Tool using Nissan's capacity loss benchmarks & 6 scenarios

[surfingslovak]

Certainly, I agree with your comments concerning Mark's motives. It looks like we got to review the work right after he posted on his site.

I just have to cringe a bit after what we've wrestled with for the past year and a half as a group to read some of this author's stuff. I'm not trying to be mean here, or start yet another grade school fight, but it appears to me that Nissan will be "proved" right, whatever the facts are.

I know Mark means well, but his blog post made rounds in the EV community. Unfortunately, many readers don't know the Leaf well enough or don't understand this particular lithium ion chemistry to see through some of the points he makes. It really concerns me, because we have seen these cars in Phoenix, and know how the owners have been treated.

 

[TonyWilliams]

I know Mark means well, but his blog post made rounds in the EV community and many readers don't know the Leaf well enough or don't understand this particular lithium ion chemistry to see through some of the problems. It really concerns me, because we have seen these cars in Phoenix, and know how the owners have been treated.

Well. I know that his stuff is making the rounds, because I get the calls to comment on it. What can I say? Not much.

I also am getting the expected numerous phone calls from lawyers. I'm starting to think maybe that is the right direction to make practical change (in addition to regulatory changes). Certainly, I'll wait for the expected upcoming video chat, info about the board, etc.

Any lawsuits should be in full swing for next summer's LEAF blood bath.

 

[DaveEV]

My 23 year old son used to maintain the website with the range chart, but he passed away this summer.

Wow, my condolences, Tony, really, really sorry to hear that. I can't imagine what it'd be like to lose a child.

(I can move these posts into a separate thread if anyone feels it appropriate).

 

[TonyWilliams]

My 23 year old son used to maintain the website with the range chart, but he passed away this summer.

Wow, my condolences, Tony, really, really sorry to hear that. I can't imagine what it'd be like to lose a child.

(I can move these posts into a separate thread if anyone feels it appropriate).

I don't know... Off topic posts?

 

[azdre]

Certainly, I agree with your comments concerning Mark's motives. It looks like we got to review the work right after he posted on his site.

I just have to cringe a bit after what we've wrestled with for the past year and a half as a group to read some of this author's stuff. I'm not trying to be mean here, or start yet another grade school fight, but it appears to me that Nissan will be "proved" right, whatever the facts are.

I know Mark means well, but his blog post made rounds in the EV community. Unfortunately, many readers don't know the Leaf well enough or don't understand this particular lithium ion chemistry to see through some of the points he makes. It really concerns me, because we have seen these cars in Phoenix, and know how the owners have been treated.

I find it very unfortunate that this person, who has been told that they are publishing inaccurate information, continues to do so without correcting the lies that are posted or the accusations that some of us in Phoenix are lying. It's also seems extremely slimy that such posts would be made in a medium in which no rebuttal is possible.

For what purpose would we have to lie?

I would really love to have the hundres of hours back that I've put into this 'situation', I would really love to continue driving my electric vehicle while experiencing a gradual reduction of driving range. I would love to not have to read drivel and feel the need to constantly defend myself every night. I would love if my spot on the local PBS station, singing the praises of this car and technology were my last time on TV. I may actually cry a little while turning this car back over to Nissan tomorrow.

While you, Mark D Larson, accuse me and others of lying, I know for a fact, that you have lies posted and refuse to correct them and that there were absolutely no lies presented in any news story involving me or my husband. This is the second time that I'm telling you this.

This kerfuffle BS is fraught with libel. Tony, if you are asked for comments, you might want to warn anyone who thinks they can use this as a source that they would be re-distributing lies and I will soon have more time on my hands to deal with such things.

By Nissan's own measurement, my car at 16 months, 19,000 miles would have shown up on your line for 45 months, 45,000 miles. Can't you see the damage you are doing to this car that you want to succeed by fostering false expectations in buyers just like Nissan did? Nissan themselves, admits that the average Phoenix driver is 7,500 miles and that the Phoenix population is on a 'glide path' to AVERAGE 76% at 5 years. The cars tested in Casa Grande are tracking to below 76%, but they won't say how far below 76%. If 19,000 miles is a lot of miles to have on a car, then you may as well kill the EV movement right now!

Finally, I CANNOT WAIT, until you lose 25 miles of range in your car in a single summer. Unfortunately, I would bet that those of us having issues will have blazed a trail for you to have some sort of capacity warranty on your car by then and you'll have a big fat helping of crow for dinner when you're getting your brand new battery pack installed.

 

[EdmondLeaf]

My 23 year old son used to maintain the website with the range chart, but he passed away this summer.

My condolences. Really sorry to hear that.

 

[TonyWilliams]

If 19,000 miles is a lot of miles to have on a car, then you may as well kill the EV movement right now!

Yes, truer words could not have been said. I will say that tomorrow, five seconds after you turn in your LEAF, you can get a new one (on a lease) for pretty darn cheap. Don't discount that.

I wouldn't go over 24 months in PHX, and now that you know the game, and assuming the car will still be useful to you with 30-ish% loss of range at 24 months / 24,000 miles, then I'd just get a new for a whole lot cheaper than you got the one you're turning in.

I'll bet you'll feel a lot better.

 

[RegGuheert]

My 23 year old son used to maintain the website with the range chart, but he passed away this summer.

My condolences, Tony. Our oldest is 22 and I cannot imagine losing him. That's very sad.

 

[GRA]

<snip>
Since we're now seeing reports of 1-bar loss in coastal SoCal and the Bay Area, I think 3%/10k miles may be an understatement, but it (and especially 10%/30k miles) accords well with 20% after 5 years/60,000 miles, which presumably is fairly typical (even if Nissan is figuring 7,500 miles for Phoenix). Even if the rate isn't linear, the cumulative loss over the longer term seems about right.

Checking the Wiki it seems that the reported coastal So Cal and Bay Area 1-bar losses have occured at 16-30k miles. Using the latter, more favorable number implies 5%/10k miles, while the former implies ~9.67%/10k.

 

[Stoaty]

That said, I revisited the model I put together a while ago, added the 7.500 annual miles provision, and the aging factor based on local climate. The results are not 100% accurate, but they seem to roughly match what we have seen in the field so far. I would not want to hazard a guess about what will happen next year, that's why I was hesitant to return to this topic. Comments and suggestions for improvement are welcome.

http://bit.ly/leafbatterydegradationmodel

Well, for Van Nuys, CA (closest to my location, weather perhaps a bit warmer in the summer than where my car lives most of its life) the Gid percentage at one year is pretty much spot on. Only complaint I have is than Van Nuys isn't one of the choices, (but Van Nyus is)

 

[surfingslovak]

Well, for Van Nuys, CA (closest to my location, weather perhaps a bit warmer in the summer than where my car lives most of its life) the Gid percentage at one year is pretty much spot on. Only complaint I have is than Van Nuys isn't one of the choices, (but Van Nyus is)

Very funny, I guess it shows that I've pulled a few late nights at work. Thanks for the feedback, it should be fixed

There seems to be quite a bit of interest in the spreadsheet. You can download a local copy via Files -> Download As -> Microsoft Excel.

 

[Weatherman]

Comments and suggestions for improvement are welcome.

http://bit.ly/leafbatterydegradationmodel

I have a feeling that your aging factor for Ft. Lauderdale may be a bit too low.

I grabbed the hourly temperature data for Ft. Lauderdale Executive Airport (FXE), and I got the following percentage breakdown of time spent at various temperatures over the past five years:

0.07% - above 35C
11.8% - 30C -> 35C
42.9% - 25C -> 35C
31.6% - 20C -> 25C
8.0% - 15C -> 20C
3.7% - 10C -> 15C
Less than 2% of the time below 10C

Since I have the hourly data, I can provide more detail or different temperature break points, if you wish.

 

[GRA]

Comments and suggestions for improvement are welcome.

http://bit.ly/leafbatterydegradationmodel

I have a feeling that your aging factor for Ft. Lauderdale may be a bit too low.

I grabbed the hourly temperature data for Ft. Lauderdale Executive Airport (FXE), and I got the following percentage breakdown of time spent at various temperatures over the past five years:

0.07% - above 35C
11.8% - 30C -> 35C
42.9% - 25C -> 35C
31.6% - 20C -> 25C
8.0% - 15C -> 20C
3.7% - 10C -> 15C
Less than 2% of the time below 10C

Since I have the hourly data, I can provide more detail or different temperature break points, if you wish.

To quote the late, great George Carlin as Al Sleet, the hippy-dippy weatherman:

"It's 88 degrees at the airport, which is stupid, 'cause nobody lives at the airport. Downtown's a lot hotter, man . . . downtown's on FIRE!"

 

[surfingslovak]

I have a feeling that your aging factor for Ft. Lauderdale may be a bit too low.

I grabbed the hourly temperature data for Ft. Lauderdale Executive Airport (FXE), and I got the following percentage breakdown of time spent at various temperatures over the past five years:

0.07% - above 35C
11.8% - 30C -> 35C
42.9% - 25C -> 35C
31.6% - 20C -> 25C
8.0% - 15C -> 20C
3.7% - 10C -> 15C
Less than 2% of the time below 10C

Since I have the hourly data, I can provide more detail or different temperature break points, if you wish.

That's quite possible! I mentioned to Stoaty that I was not able to count the amount of time spent in different temperature bands very accurately. I would like to, but I didn't have time to do it yet. If you like, have a look at the spreadsheet I used to model effective temps for different cities. Please feel free to download and modify it:

http://bitly.com/citytemprofiles" onclick="window.open(this.href);return false;

Note that the Gid counts were included in the degradation model for illustrative purposes only. Gids tend to be depressed in hot climates, and they don't reflect the actual state of battery health accurately. I glanced over Stoaty's excellent analysis on the Wiki, and I believe he made some interesting observations in that regard.

 

[Weatherman]

To quote the late, great George Carlin as Al Sleet, the hippy-dippy weatherman:

"It's 88 degrees at the airport, which is stupid, 'cause nobody lives at the airport. Downtown's a lot hotter, man . . . downtown's on FIRE!"

:lol:

Actually, FXE provides a pretty representative view of what most residents along the southeast Florida coast experience. Downtown Ft. Lauderdale and Ft Lauderdale/Hollywood Airport (FLL) are much closer to the coast, so they tend to be cooler during the day and warmer at night than FXE, which is 5 miles inland.

 

[DaveEV]

It would be nice if we could drop in average hourly data from somewhere to use.

My gut says that we probably want a histogram in 5C increments - 10C increments may not fully capture the Arrhenius Equation.

I also wonder if we might want to apply a night-time adjustment factor to account for parking in the garage at night, since temps in your typical garage normally stay quite a bit warmer than outside temps.

 

[Stoaty]

Comments and suggestions for improvement are welcome.

http://bit.ly/leafbatterydegradationmodel

Link added to Wiki in Battery Capacity Loss Section. One addition I would like to see is a place to put in your months of ownership and total miles on your Leaf to see a predicted capacity loss currently. This might also help to tune the model if there are observations that are far from predicted (e.g., a range test).

 

[Yanquetino]

Comments and suggestions for improvement are welcome.

http://bit.ly/leafbatterydegradationmodel

Link added to Wiki in Battery Capacity Loss Section. One addition I would like to see is a place to put in your months of ownership and total miles on your Leaf to see a predicted capacity loss currently. This might also help to tune the model if there are observations that are far from predicted (e.g., a range test).

Leaf'ers: I mentioned this to George, but he probably hasn't seen the DM. Since I started this thread, and it has since deviated into numerous other topics and tools, might I ask that you have the moderators put the recent discussion into a new, dedicated thread, perhaps something like... "Leaf Battery Degradation Model"?

To clarify, I admire the talent and effort going into this model, and hope it proves a useful utility. My tool, however, had a different intent. It was not to accurately predict capacity and range loss: it was merely to extrapolate for owners and consumers what losses Nissan postulates with the few "benchmarks" and six different "scenarios" the company has made public to date --whether or not they prove accurate.

With time and mileage, users might find through real life experience that George's model provides a reliable, dependable measure, mile-for-mile and year-for-year, to compare with Nissan's claims in the scenario tables. I'm sure we'll all be curious to see how that comparison turns out in the long run.

Thanks!

Mark

 

[Stoaty]

Leaf'ers: I mentioned this to George, but he probably hasn't seen the DM. Since I started this thread, and it has since deviated into numerous other topics and tools, might I ask that you have the moderators put the recent discussion into a new, dedicated thread, perhaps something like... "Leaf Battery Degradation Model"?

It is hard for me to see how a different Capacity Loss Tool (George's model) is off-topic for this thread.

 

[spike09]

Comments and suggestions for improvement are welcome.

http://bit.ly/leafbatterydegradationmodel

Link added to Wiki in Battery Capacity Loss Section. One addition I would like to see is a place to put in your months of ownership and total miles on your Leaf to see a predicted capacity loss currently. This might also help to tune the model if there are observations that are far from predicted (e.g., a range test).

Your model is a great start but I wonder if it really is as simple as x days above y degrees equals z amount of range loss? Isn't this more like trying to predict the weather?

Perhaps using only ambient temperature as a marker is not enough since changes in temperature are a factor as well. You might need to take into account daily variations (day vs night temps), short term variations (how many days the temp stays the same) or seasonal variation (winter vs summer months). I myself wonder if altitude or relative humidity come into play!

As for the LEAF internal variables (KWH usage, miles driven, battery SOC and charging data) we know Nissan must have pretty complete data set from CarWings. Any way to export the data we see on CarWings?

I encourage everyone to post their months of ownership, total miles and number of capacity bars info into their signature. And of course their location and VIN in their profile.

All the best of luck tweaking your model!