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TonyWilliams
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Re: Range test-determine initial/reduced LEAF battery capaci

Fri Jun 22, 2012 12:07 pm

SanDust wrote:
TonyWilliams wrote:I see it different. A real range test is the only thing that tells you how far it will go (hence my posted parameters). It has nothing to do directly with battery capacity, given other variables. That is for the user to find and determine.
No doubt you'd get a lot more range out of a Leaf over the same route as I would. No argument there. But the OP was trying to use his range on a given route as proof that his battery hadn't degraded. That's different. His battery might not have lost capacity but getting the same range on two different attempts doesn't prove that. For example if I did the first attempt and you did the second then if range indicates battery capacity we'd have to conclude the battery capacity was going up. Then when I did a third attempt we'd have to conclude it was going down!

That, I absolutely agree with. That's why there's specific guidelines in my range protocol to eliminate variables like regeneration, etc.

Thanks for clarifying.

edatoakrun
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Re: Range test-determine initial/reduced LEAF battery capaci

Sat Jun 23, 2012 9:22 am

What the two of you have clarified, is that you are both unaware of Carwings use, and do not comprehend the plain language of my OP.
SanDust:: ...the OP was trying to use his range on a given route as proof that his battery hadn't degraded....
No, I was not. And please do not misrepresent my posts, in the future, as you have so often done in the past.

I explicitly stated that the CW energy report, not a range test, is the most accurate method. of assessing kWh use between different battery pack SOC indicators.:
...you can simply use Carwings, for data of total kWh use between whichever initial charge % and charge end point you select. Any inaccuracies in the CW reports, IMO, are probably not nearly as significant to accuracy, as other variables, such as the “100%” charge level, the battery warnings levels, and unknown battery temperature effects, to name just a few...

(and on the recent tests) I was not trying to replicate speed or other factors leading to my earlier m/kWh performance on this trip, just trying to find the kWh capacity between 100% charge and the same end point...
And I reported that in both recent tests, CW indicated 17.5 kWh use in both recent test from 100% charge to just past VLBW, as opposed to 18.7 in my first test, last Summer.

So, in the simplest analysis, I could conclude this about a 6% reduction in battery capacity was evidence of “degradation”.

However, I believe that there are other factors which cause both the “100%" charge level, and the level of the LBW, to occur at different levels of total capacity.

And I would not make any assertion, of what part of this reduction was a permanent loss in battery capacity, as opposed to a reduction in access to my total battery capacity, imposed by my LEAF’s battery management system.
TonyWilliams:

...That's why there's specific guidelines in my range protocol to eliminate variables like regeneration, etc...
Tony, I would suggest you consider that all three of my range tests I reported here would be impossible on a single charge under your “guidelines”.

This is largely due to your underestimation of recovery of ascent energy, as posted in your range chart, at 50%-75%.

I would think you would come to the same conclusion if you took a look at your energy use during the large ascent/descent segments of your recent BC/BC drive, and would suggest you do so, and correct your range chart to reflect this reality.

Of Course, if you look at the CW reports for the same stretches of road on your recent trip, you should have a far more accurate database to consider.

IMO, there is some more useful information, beyond battery capacity, to be gleaned from my logs of these trips, and I will post more details, as time allows.

The most important point I’d like to make, is that if any suspect you have a significant loss of capacity, such as the “15%” or more that the 12th bar loss is reported to show, I think a range and Carwings kWh use test, such as this, would be very useful, as a battery capacity reduction of that order, should show up much more clearly, above the other “noise” of other available battery capacity and range-affecting factors.
Last edited by edatoakrun on Sun Aug 12, 2012 12:20 pm, edited 1 time in total.
no condition is permanent

chasjacks
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Leaf Number: 004163
Location: Laguna Niguel, CA

Re: Use CW report from range test to determine battery capac

Wed Jul 04, 2012 3:08 pm

Does anyone have an opinion as to whether the update performed at my one-year service check did anything to decrease effective battery capacity? The advisor gave me a 2012 manual and said the car should charge in less time due to update, suggesting they lowered the capacity, possibly to extend life. Or did they recalibrate the way the bars read out? My estimate is that I got about 10 miles from the first bar after 100% charge just prior to update, and now about 5 miles. I have 22K miles and 13 months of driving on my 2011 SL.

Charles

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TomT
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Re: Use CW report from range test to determine battery capac

Wed Jul 04, 2012 3:16 pm

Once gain, the dealer has given bad information. What the update DID do was increase the accuracy of the charging time estimate but the actual time did not change. I saw absolutely no change in range before and after the update, and my bar behavior is as it was before the update. BTW, 10 miles on the first bar, assuming level terrain and other than a considerably low speed, would be exceptional and unusual...
chasjacks wrote:Does anyone have an opinion as to whether the update performed at my one-year service check did anything to decrease effective battery capacity? The advisor gave me a 2012 manual and said the car should charge in less time due to update, suggesting they lowered the capacity, possibly to extend life. Or did they recalibrate the way the bars read out? My estimate is that I got about 10 miles from the first bar after 100% charge just prior to update, and now about 5 miles. I have 22K miles and 13 months of driving on my 2011 SL.
Leaf SL 2011 to 2016, Volt Premier 2016 to 2019, and now:
2019 Model 3; LR, RWD, FSD, 19" Sport Wheels, silver/black; built 3/17/19, delivered 3/29/19.

chasjacks
Posts: 6
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Re: Use CW report from range test to determine battery capac

Wed Jul 04, 2012 3:40 pm

due to update, suggesting they lowered the capacity, possibly to extend life.
Actually they didn't suggest capacity lowering, it was my presumption. At any rate, I definitely see less distance from first bar now, and maybe it's just coincidence I noticed and that my range decrease on that bar was gradual. I typically drive the first five miles at 25-30 mph avg each way to get to freeway, then up to another 3 miles at low speed until traffic speeds pick up where freeway is less congested. It might have been more like 8 miles on first bar before.

SanDust
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Re: Use CW report from range test to determine battery capac

Thu Jul 05, 2012 12:02 am

edatoakrun wrote:What the two of you have clarified, is that you are both unaware of Carwings use, and do not comprehend the plain language of my OP.
...
No, I was not. And please do not misrepresent my posts, in the future, as you have so often done in the past.
...
I explicitly stated that the CW energy report, not a range test, is the most accurate method. of assessing kWh use between different battery pack SOC indicators.:
Sorry if I misinterpreted what you were saying. However, if all you're trying to say is that you start with a 100% charge, run the car until you get a VLB warning, and then use CarWings to see how many kWh you used, why not just say that and skip all the extraneous and extensive range discussion? Just say: I run the car until I get the VLB warning. The next day I check CarWings to find the amount of energy used, which is simply "Energy consumed by the traction motor" + "Energy consumed by the vehicle accessories" - "Energy captured by regenerative braking".

Not valid given how imprecise CarWings is but at least it's clear.

mkjayakumar
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Re: Use CW report from range test to determine battery capac

Thu Jul 05, 2012 7:52 am

There is a lot of merit to the method what OP is suggesting. In essence if Carwaings says I spent 19 kWh from 100% to VLB today and in a month it says I used 18kWh for the same two checkpoints, that means I have lost around 1/19 % = 5.2%.

Seems like a clean way to measure capacity loss, except that you should do that with climate control off (to remove variations between two runs) and also same route.
2011 Leaf, 30K miles, returned after 24 month lease.
Currently leasing 2014 Leaf SV.

SanDust
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Re: Use CW report from range test to determine battery capac

Thu Jul 05, 2012 8:15 am

mkjayakumar wrote:There is a lot of merit to the method what OP is suggesting. In essence if Carwaings says I spent 19 kWh from 100% to VLB today and in a month it says I used 18kWh for the same two checkpoints, that means I have lost around 1/19 % = 5.2%.

Seems like a clean way to measure capacity loss, except that you should do that with climate control off (to remove variations between two runs) and also same route.
What possible difference would climate control make? All you're doing is relying on CarWings to tell give you the total energy expenditure from 100% charge to VLB warning. Doesn't matter what the energy was used for. As Herm mentioned, if you can trust CarWings to give you accurate numbers, which admittedly is a bit crazy, you could just run the heater and not even move the car.

edatoakrun
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Re: Use CW report from range test to determine battery capac

Tue Aug 07, 2012 7:38 am

On 7/31 I tried another range/Capacity test on my usual route. I wanted to see if the recent hotter temperatures might have caused a more rapid seasonal decline in capacity, akin to those reported by gid counts, and in more severe climates, bar loss.

Unfortunately, I had a Nav system failure after 55.4 miles, while stopped on my return leg at the second vertical bar on the trip profile on p 1 of this thread.

http://www.mynissanleaf.com/viewtopic.php?f=30&t=9573" onclick="window.open(this.href);return false;

However, as I was tracking each bar loss as I drove, and did receive the LBW (without the voice-over) I did get a fairly accurate Idea of my capacity relative to my most recent previous test on 6/17. I believe any additional capacity loss was negligible.

Miles at loss for the first 8 bars, and was either at or trailing my previous trip slightly, but only (speed and grade adjusted) representing a small fraction of a kWh of use.

I got the LBW twice-the first time that ever happened to me.

The first LBW (to my great aggravation) was just before Hatchet MT Summit, 72.4 miles into the trip.

The LBW went off, 12.5 miles later, as I regened on the downgrade, then came on again in another 6.4 miles, 91.3 miles into the trip.

I considered driving all the way to VLBW, but decided to call it a day 100.5 miles.

Hopefully, I'll get my car back soon, and will be able take it to VLBC, when I can also get the CW kWh use report.
no condition is permanent

edatoakrun
Posts: 5222
Joined: Thu Nov 11, 2010 9:33 am
Delivery Date: 15 May 2011
Leaf Number: 2184
Location: Shasta County, North California

Re: Use CW report from range test to determine battery capac

Wed Aug 22, 2012 7:18 pm

On Saturday I ran another "100%" capacity range test on this same route, with close to 6,000 ft of ascent and descent.

8/18/12 capacity test results:

107.1 miles to VLBW, 108.0 miles in total, by the odometer.

CW reports 105.4 miles (~2.5% under-report) total miles, at 6.2 m/kWh, 17.0 kWh used from 100% to about the same capacity level, slightly past VLBW.

6/17 (Most recent previous) capacity test results:

110.9 miles to VLB, 112.7 in total, by the odometer.

CW: 109.9 (~2.5% under-report) total miles, at 6.3 m/kWh, 17.5 kWh used from 100% to about the same capacity level, slightly past VLBW.

Very similar temperatures, speeds, and driving conditions on these two days. They were separated by only about 1,700 miles, from ~10,016 to ~11,743 miles at the start of the tests, but also by much of the Summer, and several weeks of the highest (by far) ambient temperatures that my LEAF has experienced since delivery.

Compare these two tests 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.

The lower m/kWh on my earlier tests on the "shorter" route, could be entirely accounted for by the route and speed variations.

The apparent loss of ~ 9% of total battery capacity since 9/7/11, plus an undetermined amount of capacity loss over the summer of 2011, prior to my first range test, might indicate I am close to losing a capacity bar...or it might not.

9/10/12 edit-

Below is a screenshot of my CW "Electric Rate Simulation" including this trip on 8/18/12.

Image

Below are the trip profile and map route, both excluding the first and last ~0.3 miles and ~200 ft of descent and ascent on my driveway, that is not mapped by google.

Trips two and three above correspond to the drive to Burney Falls, the second vertical red line (point C on the map image), and the end of the profile and two red lines correspond to the return trip. The extra miles to initiate the VLBW, came from repeating ~ mile 1 to ~ mile 4 on the profile.

Image

Image
Last edited by edatoakrun on Mon Sep 10, 2012 2:12 pm, edited 1 time in total.
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