Tesla's 85 kWh rating needs an asterisk (up to 81 kWh, with up to ~77 kWh usable)

[supratachophobia]

I can understand your confusion, but thusfar, wk057 has not stated which pack variation the cells he put under the testing he is discussing came from.

here's what wk057 said in the first post of this thread as to the origin of the cells he did the month long test on,

"I presently have had roughly 20 pairs of cells from Tesla's "85" kWh pack running 24/7 doing various cycle tests in various conditions. (Eventually I'll be posting detailed data from these tests, but I want to give them significant run times.) These cells were from a pack that had less than 1000 miles (or less than 5 charge cycles) on it, and arrived to me charged to roughly 50% (perfect for storage/shipment)."

understandably, you may have confused wk057's discussion of Panasonic cells with an "A" or "B" designation in comment #48 of this thread with Tesla packs "A" and "B."

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okay, so at 60 mph the Model S has roughly 300 miles of range. so, if I'm not misunderstanding you, 10% less weight would mean 0.6 kWh change in energy needed to travel at that speed per hour... or 3 kWh for the total time to use the vehicle's range capacity. I don't know the source of your data, but it is quite consistent with the point I'm making.

what's more, when you consider that the EPA range is not determined by traveling at 60 mph, but rather by a 5 cycle test, where the cycles average 8.8 miles of length and 11 stops, clearly it is extremely plausible, a 10% weight reduction could easily allow for 4 kWh reduction in battery size to the vehicle while maintaining the 265 mile range.

I think he mentions the source in his other threads, but I could be wrong. And no, I was not confused by the Panasonic numbers.

 

[SteveG3]

Where do you see a 10% weight reduction in the 85?

https://www.teslamotors.com/support/model-s-specifications

https://en.wikipedia.org/wiki/Tesla_Model_S


http://www.edmunds.com/tesla/model-s/2015/sedan/st-200725283/features-specs/


http://www.edmunds.com/tesla/model-s/2013/sedan/features-specs/

see comment #124, details including link to source,

but the main point,

August 2014, Elon Musk on Q2 earnings call with analysts,

"the Model S in production today is at least a few hundred pounds less than that in the start of production. And we'll continue to see improvements over time."

I estimated his at least a few hundred pounds as 350 pounds. as to his continuing to see improvements over time, I estimated that would slow down to about half the pace it had been from start through August 2012, so, that would mean 525 pounds. I'd ballpark it as 10+%.

 

[supratachophobia]

having reread wk057's original post, I have now two alternative hypothesis to wk057's hypothesis... the new one, cell degradation.

I base it on this part of the original post,

"I presently have had roughly 20 pairs of cells from Tesla's "85" kWh pack running 24/7 doing various cycle tests in various conditions. (Eventually I'll be posting detailed data from these tests, but I want to give them significant run times.) These cells were from a pack that had less than 1000 miles (or less than 5 charge cycles) on it, and arrived to me charged to roughly 50% (perfect for storage/shipment)."

and

"In 6 hour charge/discharge cycle testing (1/6C charge and discharge) over a one month period the average capacity of the cells came out to 11.36 Wh per cell. The maximum capacity measured was 11.42 Wh/cell."


we can see from those comments,

- wk057 reports the pack as having had 1,000 miles on it
- reports continuous testing doing 2 charge and discharge full cycles a day for a month... the equivalent of 60 full charges and discharges, which in the real world would mean ~15,500 miles (based on 260 miles per cycle)
- this month straight of charging of discharging was done not within the pack with it's management system

if wk057 took data after each cycle, this means the cells had on the average point when data was taken the equivalent of 8,750 miles on them, with an average of 15 straight days of continuous charge and discharge, all without the benefit of a battery management system.

would anyone really find it shocking if a Model S starting with 1,000 miles had it's battery management system turned off, and for thirty days was continuously charged and discharged and ended up with 4% degradation? my 2012 Model S with 12,000 miles has 3-4% degradation, but trust me, I wouldn't let anyone subject it to the conditions of wk057's testing to see how it would handle another 15,500 miles put on by nonstop charging and use without the benefit of the battery management system.

You forget that he also has access to the CAN network in the car. And the numbers be is pulling from there (a live car in the wild), almost match perfectly; like 1%.

 

[SteveG3]

I think he mentions the source in his other threads, but I could be wrong. And no, I was not confused by the Panasonic numbers.

I'm going on this thread. wk057 can state it if that's the case, as you say, you could be wrong.

sidenote... if your are right, that would be one very unluckly Model S owner... an early 2012 or 2013 (given A or B pack), that they babied about 3 years putting only 1,000 miles on it up until it got totaled on the rare occasion of their driving the car about 3 months ago (two months between getting totaled and delivered to wk057, plus a month of testing).

- - - Updated - - -

You forget that he also has access to the CAN network in the car. And the numbers be is pulling from there (a live car in the wild), almost match perfectly; like 1%.

I believe I've read all of wk057's posts in the thread but I don't know what you are referring to.

 

[Benjamin Brooks]

I believe I've read all of wk057's posts in the thread but I don't know what you are referring to.

It's in the first post.

 

[JRP3]

see comment #124, details including link to source,

but the main point,

August 2014, Elon Musk on Q2 earnings call with analysts,

"the Model S in production today is at least a few hundred pounds less than that in the start of production. And we'll continue to see improvements over time."

I estimated his at least a few hundred pounds as 350 pounds. as to his continuing to see improvements over time, I estimated that would slow down to about half the pace it had been from start through August 2012, so, that would mean 525 pounds. I'd ballpark it as 10+%.

I think you've drastically misinterpreted what was actually said. Let's review:

Elon Musk
Well, the puzzle [ph] on weight versus range is not super strong. There is an improvement but it's not a huge improvement.

As I've been saying.

The Model S has gotten steadily lighter over time. It's really like, you know, it's quarter a pound here, half pound there, but the Model S in production today is at least a few hundred pounds less than that in the start of production. And we'll continue to see improvements over time.

So to get to a step change on -- I mean, there are so many pieces in the car, like you have the battery pack, the motor -- the transmission, or the gear box, the tires and wheels, the seats. I think if you've got like a big improvement any one of those items, maybe with the exception of the battery pack, it only changes the weight of the car by like 1%, 2% or something. These are all good things, but there's not like one big block [indiscernible] sitting in the car that [indiscernible] more primitive. It requires whittling away at a whole bunch of things.

So he's clearly saying there are a number of different components that they have been tweaking to make a bit lighter, yet you are trying to ascribe any and all possible weight reduction to the battery pack. That is obviously not the case.

JB Straubel

And the range impact is, you know, weight is one fraction of impact on range, so, even smaller than the direct percentage of weight reduction."

Again, as I've been saying.

So in summary, any weight reduction in the car has minimal impact on range, and, most importantly, any weight reduction is the result of improvements in many of the car's components, not just the battery pack, and no evidence that it's from a reduction in pack capacity. There is also no support for your guess of 350 lbs of weight reduction, it could be as little as 200 lbs, though there are no figures which I can find to even support that.

 

[SteveG3]

I think you've drastically misinterpreted what was actually said. Let's review:



As I've been saying.


[/B]So he's clearly saying there are a number of different components that they have been tweaking to make a bit lighter, yet you are trying to ascribe any and all possible weight reduction to the battery pack. That is obviously not the case.



Again, as I've been saying.

So in summary, any weight reduction in the car has minimal impact on range, and, most importantly, any weight reduction is the result of improvements in many of the car's components, not just the battery pack, and no evidence that it's from a reduction in pack capacity. There is also no support for your guess of 350 lbs of weight reduction, it could be as little as 200 lbs, though there are no figures which I can find to even support that.

where did you get the idea that I was attributing the weight reduction strictly to the battery?

as to the impact of weight reduction, please see post 196.

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It's in the first post.

okay I see he mentions previous discussion in other threads on this. I'll try to find time to look at those other threads and see if it has relevance to either hypothesis I've offered.

 

[JRP3]

where did you get the idea that I was attributing the weight reduction strictly to the battery?

as to the impact of weight reduction, please see post 196.

I saw it, I don't agree with it, and there you're claiming a 10% reduction in weight, which would mean 465 lbs, and again with no evidence at all of that much weight reduction. I think you need to find a credible documentation of actual weight reduction numbers to have any hope of making your point.

 

[SteveG3]

I saw it, I don't agree with it, and there you're claiming a 10% reduction in weight, which would mean 465 lbs, and again with no evidence at all of that much weight reduction. I think you need to find a credible documentation of actual weight reduction numbers to have any hope of making your point.

if what you are saying is true than Elon Musk lied on a conference call to 20+ analysts 18 months ago as Deepak Ahuja and JB Straubel sat there silently listening to him lie, and if this happened, none of those three or anyone else at Tesla who heard this set the record straight after the fact.

you don't agree with post 196, fair enough, but I don't find your saying you don't agree a convincing rebuttal.

 

[KOL2000]

Sigh. I love tesla but I really wish I had an 85 kWh pack

best ive ever been able to get out of it is about 68 kWh. Here's a screen shot from last trip. Had 2 miles remaining on the meter.

 

[wk057]

Sigh. I love tesla but I really wish I had an 85 kWh pack

best ive ever been able to get out of it is about 68 kWh. Here's a screen shot from last trip. Had 2 miles remaining on the meter.

That from a 90% charge? That's really bad if that was a 100% charge. Looks like it mostly works out for a 90% charge though.

And @SteveG3 is still going on about this weight reduction stuff, and since that wasn't going well tried to read too much into my opening post. *sigh* Being the internet and all, I'll chalk it up to a communication failure somewhere.

11.42 Wh/cell was the maximum that I ever tested for the cells. How long they've been testing doesn't matter since that's the maximum for any of the tests. Not sure how that wasn't clear. Also, testing of a single cell definitely does not need the full battery pack's BMS to be useful. That's absurd.

Seriously, if you're going to try to argue against the data I've presented at least have some actual knowledge of the subject matter beforehand.

 

[JRP3]

if what you are saying is true than Elon Musk lied on a conference call to 20+ analysts 18 months ago as Deepak Ahuja and JB Straubel sat there silently listening to him lie, and if this happened, none of those three or anyone else at Tesla who heard this set the record straight after the fact.

Again, you are jumping to conclusions that have not been presented. I never suggested anything of the sort. Musk never put a number to the weight reduction, and never attributed it to cell density improvements. I'm sure there have been some weight reductions, could even be a bit over 200 lbs or so. That's not 10%, and there is no evidence that it's from increases in cell density coupled with a reduction in pack kWh's. It's also possible that there were weight reductions in some components that were subsequently negated by the addition of or changes to other components.
I"m sorry but you've come up with an unlikely premise with no credible supporting evidence, and I don't think there is any to be had.

 

[AWDtsla]

Sigh. I love tesla but I really wish I had an 85 kWh pack

best ive ever been able to get out of it is about 68 kWh. Here's a screen shot from last trip. Had 2 miles remaining on the meter.

View attachment 110279

No you've gotten more than that. Those numbers are all wrong. Trip meter in the cold, totally wrong.

 

[aus]

Yes, class action lawsuit for all 85 owners to get a free pack upgrade to 90 (which is really 85)! That ought to kill the company... :/ agree it's a big deal but I don't want to see the company fail...

I don't want them to fail either, but if Tesla wants to play with the big boys at big boy prices, they have to STOP LYING about their product.
First there was the whole BS horsepower rating and now the battery rating is totally exaggerated too. It's not like they don't know what the true rating is, so why not just call it an 80??
I'd be perfectly happy with an extra charger to compensate me for knowingly lying to me.

I'm not advocating people getting up in arms and marching an army of lawyers on the lawns of Tesla. Honestly, I'm sure they'd find some loophole or other slick way out of such a lawsuit anyway.

What I do want is for Tesla to start advertising honest specifications for their products. Their products sell themselves. They don't need these lies to push them, and they should realize that.

I agree completely. I'm not a total Tesla fanboi, but I'm obviously a fan since I bought one; I do think Tesla's Sh#t DOES STINK and they've been stinking up the place with their horsepower BS and now this true battery capacity BS.
Don't get me wrong, the car hits it's advertised mark in terms of acceleration and range, so why lie about it?? IT's not like they didn't know both numbers were total BS.
.

 

[Grendal]

I don't want them to fail either, but if Tesla wants to play with the big boys at big boy prices, they have to STOP LYING about their product.

The major manufacturers are constantly lying about their products. Ford and Hyundai lied about their mileage. VW lying is well known. GM yes. I can't even think of a company that hasn't been caught lying. Fudging the numbers is just a given. I think it is also well known that the horsepower rating on regular cars are only ballpark. I'd certainly like Tesla to be perfectly noble but they are playing in a game against all of that. I hope that they are just a little better. Hoping for more than that means that they would probably be throwing themselves on a sword. Look at all the negative publicity they got for the very few car fires they had.

 

[Mike K]

Someone, anyone... Tell me who among us purchased this car based on pack rating alone. And I'm not talking about an 85kwh pack relative to a 60kwh pack. I want to here from those who purchased their car specifically because it was 85kwh and not because it got 265 miles of range. That person doesn't exist thus it is absolutely SILLY for anyone to get bent out of shape about this.

Not to mention all the reasonable people that have already pointed out countless similar examples in the automotive industry that we all accept every day as well as reasonable (and realistic) theories as to why the car may have started out as an 85 and then through the design process was whittled down to an 81 while maintaining range targets.

There are legitimate things about this car to get in a huff over. This isn't one of them. I'm embarrassed for this forum.

 

[Andyw2100]

once more,

"as to why Tesla would do this, isn't it understandable when your product is known to the consumer as either a Model S P85, 85, 60, 85D, 70D, etc., and you continued to offer the exact same range and performance, you would not change the name of a consumer product from those to something like,

February 2013- June 2013: The Model S 84.2 or 59.4

July 2013-December 2013: The Model S 83.3 or 58.8

January 2014- May 2014: The Model S 82.6 or 58.3

June 2014- : The Model S 81.8 or 57.8"



we are talking about a consumer product. we are also talking about a company and their products which are subject to intense media scrutiny, much of it indifferent to the facts (see Tesla fire hazard, Elon Musk carnival barker/welfare leech, Model S 4th or 5th car for the wealthy...).

It took me a while to get caught up in this thread, but I wanted to do that before responding. I was sure others would have pointed out the following, and some people did, in bits, but I'm going to lay it all out in one post to just once and for all invalidate this theory of yours that Tesla was either changing the battery chemistry or reducing the number of cells in the 85 packs over time to yield an equivalent rated range as the cars' weight decreased.

--It is well-known, undisputed fact that the 85 packs have 7104 cells in them. This number has not changed at any point.
--It is well-known, undisputed fact that the battery chemistry in Tesla packs did not change until the introduction of the 90 packs.

Tesla simply could not have been incrementally reducing the size of the 85 pack without either changing the number of cells in the pack or changing the battery chemistry--things we know they did not do. Therefore Tesla did not incrementally reduce the size of the 85 pack to maintain a constant range as the weight of the car was reduced.

 

[stopcrazypp]

--It is well-known, undisputed fact that the 85 packs have 7104 cells in them. This number has not changed at any point.
--It is well-known, undisputed fact that the battery chemistry in Tesla packs did not change until the introduction of the 90 packs.
Tesla simply could not have been incrementally reducing the size of the 85 pack without either changing the number of cells in the pack or changing the battery chemistry--things we know they did not do. Therefore Tesla did not incrementally reduce the size of the 85 pack to maintain a constant range as the weight of the car was reduced.

While I also don't think Tesla had incrementally reduced the capacity of the pack as the weight of the car was reduced, what you set up is a false dilemma. It is possible to have different capacity while not having a "new chemistry" (at least one as different as the 90kWh pack).

I'll show with an example:
NCR18650 (2900 mAh), NCR18650A (3100 mAh), NCR18650BD/NCR18650BE (3200mAh), NCR18650B (3400 mAh) all have different capacity, but follow a similar chemical formula as the 85kWh Model S cells.

The 90kWh uses a partial silicon anode like the NCR18650BF (3200mAh) and NCR18650GA (3500 mAh).

 

[sierra]

Lithium ion batteries degrade with aging. Important factors are temperature and SOC. The degradation due to aging is relatively high with a new battery. With age the loss degradation is slowing down and it seems to almost flatten out.

No scandal - simply degradation due to aging.

 

[stopcrazypp]

The cells I received with my estimate (based on mileage) of ~5 cycles on them were at roughly 55% true SoC when the vehicle was totaled. It was less than 2 months from that point to the time they were in my hands. Can't get too much better than that with these cells, since insurance, auctions, and such take time. However, cells I tested from older vehicles and ones that I know had been sitting for many months prior to reaching me showed no additional degradation from their dormant time. Further, I recently tested a couple of cells that I set aside over a year ago at various SoC and the cells stored at room temp at 50% SoC for over a year showed absolutely no measurable degradation.

Sorry I missed this comment. Calendar life aging begins the day the cells leave the factory. Knowing how long the cells sat after the vehicle was totaled doesn't say much. Knowing how old the car was would be far more helpful and what I was getting at (ideally how old the battery pack was, as it can be newer or older than the car depending on if it ever got swapped and if the pack sat for a while before being installed in a new car).

What we are trying to determine is the capacity of the battery when the car (or battery) rolls out the factory, so calendar life should start counting from that point.