Yes, but you can't be upset about losing something you weren't expected to have in the first place. It was a bonus that his battery was capable of more ideal miles than most others. They say you'll get 300 ideal miles, so you can't really count anything lost above 300.
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Yes, but you can't be upset about losing something you weren't expected to have in the first place. It was a bonus that his battery was capable of more ideal miles than most others. They say you'll get 300 ideal miles, so you can't really count anything lost above 300.
Peter,
I agree the that the changes in the rated range calculation in the various firmware upgrades would make comparing readings of less than a full charge meaningless. However, if you are comparing the range over time of a full charge, why would using ideal range be any better than using rated range?
The reason I am asking is because the Plug-In America Battery Surveys do just that, compare the rated range of full charges over time.
Thanks.
Larry
I don't know what "full charge" means. That said...
I suspect what bluetinc is saying is that we have strong evidence that "rated" varies from car to car and firmware to firmware. This makes rated numbers not reliable for comparison across cars and over time. In contrast, many believe that "ideal" hasn't been mucked with (other than to rename it in some markets) -- remaining consistent across cars and firmware versions. I'm not sure I believe that, but I think that's what bluetinc is getting at.
JakeP
S P4996 ==> P02547
I'll post this here because it provides an interesting datapoint. My car had a B-pack, and was already running 5.9. I had been pleased to see my rated miles had regained about 6-7 miles at the penultimate hash mark, the highest Daily tick, but below the topmost Trip / Range Mode tick. I originally had 242 miles or better, had gone down to 236 by 5.8, and went back to to 242 miles with 5.9.
My car then experienced the "Painful Clunk", and my pack was replaced with an A-pack. Now I am seeing 222 rated the morning after setting the charge to the same hash mark, though it appears I lost at least a mile or two due to drain. Same car, same firmware, different packs. Of course we don't know any details on the original capacity of my refurb A-pack, but it still makes an interesting data point.
Tesla is replacing this pack with a refurbed B-pack, at my request.
Details on that story can be found here in FlasherZ's thread:
That very loud and painful - Page 11
My car then experienced the "Painful Clunk", and my pack was replaced with an A-pack. Now I am seeing 222 rated the morning after setting the charge to the same hash mark, though it appears I lost at least a mile or two due to drain. Same car, same firmware, different packs. Of course we don't know any details on the original capacity of my refurb A-pack, but it still makes an interesting data point.
Tesla is replacing this pack with a refurbed B-pack, at my request.
Details on that story can be found here in FlasherZ's thread:
That very loud and painful - Page 11
Well, it doesn't necessarily mean charging to the full physical capacity of the battery. It's likely software limited. And thus the actual max charge performed by the vehicle may vary with firmware changes.
I contend the best way to measure degradation is to fully charge, drive to near 0 rated, and see what the energy used since last charge is. Do it again 6 months later. The change in energy usage will measure the change in available energy to the driver. While not an exact measure of pack degradation it's actually more useful to me as a driver.
I would assume that is a given. None of us can fully charge the individual cells unless you hack the car or something. Using the car's normal Range mode , I would think a full charge to most people would mean the max or range charge the car allows.
As I stated I'm asking my question in the context of the Plug-In America Battery Survey. Here's their relevant survey question:
That is what I mean by full charge, 100% maximum range charge.
I guess I'll wait for Peter to tell us what he meant. However, in your opinion if you are comparing the range values of the same car over time using full 100% charges, do you believe that using the ideal range is more accurate than using rated range values?
Thanks.
Larry
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Please refer to my previous posting for what I meant.
So if we use this procedure do you think it matters whether we use ideal versus rated range?
Thanks.
Larry
Larry,
Previously I had been able to confirm that a "Rated Mile" varied from car to car, but at least on my car between 4.0 and 5.8 stayed constant. With 5.9 I was able to confirm that my "Rated Mile" was changed on my car by about 2%, but it appears that the "Ideal Mile" was left alone (at 265 Wh/mi). Furthermore 5.9 remapped the SOC displayed to users vs. the true battery pack voltage. This makes my "Rated Range" comparisons at full charge (Tesla's 100%, 4.15V per cell, etc.) under 5.9 about 2% incorrect, and up to ~10% incorrect at lower displayed SOC's. Using "Ideal" instead, full charge comparisons are correct, but lower SOC states will still show the remapping discrepancy.
Some of the graphs from my data are over in the Decreasing Mileage thread. Decreasing rated range. - Page 121
If you are looking to compare simply "Ideal" 5.8/5.9 vs SOC:
Peter
When on a long trip that requires this, (while not always going down to 0), the amount of energy used has decreased in lock step with my tracking of a full charge, dropping from just over 80kWh -> ~72kWh now.
Except I've read from other owners that any bonus capacity above what Tesla promises is lost pretty quickly. My P85 has the same number of cells as OP's, yet my ideal full range charge is 301 miles. The same cells in his car were able to store 17 miles more, which could be unstable given that Tesla only advertises 300 miles. The 318 miles is an anomaly, may not even be accurate, and doesn't represent the stated capability. For all we know, anything above 300 miles might very well be pretty unstable.
I think that if you are going to calculate degradation, you should do so with Tesla's 300 mile stated capacity as the baseline. Anything above that amount may not be reliable and may be fleeting. As such, using anything above 300 miles as a baseline may seriously skew the results in the wrong direction. You can't use 318 miles because you don't know if those additional 18 miles of capacity will behave the same as the remaining 300 miles. Tesla states 300 miles for a reason, and I presume that reason is because that is the actual capacity that is stable and reliable.
When speaking about warranty guarantees, you are perfectly correct to use the stated 300 miles. But, speaking as an engineer, when tracking degradation you are incorrect to suggest that we replace a measured value with a de-rated number.
In my case, I can tell you that those miles did not suddenly disappear one day, they have consistently decreased since my car was new. They also correspond to the amount of energy that my battery holds. Many cars around mine all showed nearly the same mileage when new, and the newer cars I've personally seen over the last year or so all show within a few percent of the same numbers. Perhaps your numbers are an abnormality?
Peter
In my case, I can tell you that those miles did not suddenly disappear one day, they have consistently decreased since my car was new. They also correspond to the amount of energy that my battery holds. Many cars around mine all showed nearly the same mileage when new, and the newer cars I've personally seen over the last year or so all show within a few percent of the same numbers. Perhaps your numbers are an abnormality?
Peter
Wait, you're saying that my fully charged, ideal range of 301 miles is an abnormality because all cars should get more than that? This would be the first time anyone has suggested that. That implies that anyone who gets the range promised by Tesla has a compromised, reduced range battery. I don't accept that premise.
Hi Peter,
Thanks for your explanation.
So if I understand you correctly it is your opinion that the Plug-In America Battery Survey that asks the for rated range of a full 100% charge over time for the same car is off by about 2%?
Thanks.
Larry
Hi Larry,
Not to cop out on this, but I wouldn't say that anyone else's data except mine (when going from 5.8 -> 5.9) is 2% off. I've been looking for anyone else to track their Ideal miles at 100% across the 5.8->5.9 transition, but everyone has been reporting their rated mile increase. I believe that this may be either a universal change to all cars by 2%, or a switch that brings all cars inline to the same "Rated Mile" energy unit, but with only a data set of 1, I can't commit.
Peter
Well, ideal vs rated becomes meaningless since that's how energy is converted to miles. We start talking in terms of energy, just like we used to talk in terms of gallons of gas. I know that a 100% charge, now, gives me 68 kWh to where I have 10 rated miles left (my comfort level). 6 months ago it was 70 kWh. I presume it was even more when I took delivery but I never checked.
Of course, the energy could be hidden in several different places, not just degradation. There could be a greater buffer when we hit zero rated miles, there could be less access to the top end (software limited) or the pack could be out of balance. But the net is that I have 2kWh less energy available to me that I did 6 months ago. This is valuable information to me and is independent of the rated/ideal range algorithm.
John,
It sounds like your current numbers are just a hair below mine.
I have been watching the start point of the buffer below 0, and the zero mile point has not changed since at least software version 4.0 (Pack voltage of ~316V). So none of the loss that we have seen is attributed to "shifting" of energy below 0. In the same vein, the top end has also not changed (Pack Voltage of ~399V).
I agree that this type of data is better than just about anything else we could capture, but every time I've talked to people about it, getting "good" data has been too complex for the general public. I can say that so far, when I hand calculate numbers using good full charge numbers, I can hand calculate energy usage and end rated miles displayed at the end of a trip down to an error of less than 100 Wh. So, in the end I've been using it simply as validation that my simpler methods are valid.
Peter
It sounds like your current numbers are just a hair below mine.
I have been watching the start point of the buffer below 0, and the zero mile point has not changed since at least software version 4.0 (Pack voltage of ~316V). So none of the loss that we have seen is attributed to "shifting" of energy below 0. In the same vein, the top end has also not changed (Pack Voltage of ~399V).
I agree that this type of data is better than just about anything else we could capture, but every time I've talked to people about it, getting "good" data has been too complex for the general public. I can say that so far, when I hand calculate numbers using good full charge numbers, I can hand calculate energy usage and end rated miles displayed at the end of a trip down to an error of less than 100 Wh. So, in the end I've been using it simply as validation that my simpler methods are valid.
Peter
Hi John,
In your suggested approach after a full 100% charger you drive down to 0 Rated miles. Don't think that your measured energy would be different if you drove down to 0 Ideal miles?
Thanks.
Larry
I think you're saying that the number of rated miles should equal the number of ideal miles at precisely 0 miles. Which I agree with, of course. I've never driven to 0 miles so was using 10 rated as an example since I've hit that number a few times.
No, I don't know for sure but I suspect that driving to zero ideal miles would be different than driving to zero Rated miles and therefore your results in energy used will likely differ.
The fact that you haven't actually followed your suggested methodology to drive to zero suggests that in real life this may not be feasible for most of us to do on a repeated and consistent basis every time we charge to 100%. In other words in real life most of us are not going to be able to drive down to exactly zero each and every time and that will introduce inaccuracies in results.
Larry
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