Posted: Wed Sep 19, 2012 7:45 am
by WetEV
edatoakrun wrote:
="TonyWilliams"

Those (m/kWh) numbers were ALL OVER THE PLACE. Not only is that data not needed, you can't prove much with bad data.
It is irresponsible for you to refuse to disclose this "bad data".
Please release the m/kWh numbers.

There is no "bad data". Data can show things other than what is expected, can be not useful, can be hard to interpret, but is never "bad".

The information from the car about the battery is non-ideal. This makes battery loss estimation a lot harder than just plugging in a CAN bus monitor or looking at the capacity bars.

Note that while the battery isn't warrantied, the rest of the car is. That would include the instrumentation. Understand?

Nissan might be as puzzled about parts of this as the rest of us are.

Re: Phoenix Range Test Results, September 15, 2012

Posted: Wed Sep 19, 2012 7:59 am
by edatoakrun
Stoaty wrote:
edatoakrun wrote:And so, it appears you may have misrepresented the range loss of all the LEAFs tested, by exaggerating the percentages of range lose by about that same 5%. And since you apparently did not collect any data that would allow us to try to estimate actual battery capacity of any of the test cars:

So, the only thing I can conclude from the methodology and results of of this range test, its that eleven of the twelve LEAFs (~ten of which were selected for testing because the owners reported unusually high loss of range) have about 84% to 100% (with a large and unknown level of uncertainty) of what Nissan states (in your single source cited) is "estimated" new LEAF range.
Would it have been better to have a Leaf with 281 Gids at full charge? Of course. However, one thing is clear from Tony's data: the percent Gids is lower than the percent of a "New Leaf Range" (84 miles) in every single case. It is reasonable to infer that a Leaf with 100% Gids would have at least 100% of the "New Leaf Range"--and likely more. My guess is that a Leaf with 100% Gids would travel farther than 84 miles, such that the range loss is probably greater than calculated from the data. If a new Leaf can be found and tested on the same course in similar conditions, I predict that this will be the case.
And your guess, may be better than mine.

Since all my level freeway speed driving has been on long trips requiring slow L2 charging, I have never had the luxury of the extra time required to test my LEAFs full range at this speed myself.

I have always thought the range estimates I got from Nissan before I took delivery, and those posted by actual road tests, and later assimilated by Tony into the range chart, were close to correct.

And I would correlate both those sources of estimates, with (very roughly) between ~76 and 80 miles, under the Phoenix test conditions.

Even if you scour the country find a "new" LEAF with the magic gid count you seek (how often do you see 281, at Phoenix range test temperatures?) what evidence would you have that there is not a significant variation in available battery capacity between "new" LEAFs, and that that single LEAF was not atypical?

As an example, I would guess, that "Blue 534" from the test probably would have done 84 miles when new.

Re: Phoenix Range Test Results, September 15, 2012

Posted: Wed Sep 19, 2012 8:12 am
by WetEV
Stoaty wrote:Would it have been better to have a Leaf with 281 Gids at full charge?
I don't trust that "Gids" or capacity bars are accurate. Is there a reason to?

Two cars traveled 79 miles in the test. One had "85%" based on Gids and 12 bars capacity, probably also based on Gids, the other had "75%" and 10 bars.

Re: Phoenix Range Test Results, September 15, 2012

Posted: Wed Sep 19, 2012 8:33 am
by Stoaty
WetEV wrote:I don't trust that "Gids" or capacity bars are accurate. Is there a reason to?
I agree, they are not accurate. However, the values are not random. We see good evidence that there is a systematic bias that under reports the available range. Thus it is reasonable to infer that a Leaf with 100% Gids would have at least 100% of the "New Leaf Range". I can't state it any more plainly than that. Testing a Leaf with 281 Gids is the only way to prove this inference correct.

Re: Phoenix Range Test Results, September 15, 2012

Posted: Wed Sep 19, 2012 8:39 am
by TickTock
Looks like three of the cars dropped a few gids between the time Tony's crew took their data and when I came and repeated at 5am. Was only to capture post drive data for three cars since I was one of the last drivers to return. :-(

Re: Phoenix Range Test Results, September 15, 2012

Posted: Wed Sep 19, 2012 8:42 am
by edatoakrun
I want to reiterate why I think anyone undertaking a range capacity test should record and report all of the m/kWh results from their tests.

It is entirely possible that the gid count itself is the (or, at least one of several) sources of inaccurate kWh use data, the very problem that Nissan is now evidently facing.

As posted a couple months ago:
Ever since TickTock fist (sp) suggested the topic of gid variability, the implications of his observations have been setting in.

"TickTock"

1 gid *mostly* equals 80Wh

http://www.mynissanleaf.com/viewtopic.php?f=44&t=9689" onclick="window.open(this.href);return false;
If “gids” do reflect a variable amount of Wh, and they are the values used by the LEAF to calculate kWh use, then the capacity bar displays, dash and nav screen displays of m/kWh, as well as the Carwings calculations based on these same “gid” values, might be expected to be incorrect as well.

I now believe that this quite possibly could be be the case....
http://www.mynissanleaf.com/viewtopic.p ... 4&start=20" onclick="window.open(this.href);return false;

Re: Phoenix Range Test Results, September 15, 2012

Posted: Wed Sep 19, 2012 8:45 am
by turbo2ltr
So the one thing we know for certain is that we don't know anything for certain. lol.

Don't get me wrong, I understand and respect the pursuit of data. The test has shown a trend that BMS's that think they are connected to batteries with lost capacity trigger turtle after driving less miles. But that's about it.

I'm not of the camp that thinks this is an instrumentation error, but so far no one has proven it isn't. Unfortunately no one will without diving deep into the BMS code, of which I don't think anyone has access to.

Bottom line: Batteries are complex. SOC is a complex calculation. Battery charging is complex. Battery chemestries are complex. There are a lot of variables. More than any test could account for. Not to mention there is this blackbox of a BMS that nobody has a clue how it operates internally. Without this information, I'm afraid we are just spinning our wheels.

I hate to be a naysayer, and maybe if I had bought, I'd be singing a different tune. But I respect Tony and his minions that helped out with this test. It was a HUGE undertaking.

Re: Phoenix Range Test Results, September 15, 2012

Posted: Wed Sep 19, 2012 8:47 am
by kolmstead
thankyouOB wrote:i looked at the data.
the range does not seem all that bad for these cars, considering that they are supposed to be paradigms of troubled Leafs.

what do we conclude from this?

That for freeway driving, with A/C on and going no lower than LBW, the 4-bar car has maybe 45 miles of range.

-Karl