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

[Pruitt]

It could be as simple one of these:

1. The design goal was 85 kWh. All the marketing folks ran with that. As the detailed design work was done, capacity wound up dropping to the aforesaid ~81 kWh. Should they have 'fessed up? Probably. But it's not like that scenario has never happened before!

2. Engineer says to marketing guy: "Capacity is 81 kWh." Marketing guy has just enough smarts to know about the ~4k reserve. Without double-checking he assume engineer meant 81 kWh usable capacity, so adds 4 to 81 and comes up with the 85kWh advertised rating. Again, should they have 'fessed up? Probably. But it's not like that scenario has never happened before, either!

I seriously doubt there was anything nefarious going on with the 85 kWh claim. You'll need a smoking gun to convince me otherwise. Meanwhile, I'm not going to fret over it. My soon-to-arrive 90D whether it has 90 or 85 kWh actual capacity, will do just fine.

 

[No2DinosaurFuel]

OK I read all the post and here are my conclusions:

1) Fan-boyz: Some people are either stock holders or die hard tesla fan-boyz who see any attack on tesla as an attack on them. For these people, I recommend you look at yourself and read the thread carefully and relate to other times when companies or people have mislead you and how you felt about that experience after knowing the truth. I am not saying this is how you should view this thread but it helps to understand what the other people on the side is thinking and how they came up with their conclusions.

2) Reserve Judgement until the End: I would hold off judgment until we get some more hard data from wk057. Like everyone else, I blindly trusted Tesla's numbers, but slowly starting to doubt tesla's integrity after the P85D HP scandal. Just look at how they recently changed their advertisement on the P85D. For this thread, let's practice wait and see. So far the data does not look good, but I would like to see the complete picture before making any conclusion.

3) Cost Margins: As for those who claim tesla 85 as an 80 makes no difference in the sale numbers, I am incredulous. Here is why: would you have paid that much more for the 85KWh knowing it was 20KWh more than the 60KWh? I take it as tesla needed to advertise the higher pack as an 85KWh to entice enough people to cough up enough money to give tesla enough margins on the 85 to make it someone more feasible to manufacture. 25KWh more for X more money is a much better sell than just 20Wh more for the same X more money. It's inherent in human nature to get the most for their money. 25KWh to me is a sizable chunk increase. 20KWh is more modest. This would definitely affect my view on how much more dollars I am willing to give up to gain those extra KWh and if I am willing to make that jump. Just look at all those threads about how some people say they would pick up the 70KWh instead of the 85KWh.

4) See it from the BOTH Sides: I am curious to see what Tesla have to say about this. They would probably not respond to this.

5) Range is what I am after: I also notice a few early poster stating: "woopy do, I don't care. I bought the tesla for the range and that is what I got." For those in this category, if you are OK with being lied to, then all the more power to you. But not everyone is like you. Some are looking for other things when deciding to purchase a product. Falsely advertising the capacity will affect the true longevity of the pack as others have stated. Tesla do have their unlimited mileage warranty, but keep in mind this does not cover pack's normal degradation. Using a lower capacity pack will always have a faster degradation rate than higher pack given the same usage. But I wouldn't fault tesla too much for this because they never advertised the degradation rate.

Ideally, and I mean this is quixotic, tesla should partial refunds 85KWh pack owners. I would like Tesla to survive so I DO NOT advocate buying back the cars, free upgrades to at true 85KWh pack, or class-action because they would surely bankrupt Tesla. If this truly turns out to be lower capacity battery, I really hope tesla change their ways in how they do business.

 

[JRP3]

I'm fairly sure Tesla can just say they used the max rated numbers for brand new cells fresh off the line to come up with the 85 number and not end up doing any refunds or anything else. I say this because a cells actual capacity rating is always "squishy" and can change with temperature and discharge rates as well as number of cycles.

 

[FlasherZ]

5) Range is what I am after: I also notice a few early poster stating: "woopy do, I don't care. I bought the tesla for the range and that is what I got." For those in this category, if you are OK with being lied to, then all the more power to you. But not everyone is like you. Some are looking for other things when deciding to purchase a product. Falsely advertising the capacity will affect the true longevity of the pack as others have stated. Tesla do have their unlimited mileage warranty, but keep in mind this does not cover pack's normal degradation. Using a lower capacity pack will always have a faster degradation rate than higher pack given the same usage. But I wouldn't fault tesla too much for this because they never advertised the degradation rate.

Sorry, I don't consider it "lied to me" until I understand the reasoning for it and can verify that it is intentional / malicious. The number of kWh in the battery pack is inconsequential when the customers buy the car for miles and not kWh. Tesla doesn't advertise longevity based on the kWh in the pack - only customers are doing that based on their speculation of the technology. Tesla advertised 8 years, unlimited mileage warranty against failures, and indeed there have been some quotes about degradation. As it turns out, degradation doesn't seem to be a major problem - a local user with an "A" pack has degradation of 9-10% after 102,000 miles; my car on a 2-year-old "D" pack has degradation of less than 2% after 2 years, 50,000 miles. As you note, Tesla has made no degradation claims other than a handful of small quotes that were thrown out in Q&A sessions. Nothing official.

Ideally, and I mean this is quixotic, tesla should partial refunds 85KWh pack owners. I would like Tesla to survive so I DO NOT advocate buying back the cars, free upgrades to at true 85KWh pack, or class-action because they would surely bankrupt Tesla. If this truly turns out to be lower capacity battery, I really hope tesla change their ways in how they do business.

I don't think refunds are warranted.

It would be like buying a high-strength trash can - that trash can performed flawlessly and to its strength specifications that you needed. However, the manufacturer claimed it was built out of the new AL9000 alloy, yet as it turns out they actually used the AL8500 alloy (nevermind the reason - but let's just say for the sake of argument that at the last minute, after building all their marketing materials, that they found the AL9000 alloy had a problem). Net-net, the trash can still did what you want it to do, and it held up to the same strength. No one bought that trash can specifically because it had AL9000 aluminum in it - unless they were looking for a cheap source of AL9000 to do something completely weird, like build a solar PV system reflector out of it... the trash can did everything they needed it to do and had the necessary strength to live up to its functional claims.

Screaming for a refund because the product worked as expected but didn't have the AL9000 alloy would not be appropriate, IMO.

This is isolated from the 691 HP conversation, because in that case the car could not put down 691 HP no matter how you tried. In this case, the car *does* achieve 265 miles (or better) on an 85 kWh pack at speed limit with a mix of driving contemplated by the EPA standard. I can still do it after 72,000 miles and 3 years.

 

[Electroman]

I really don't see what the fuss is all about:

- we all bought a 265 miles range car that was named as Model S 85kWh. If they had named it as Model 300 kwH with 265 miles range I would have still bought for the same price. If they had named it as Model 50 kwH with 265 miles range I would have still bought for the same price. The consumer did not get a lesser or better car if it travels the same distance whether it is 50kWh or 300kWh. Regarding degradation, what really matters is whether it follows the same curve what Tesla has promised. We don't have to play battery scientist and start working on with cycles .vs. degradation graphs. All it matters does it degrade same or less than what Tesla has said.

- The usable capacity was already well known as 76 to 77 kWh for a long time. How does it matter how much un-usable buffer Tesla provides on top it? The buffer is there to prevent degradation. If Tesla can do it with 81 kWh, more power to them. In fact I don't care if the battery full capacity is 77 kWh and Tesla lets us use all of it as long as degradation does not happen. That is the bottom line.

wk: great work. But you come out some kind of drama queen. You don't have to provide your dramatization like, 'in my world 85 is not 81'. And your conclusions around how we got cheated on cost, is just meaningless. Remember the purpose of buying an 85 kwh battery is to drive 260 miles on a charge (on road conditions that Tesla has listed out). The purpose of upgrading 60 to 85kWh is to get an increase in range of 55 miles.

Hypothetically what if Tesla late in the product cycle just before production, discovered that 81 kWh gets you the needed range, while the literature has all been advertised as 85 kWh. Do you expect them to change the marketing literature?

 

[smac]

My 2 cents:

1Tb hard drive does not equal 1,000,000,000,000, it is 2^40 = 1,099,511,627,776.

I was always under the impression HD manufacturers used decimal kilo (1000), not base 2 "kilo" (e.g. 1024).

Why a hard drive has less storage space than promised?

 

[MP3Mike]

Hypothetically what if Tesla late in the product cycle just before production, discovered that 81 kWh gets you the needed range, while the literature has all been advertised as 85 kWh. Do you expect them to change the marketing literature?

Yes I do. I don't care what they call the model, but don't list the spec as one thing and ship something different.

What if Intel advertised a new processor as 5GHz, but just before production they found that they would get the same performance with a small change while dropping it to 4.75GHz. Would you still be OK with them advertising it as a 5GHz processor?

Tesla flat out says the battery is a 85 kWh battery, and it does not appear to be so. I would be fine if they still called it a Model S 85D, as long as the specs said it contained an 81 kWh battery. (If that is what it really is.)

 

[Electroman]

In fact the hard drive case is a clear case of deception. I have been fooled in the early days of buying 4 GB SD card thinking I can use it to copy a video file that is a few MB short of 4 GB, only to discover you only get around 3.8 GB of usable space. In that case what I am buying is the advertised storage space.

In the case of Tesla what I am buying is advertised range. Not energy storage space.

If Tesla has take the same route in Powerwalls (which is similar to hard drive in use case) then it is a different story.

 

[Mike K]

I really don't see what the fuss is all about:

- we all bought a 265 miles range car that was named as Model S 85kWh. If they had named it as Model 300 kwH with 265 miles range I would have still bought for the same price. If they had named it as Model 50 kwH with 265 miles range I would have still bought for the same price. The consumer did not get a lesser or better car if it travels the same distance whether it is 50kWh or 300kWh. Regarding degradation, what really matters is whether it follows the same curve what Tesla has promised. We don't have to play battery scientist and start working on with cycles .vs. degradation graphs. All it matters does it degrade same or less than what Tesla has said.

- The usable capacity was already well known as 76 to 77 kWh for a long time. How does it matter how much un-usable buffer Tesla provides on top it? The buffer is there to prevent degradation. If Tesla can do it with 81 kWh, more power to them. In fact I don't care if the battery full capacity is 77 kWh and Tesla lets us use all of it as long as degradation does not happen. That is the bottom line.

wk: great work. But you come out some kind of drama queen. You don't have to provide your dramatization like, 'in my world 85 is not 81'. And your conclusions around how we got cheated on cost, is just meaningless. Remember the purpose of buying an 85 kwh battery is to drive 260 miles on a charge (on road conditions that Tesla has listed out). The purpose of upgrading 60 to 85kWh is to get an increase in range of 55 miles.

Hypothetically what if Tesla late in the product cycle just before production, discovered that 81 kWh gets you the needed range, while the literature has all been advertised as 85 kWh. Do you expect them to change the marketing literature?

This. This all day long. I love that if you don't agree that the sky is falling you're labeled a Tesla apologist or fan boy. I've had vocal criticisms of Tesla on this forum but I think this is entirely a non-issue. Again, just to summarize:

1. People purchased the car based on range, not pack size.
2. Nobody would purchase the car based on pack size alone because it's a useless metric without knowing other variables.
3. Still nobody has been able to explain what Tesla has to gain from intentionally misleading people about this. If there is no motive than what's the point of committing the crime?
4. The simplest explanation is that originally they estimated the need for an 85kwh pack to achieve their mileage goals and throughout the design process then realized they could achieve these goals with a slightly smaller pack.

I swear some of you just need a reason to be upset. The internet is the place to go to find things you had no idea you were supposed to be outraged about.

 

[FlasherZ]

What if Intel advertised a new processor as 5GHz, but just before production they found that they would get the same performance with a small change while dropping it to 4.75GHz. Would you still be OK with them advertising it as a 5GHz processor?

That depends. In the early days (up through Pentium 3), MHz/GHz was *the* representation of the performance of the processor and used/cited by customers as their benchmark, and therefore I would not be ok with it.

Today, to a consumer, GHz is fairly meaningless and only works in comparison with other models, and the performance benchmark is something else - whether GFLOPS, BogoMIPS, or whatever. If the manufacturer met the benchmark spec but at a lower clock rate, then it might not be a big deal.

No one likes to see incorrect specs, but I run across them daily - for whatever reason. Most of the time it's due to specs changing at the last minute - chipsets being unavailable or whatever. Some are material and violate the warranty of fitness for a particular purpose. Others are not and do not.

 

[Mike K]

What if Intel advertised a new processor as 5GHz, but just before production they found that they would get the same performance with a small change while dropping it to 4.75GHz. Would you still be OK with them advertising it as a 5GHz processor?

For years Ford called their 302 V8 the 5.0 despite displacing just 4.9 liters. Nobody cared. Why? Because the car met the performance numbers Ford advertised.

 

[Electroman]

Yes I do. I don't care what they call the model, but don't list the spec as one thing and ship something different.

What if Intel advertised a new processor as 5GHz, but just before production they found that they would get the same performance with a small change while dropping it to 4.75GHz. Would you still be OK with them advertising it as a 5GHz processor?

Tesla flat out says the battery is a 85 kWh battery, and it does not appear to be so. I would be fine if they still called it a Model S 85D, as long as the specs said it contained an 81 kWh battery. (If that is what it really is.)

You are wrong here. The 5GHz you refer to is a just a means to get the CPU performance which is measure in MIPS. If a specific processor is advertised as 10 MIPS, that is what you are buying. You can't take Intel to task for designing their processor to run at a slower speed, as long as they meet their MIPS.

The cycle speed is only used as a comparative indicator between two model of the same processor family. a 5GHz processor will be faster than a 4GHz - but not necessarily proportionately faster by 5/4th. Whereas 15 MIPS is expected to be 50% faster than 10 MIPS processor of the same family (for identical computational workloads)

 

[freeewilly]

But, just based on the range numbers, I highly doubt the 90 pack is really a 90 kWh pack. My money is on ~85kWh, minus a 4 kWh anti-brick buffer, for ~81 kWh usable. (Edit: Reasoning: 85D's are rated at 270 miles, your 90D is showing 282 miles. 282/270 = 1.04444x capacity. 1.04444 * 77 kWh, usable capacity of the "85"'s, = ~80.42 kWh ... + ~4.25 kWh anti brick buffer (guestimate) = ~85 kWh. So, I'm thinking the 90's are actually the true 85 kWh packs)

You forgot to add the 12v battery :tongue:

 

[Max*]

I was always under the impression HD manufacturers used decimal kilo (1000), not base 2 "kilo" (e.g. 1024).

Why a hard drive has less storage space than promised?

I think you're both saying the same thing, but in different ways.

 

[freeewilly]

I really don't see what the fuss is all about:

This is a great thread, there is no fuss about it. wk tests on Tesla batteries and he did his best to provide accurate data. And I don't see anyone attacking anyone...... yet.
Bunch of people want to know every bit of our car and how EV battery works.

 

[Cottonwood]

I was always under the impression HD manufacturers used decimal kilo (1000), not base 2 "kilo" (e.g. 1024).

Why a hard drive has less storage space than promised?

This gets even more confusing because RAM and Flash Drives are sold in the binary equivalents while hard disks are sold in decimal values.

This is mostly because RAM and Flash memory sizes usually grow in factors of two as address bits are added, while hard drives grow incrementally as the manufacturers figure out how to squeeze more bits on the platter(s). Few people want to deal with buying 1.074 Gig of RAM; 1 Gig is much simpler, but if a hard disk can claim 10% more advertising capacity...

It is all specsmanship and advertising for hard disks.

• 1 Kilo: 2[SUP]10[/SUP] is 2.4% more than 10[SUP]3[/SUP]
• 1 Mega: 2[SUP]20[/SUP] is 4.9% more than 10[SUP]6[/SUP]
• 1 Giga: 2[SUP]30[/SUP] is 7.4% more than 10[SUP]9[/SUP]
• 1 Tera: 2[SUP]40[/SUP] is 10.0% more than 10[SUP]12[/SUP]
• etc...

 

[Matias]

What if one discharges 85 pack cells with very low (like 0.01C) rate? Would that give 85 kWhs?

 

[sierra]

...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).

"Batteries degrade not only during cycling, but also during storage. This makes cycle number a rather uncertain estimate of effective battery age in view of its performance.
Degradation with storage is highly dependent on storage conditions, mostly voltage and temperature. Fig. 10 shows degradation of Li-ion battery capacity with storage at different temperatures."

(

see http://focus.ti.com/download/trng/d...ety and Monitoring in Mobile Applications.pdf)

How old are these Tesla batteries?

 

[scaesare]

"Batteries degrade not only during cycling, but also during storage. This makes cycle number a rather uncertain estimate of effective battery age in view of its performance.
Degradation with storage is highly dependent on storage conditions, mostly voltage and temperature. Fig. 10 shows degradation of Li-ion battery capacity with storage at different temperatures."

(View attachment 110200

see http://focus.ti.com/download/trng/d...ety and Monitoring in Mobile Applications.pdf)

How old are these Tesla batteries?

That's an interesting graph... at the lower temp range (moderate average temps in many locations), it implies that storing batteries at a higher SoC (~100%) is better for their health...

That's counter to the commonly accepted wisdom around here.

 

[SteveG3]

based on an Elon Musk comment (I believe about a year and a half ago), since the Model S was introduced in 2012, the vehicle has dropped a few hundred pounds. what's more, there has been a series of different battery packs.

isn't it possible that,

-the early 2012 Model S were built to use XY kWh of a battery pack that really was 85 kWh, as Tesla determined that XY kWh usable got them to a range that would hit an EPA number (265 miles) they selected for the biggest battery.
- as battery chemistry and/or pack design, management was tweaked, and weight came off the car from continual changes across the design of the car,
1. lower weight meant that a usable capacity lower than XY kWh was sufficient to deliver the same range as the original battery pack that actually had 85 kWh
2. newer battery chemistries came with improvements that allowed Tesla to increase the percentage of the battery pack available to use
- over time, these changes would mean that Tesla went from an 85 kWh battery pack to various small changes up through the one you tested and measure as 81 kWh. they didn't change the Model S 85 kWh offering to say, an 83.6 kWh Model S, then an 82.9 kWh Models S, etc... but rather knew they were delivering the same range as the original 85 kWh battery.

just to say, having spent all of ten minutes thinking about it (and not even having the knowledge to consider possible errors in your testing or calculations), there may be other explanations to this. not saying I disagree with your posting this, and raising questions.

update: re point 2 above... more broadly, a variety of potential changes to the battery pack, whether a newer cell chemistry, newer battery management, cooling, or other, that allowed Tesla to feel confident making a larger percentage of the pack available for use in propelling the car. what letter battery pack are we up to now since the original "A" pack? clearly there have been changes, and there may well have been changes allowing more of the battery to be safely used.

wk057, when you return, please respond to what I posted above a few hours after your original post.

if your analysis is correct, and if it is due to a scenario like I suggested, it would also answer the "why would Tesla do this?" question...

I think one could see why a company with a new technology, actively being challenged in the public discourse by those with the incumbent technology (with intense media attention, often indifferent to the facts), would not want to offer the public something like:

July 2012-January 2013: The Model S 85 or 60

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

if the battery size was just a number in a spec sheet, they could have done this... but from the beginning of the car's launch, Tesla used the battery size as part of the car's name (badging), and the range did not change.

I totally get why people feel the way they do about the horsepower issue. I totally get why you did this research and would want to share it. maybe this is something similar, maybe it is not. I don't think we have enough information at this point to really know what happened and decide whether we think it was reasonable or stepping on the consumers.