Tool using Nissan's capacity loss benchmarks & 6 scenarios

[Yanquetino]

For anyone interested, I have posted a Capacity Loss Tool. Hope some will find it useful.

 

[richard]

For anyone interested, I have posted a Capacity Loss Tool. Hope some will find it useful and reassuring.

Checking out your tables now. FYI, Scenarios 4 and 5 show Speed as "mpg" instead of "mph". Also, would be clearer if the temperatures specified F or C.

 

[Yanquetino]

Checking out your tables now. FYI, Scenarios 4 and 5 show Speed as "mpg" instead of "mph". Also, would be clearer if the temperatures specified F or C.

Thanks for catching those typos! I've corrected them, and also changed the temperatures to F. I had simply copied-and-pasted them from Nissan's page, but it's true that not specifying the type of degrees could confuse owners overseas. Good suggestion!

 

[surfingslovak]

Mark, commendable effort. I would have couple of comments as well. The 83% charge is actually an 80% charge, which was confirmed by Phil as well. Also, the usefulness of your charts would increase, if you dropped the month/mileage reference, and only retained the battery state of health percentage. I'm pretty sure that the mileage-to-degradation projection does not apply to everyone. My Leaf was down 10% after 15K miles in a temperate California climate last time I looked. A friend asked his dealership to get a readout, and they confirmed 9% after 19K miles in a similar climate.

 

[Yanquetino]

Mark, commendable effort. I would have couple of comments as well. The 83% charge is actually an 80% charge, which was confirmed by Phil as well. Also, the usefulness of your charts would increase, if you dropped the month/mileage reference, and only retained the battery state of health percentage. I'm pretty sure that the mileage-to-degradation projection does not apply to everyone. My Leaf was down 10% after 15K miles in a temperate California climate last time I looked. A friend asked his dealership to get a readout, and they confirmed 9% after 19K miles in a similar climate.

Hi, George:

These are good points, and perhaps I'll make some adjustments. 'Tis true that the Charge Timer control panel gives us the option of 100% or 80% (recommended), but when I do use the 80% option, CarWings always tells me that my pack is now charged to 83%, i.e., 10 of 12 bars. I thus put 83% since that's what (I assume?) other users also see with those notifications, and I didn't want to confuse them. I mean, it is true that 10/12 = 83.34%. Is Phil stating that the setting really does shut off at 80%, but CarWings is "rounding up" the 10th bar to display a slightly exaggerated 83%? If so... sure misleading, and only exacerbates the impression of range loss another 3%!

Hmmm. Well... I think that the months/miles columns are necessary, because the warranty (and thus capacity loss) is based on those two factors --whichever comes first. They are thus what owners would tally by default to get a feel for their "normal" capacity loss.

So, let's say, someone has driven 30,000 miles in only year. That driver should look down the second column (not the first column) to find that mileage, and then consult the estimated range in the two right columns (100% and 83%) --which is roughly ~90%.

If, however, someone has driven only 5,000 miles in 5 years, that person should look down the first column (not the second column) to find 60 months, and then consult the estimated range in the two right columns (100% and 83%) --which is roughly ~80%.

Well... at least that's what one might surmise, given the few parameters Nissan has tossed us.

And no: neither months nor miles will accurately estimate the remaining capacity and range for everyone, precisely because of what Nissan's disclaimer says: the rate of reduction "may be higher or lower," depending upon other factors, including (but not limited to) high heat, charging patterns, driving habits, etc., etc.

Out of curiosity, which scenario(s) best fit for you? Do you think your range is well outside a margin of error for those rough estimates? Are there other factors that you theorize might account for it?

 

[richard]

Mark,

Looking over the tables, I think these could be among the most important resources for would-be buyers to gauge whether the LEAF is for them (and to let current drivers benchmark their own car). I encourage you to get them into PDF format and post them directly to your top post here. At least the EPA driving cycle one. Or, if it can be presented clearly, maybe all the driving cycles can be different columns in a single chart?

Thanks,
Richard

 

[Yanquetino]

Mark,

Looking over the tables, I think these could be among the most important resources for would-be buyers to gauge whether the LEAF is for them (and to let current drivers benchmark their own car). I encourage you to get them into PDF format and post them directly to your top post here. At least the EPA driving cycle one. Or, if it can be presented clearly, maybe all the driving cycles can be different columns in a single chart?

Thanks,
Richard

Thanks, Richard! That's a good suggestion. I might also render the info in a PDF format, once I verify specifics like the 80% vs. 83% issue that George pointed out.

Mark

 

[LEAFfan]

For anyone interested, I have posted a Capacity Loss Tool. Hope some will find it useful and reassuring.

Just wanted to let you know that you have posted info from the old owners' manual (yellow box). QCing more than once a day is NOT harmful to the battery pack. The new manual states that multiple QCs are okay. People need to know the truth so they can freely use this wonderful technology.

 

[Yanquetino]

Just wanted to let you know that you have posted info from the old owners' manual (yellow box). QCing more than once a day is NOT harmful to the battery pack. The new manual states that multiple QCs are okay. People need to know the truth so they can freely use this wonderful technology.

Hi, LEAFfan: Mmm, no: that "yellow box" isn't from an owner's manual --either old or new. It is from the actual disclosure form I had to sign to take delivery of my Leaf last March. I assume that the 2011 disclaimer is the same...? Check your copy and let me know, okay?

And yes: I do remember Mark Perry stating that two or three QCs per day is no longer considered harmful to the pack. I guess that phrase in the disclaimer is simply a holdover from the earliest version of the form. I merely reproduced it, just like it reads, lest anyone think I was "quote mining." Mmmmmaybe I'll just delete that parenthetical sentence to avoid any confusion...?

 

[planet4ever]

'Tis true that the Charge Timer control panel gives us the option of 100% or 80% (recommended), but when I do use the 80% option, CarWings always tells me that my pack is now charged to 83%, i.e., 10 of 12 bars. I thus put 83% since that's what (I assume?) other users also see with those notifications, and I didn't want to confuse them. I mean, it is true that 10/12 = 83.34%. Is Phil stating that the setting really does shut off at 80%, but CarWings is "rounding up" the 10th bar to display a slightly exaggerated 83%? If so... sure misleading, and only exacerbates the impression of range loss another 3%!

Actually, it's both simpler and more complicated than that. CarWings is saying 83% (or 75%) because the only data it gets is "ten bars" (or "nine bars"), so no rounding is involved. This is clearly silly logic, since when you have 0 bars it says you have 0%. In fact you may have up to 15% at that time. But Phil said "80%" is really 80% of current total capacity, not usable capacity. By a curious coincidence that works out to be about 83% of usable capacity.

Ray

 

[surfingslovak]

By a curious coincidence that works out to be about 83% of usable capacity.

Well put, that's absolutely correct. However, there is no such thing as an 83% charge, and I believe that it's potentially confusing to readers. I would nix it for the sake of clarity.

 

[Yanquetino]

'Tis true that the Charge Timer control panel gives us the option of 100% or 80% (recommended), but when I do use the 80% option, CarWings always tells me that my pack is now charged to 83%, i.e., 10 of 12 bars. I thus put 83% since that's what (I assume?) other users also see with those notifications, and I didn't want to confuse them. I mean, it is true that 10/12 = 83.34%. Is Phil stating that the setting really does shut off at 80%, but CarWings is "rounding up" the 10th bar to display a slightly exaggerated 83%? If so... sure misleading, and only exacerbates the impression of range loss another 3%!

Actually, it's both simpler and more complicated than that. CarWings is saying 83% (or 75%) because the only data it gets is "ten bars" (or "nine bars"), so no rounding is involved. This is clearly silly logic, since when you have 0 bars it says you have 0%. In fact you may have up to 15% at that time. But Phil said "80%" is really 80% of current total capacity, not usable capacity. By a curious coincidence that works out to be about 83% of usable capacity.

Ray

Tsk. Yes, it sure sounds simpler yet more complicated! In this case... if the 83% displayed via CarWings really is "83% of usable capacity," wouldn't it be better for me to calculate and list those ranges in my capacity tables? I would imagine that owners would want to know what capacity (range) they could conceivably USE, if need be... wouldn't they?

 

[TonyWilliams]

>>>>Nissan estimates that the capacity might drop to approximately 80% after 5 years (or 62,500 miles) and 70% after 8 years (or 100,000 miles).<<<<<

Since all that data is from Nissan's already generic public data, I see only extrapolating imperfect data, which is less enlightening. It doesn't reflect real life, which does not reflect 70/80% in 5/10 years in Phoenix, for instance in the 100F scenario.

If you had included Nissan's much more recent data of 7500 mile duty cycle years in that 100 degree scenario, and forecasted the more likely scenario of hitting 60,000 miles in 5 years equals at 12,000 miles per year, the actual Nissan data would suggest:

60,000 / 7500 = 8 year degradation data in Phoenix in 5 calendar years. Further, the data has been reindexed, again by Nissan, to 76% in 5 year/7500 mile per year data. The result averages 4.8 % per 5 calendar years using 8 "Nissan-LEAF-Years(TM)" years with 7500 miles per year.

In addition, not indicating a 10% loss the first year is blatantly misleading. You mentioned it, but didn't follow through. Since we must reduce the first year by 10%, subsequent years would then equal 3.4% reduction per NLY. With 8 NLYs in a normal driver's 5 year/12,000 mile driving experience in Phoenix, the final results based on Nissan's data (and not their consumer public data) is:

Year 1 = 90% [100% - 10% first year loss]
Year 2 = 84.56% [90% - (3.4% * (8/5))]
Year 3 = 79.12% [84.56% - (3.4% * (8/5))]
Year 4 = 73.68% [79.12% - (3.4% * (8/5))]
Year 5 = 68.24% [73.68% - (3.4% * (8/5))]
Year10= 41.04% [68.24% - 5(3.4% * (8/5))]

That's just Nissan's formerly secret data applied to the US government statistical 12,000 mile per year driver in Phoenix. This does not impart seasonal losses that must be added to battery capacity in winter (additional 10% loss at 30F, in addition to cabin heater losses (which can be small or quite significant, based on comfort level, preheating, electric seat/steering use, et al).

Winter time available capacity at 30F/0C and one hour of 2kW heating (sorry, running late, can't do proper formula... Estimations):

Year 1 = 80% - 2kWh
Year 2 = 74.56% - 2kWh
Year 3 = 69.12% - 2kWh
Year 4 = 63.68% - 2kWh
Year 5 = 58.24% - 2kWh
Year10= 31.04% - 2kWh

The reality, of course, is that these batteries won't really last 10 years as the energy drops off the cliff in year 3-5, again, the Nissan derived life expectancy (and not consumer generic version).

 

[GRA]

>>>>Nissan estimates that the capacity might drop to approximately 80% after 5 years (or 62,500 miles) and 70% after 8 years (or 100,000 miles).<<<<<

Since all that data is from Nissan's already generic public data, I see only extrapolating imperfect data, which is less enlightening. It doesn't reflect real life, which does not reflect 70/80% in 5/10 years in Phoenix, for instance in the 100F scenario.

If you had included Nissan's much more recent data of 7500 mile duty cycle years in that 100 degree scenario, and forecasted the more likely scenario of hitting 60,000 miles in 5 years equals at 12,000 miles per year, the actual Nissan data would suggest:

60,000 / 7500 = 8 year degradation data in Phoenix in 5 calendar years. Further, the data has been reindexed, again by Nissan, to 76% in 5 year/7500 mile per year data. The result averages 4.8 % per 5 calendar years using 8 "Nissan-LEAF-Years(TM)" years with 7500 miles per year.

In addition, not indicating a 10% loss the first year is blatantly misleading. You mentioned it, but didn't follow through. Since we must reduce the first year by 10%, subsequent years would then equal 3.4% reduction per NLY. With 8 NLYs in a normal driver's 5 year/12,000 mile driving experience in Phoenix, the final results based on Nissan's data (and not their consumer public data) is:

Year 1 = 90% [100% - 10% first year loss]
Year 2 = 84.56% [90% - (3.4% * (8/5))]
Year 3 = 79.12% [84.56% - (3.4% * (8/5))]
Year 4 = 73.68% [79.12% - (3.4% * (8/5))]
Year 5 = 68.24% [73.68% - (3.4% * (8/5))]
Year10= 41.04% [68.24% - 5(3.4% * (8/5))]

That's just Nissan's formerly secret data applied to the US government statistical 12,000 mile per year driver in Phoenix. This does not impart seasonal losses that must be added to battery capacity in winter (additional 10% loss at 30F, in addition to cabin heater losses (which can be small or quite significant, based on comfort level, preheating, electric seat/steering use, et al).

Winter time available capacity at 30F/0C and one hour of 2kW heating (sorry, running late, can't do proper formula... Estimations):

Year 1 = 80% - 2kWh
Year 2 = 74.56% - 2kWh
Year 3 = 69.12% - 2kWh
Year 4 = 63.68% - 2kWh
Year 5 = 58.24% - 2kWh
Year10= 31.04% - 2kWh

Tony, based on Nissan info referenced above which Yanquetino has extrapolated to a linear decrease, I think you should change the degradation modifier on your Range chart to at least 3%/10,000 miles, or 10%/30,000 miles. The former is a slight understatement, the latter a slight overstatement. And add a note to double, triple, quadruple or quintuple it depending on summer temperatures.

 

[surfingslovak]

Tsk. Yes, it sure sounds simpler yet more complicated! In this case... if the 83% displayed via CarWings really is "83% of usable capacity," wouldn't it be better for me to calculate and list those ranges in my capacity tables? I would imagine that owners would want to know what capacity (range) they could conceivably USE, if need be... wouldn't they?

Mark, you are going through the same motions and mistakes several of us went through already. If you cared to have a look, I created a table, which predicts remaining battery capacity and range based on the charging time display. 80% charge clearly shows more than 80% usable capacity. Although the table is dynamic, I did not consider rapid capacity loss when I created it. Likewise, I did not think that LBW and VLBW would be fixed, and not just a percentage of a degraded pack. It's also worth noting that the charging time display exhibits a number of idiosyncrasies, which would be roughly consistent with the performance of other instruments in the car.

http://bitly.com/rangetable

Tony, based on Nissan info referenced above which Yanquetino has extrapolated to a linear decrease, I think you should change the degradation modifier on your Range chart to at least 3%/10,000 miles, or 10%/30,000 miles. The former is a slight understatement, the latter a slight overstatement. And add a note to double, triple, quadruple or quintuple it depending on summer temperatures.

I doubt that these numbers apply to climates other than Phoenix. Mark seemed determined to prove that the situation there was 'normal'. If you applied the same formula to Steve Marsh up in Kent, then he would be down more than 15% based on mileage alone, which would not account for calendar life degradation. I can name a number of vehicles out in the field, where this simple approach won't work. There are few of us that tried to come up with lifecycle predictions, and failed. That's why I would caution anyone to jump to premature conclusions and broadcast them far and wide.

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

 

[TonyWilliams]

Tony, based on Nissan info referenced above which Yanquetino has extrapolated to a linear decrease, I think you should change the degradation modifier on your Range chart to at least 3%/10,000 miles, or 10%/30,000 miles. The former is a slight understatement, the latter a slight overstatement. And add a note to double, triple, quadruple or quintuple it depending on summer temperatures.

Yes, there are a number of changes needed as we learn! I'm not planning any changes anytime soon, but if you have specific formula ideas, throw 'em on the appropriate post.

My 23 year old son used to maintain the website with the range chart, but he passed away this summer, and I don't really have the desire to rebuild it.

 

[Stoaty]

My 23 year old son used to maintain the website with the range chart, but he passed away this summer, and I don't really have the desire to rebuild it.

My condolences. Very sad to hear of your loss.

 

[TonyWilliams]

I doubt that these numbers apply to climates other than Phoenix.

Of course, Phoenix data is what I presented, right out of the Nissan play book.

Mark, you are going through the same motions and mistakes several of us went through already.... Mark seemed determined to prove that the situation there was 'normal'.... That'a why I would caution anyone not to jump to premature conclusions and broadcast them far and wide.

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.

 

[cwerdna]

My 23 year old son used to maintain the website with the range chart, but he passed away this summer, and I don't really have the desire to rebuild it.

My condolences. Very sad to hear of your loss.

+100. Yeah. Sorry to hear about that. That's way too young an age to die.

 

[TonyWilliams]

My 23 year old son used to maintain the website with the range chart, but he passed away this summer, and I don't really have the desire to rebuild it.

My condolences. Very sad to hear of your loss.

+100. Yeah. Sorry to hear about that. That's way too young an age to die.

Guys, thanks, and I don't really want to distract from the thread. I appreciate the thoughts. He had just graduated from college in Phoenix (two weeks prior), had just bought a new house (bank repo) a few months earlier, and also just got a new Prius C. He would have gotten a LEAF, but I feel like we dodged a bullet there.

I was in St. Petersburg, Russia when I learned about it. He is buried just a few miles from where we did our Phoenix range test, so I had a few lumps in my throat while powering through the night there. Thanks again, but again, I don't want to distract from the thread.

My son would have driven 5 Nissan-LEAF-Years(TM) in about 2 earth years!!! He would have been more P.O.'d than me when he had an End Of Life car, and some Nissan dude telling him that was normal !! It really does bother me how this company takes advantage of young people, elderly, and anybody else who can get approved credit to buy/lease this car without the facts that Nissan intentionally withheld.

No surprise, then, that I have a really low tolerance for folks who do Nissan's bidding to continue on as business as usual, keep selling those cars, everything is normal, and as a extra bonus, tell us we're all idiots.