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

[Max*]

Here is another check supporting at least one of wk057 data points.

When my Sig P85 was new, I worked very hard to find out what Wh/mi would equal the rated mile in the display. After many drives that came out to 290 Wh/rated mile.

If you use wk057's number of 77 kWh usable in a pack and divid that by the EPA range of the original P85, that comes out to 290.6 Wh/rated mile. My 290 Wh/rated mile and wk057's 77 kWh/265 rated miles = 290.6 Wh/rated mile in a new pack are remarkably consistent numbers.

I had this discussion with someone (AWDTesla maybe?) in an other thread compared rated miles to EPA projections on the 70D vs. P90DL.

On my 70D, in order to get the "projected" range to match up with rated range, I need to be somewhere in the 288wh/mi territory. EPA says 240 miles for the 70D, that would mean the usable battery in the 70D is ~69kwh.

Maybe the 90D is really 90kwh now? (not to you, just a general question)

 

[Pruitt]

I posted (back on page 9) a couple of explanations I think are at least plausible. After some further thought, here's what I think is the most likely explanation for the discrepancy in advertised power vs. actual power:

The designed "ideal" battery pack, under ideal conditions, would theoretically store about 85 kWh (maybe 84.5 or 85.1 or something like that). The actual packs built are not ideal, so they store something somewhat less than that. So the marketing department advertises the ideal, rather than the real-life, capacity. Not a conspiracy to deceive at all - that sort of thing happens all the time.

Meanwhile, what an entertaining thread this is!

 

[JRP3]

I'm not sure that's a marketing mistake. if they saved $1,000 per vehicle by dropping about 4 kWh that's about a one point increase in their gross margins (something Wall Street is intensely focused on), while raising range a few miles every 6-9 months could actually make consumers more likely to hold off on buying a Model S. we could debate whether which would be better (raise the range or raise Tesla's margins), but I don't think it's anywhere close to being an obvious mistake that makes the idea they would do it implausible.

Then why didn't they do the same thing with the 60, and in fact since the 60 is slightly more than 60, that means they did the opposite?

 

[SteveG3]

Then why didn't they do the same thing with the 60, and in fact since the 60 is slightly more than 60, that means they did the opposite?

what was the proportion of orders? about 7 to 1 for the 85 in favor of the 60. what's more, the delta on the 60 is about 1/4 that of the 85, so overall about a 28 to 1 ratio of benefit to loss. quite the net gain.

 

[JRP3]

So your claim is now that they were using different cell chemistry in the 60 and 85, using better energy density cells in the 85 to reduce weight, but not in the 60. Unlikely at best.

 

[SteveG3]

So your claim is now that they were using different cell chemistry in the 60 and 85, using better energy density cells in the 85 to reduce weight, but not in the 60. Unlikely at best.

I'm not sure what you are basing that assertion on. I'm saying, with lower weight, they may have reduced the size of the 85 kWh pack... I'm not making any assertions about how they might have chosen to do that. it's also possible the discontinued 60 kWh Model S also had about 2 or 3 miles more range than advertised because on net, it was better to not change that rating and proceed with the 85 kWh badging, and gain in margins.

 

[wk057]

You keep making this claim that some small % of weight loss can offset the loss of 4 kWh. Where's your data to support this? Again, as an owner of two Model S and the previous owner of a 3rd, I know for sure that the weight loss would not be the same as 4 kWh, and I'm certain other owners would concur. If so, then driving around with a couple of people in the car would cost 4 kWh of power vs just a driver. This just isn't the case.

Please return when you have data to back up your claims. I'm not going to waste any more time debating the point until then.

 

[supratachophobia]

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?

To that argument, I would say that 265 miles on a charge is at best, wishful thinking. With temperature being such a factor, none of us have ever seen close to 265 in the real world. And extra 4kw would have actually allowed almost everyone to get that number.

 

[AWDtsla]

Here is another check supporting at least one of wk057 data points.

When my Sig P85 was new, I worked very hard to find out what Wh/mi would equal the rated mile in the display. After many drives that came out to 290 Wh/rated mile.

If you use wk057's number of 77 kWh usable in a pack and divid that by the EPA range of the original P85, that comes out to 290.6 Wh/rated mile. My 290 Wh/rated mile and wk057's 77 kWh/265 rated miles = 290.6 Wh/rated mile in a new pack are remarkably consistent numbers.

Right. The car doesn't claim more than 77kWh usable. The 90's don't claim more than 83kWh usable either. All the math works up looking at the advertised rated miles in the 85's and 90's. In the 60's and 70's it gets more interesting.

It's almost the same deal as the HP issue. You get in the car, the car tells you exactly how much power it's delivering, but it doesn't nearly match the published spec. In this case the rated usage times displayed rated miles is the usable capacity, it's simple math.

 

[supratachophobia]

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.

Good theory, but his cells are from an A/B pack, the first Model S's off the line.

 

[rage_777]

I'm not sure what you are basing that assertion on. I'm saying, with lower weight, they may have reduced the size of the 85 kWh pack... I'm not making any assertions about how they might have chosen to do that. it's also possible the discontinued 60 kWh Model S also had about 2 or 3 miles more range than advertised because on net, it was better to not change that rating and proceed with the 85 kWh badging, and gain in margins.

So are you saying that as the decreased weight, they started removing cells from the battery pack? Or that by removing some cells they started saving weight? If that's the case, then you are saying that to prove your theory somebody should just do a cell count on an early 85 pack and a later 85 pack and they should be different? Wouldn't it be a lot easier and cheaper to just leave those cells in the pack and have more Wh added to the pack?

Not sure what all the fuss is really about. wk is just saying that if they would have said from the beginning we have an 80 kWh pack, nobody would have cared and the car was great either way. So why say it's an 85 kWh pack and you can't get to 85 kWh even under ideal conditions. Just like the 0-60 numbers who cares if it involves the 1 foot roll out, it is still fast as heck. Or the 691 hp number, it's still fast and doesn't matter what the number is. You could say it is a 20 hp car, does it really matter? Why overstate something that doesn't need to be overstated?

 

[AWDtsla]

I had this discussion with someone (AWDTesla maybe?) in an other thread compared rated miles to EPA projections on the 70D vs. P90DL.

On my 70D, in order to get the "projected" range to match up with rated range, I need to be somewhere in the 288wh/mi territory. EPA says 240 miles for the 70D, that would mean the usable battery in the 70D is ~69kwh.

Maybe the 90D is really 90kwh now? (not to you, just a general question)

Right. The 70D seems to say 290 Wh/mi, but 240*.290=69.6kWh!!! So either 70D's are getting a smoking deal, or one of those numbers is wrong, or both.

But no, the 90 is NOT a 90. It's an 83.

 

[MP3Mike]

But no, the 90 is NOT a 90. It's an 83.

Ouch. Where are you getting the 83 number from?

Tesla states ~6% more range for the 90, which assuming that the 85 is really 81 would be 85.9 kWh. If it is really only 83 kWh then you are only getting a ~2.5% boost in capacity, and getting "cheated" out of ~3 kWh...

 

[AWDtsla]

Ouch. Where are you getting the 83 number from?

Tesla states ~6% more range for the 90, which assuming that the 85 is really 81 would be 85.9 kWh. If it is really only 83 kWh then you are only getting a ~2.5% boost in capacity, and getting "cheated" out of ~3 kWh...

From the car. ~267 miles at 100%, ~310 Wh/mi, that's ~83kWh. BTW, 83 kWh is almost 8% more than 77 kWh, a number which factored into my decision to get a 90. So none of this was ever a secret, at least to me.

edit - and usable is the only thing that matters to me. 81kWh means nothing.

 

[MP3Mike]

From the car. ~267 miles at 100%, ~310 Wh/mi, that's ~83kWh. BTW, 83 kWh is almost 8% more than 77 kWh, a number which factored into my decision to get a 90. So none of this was ever a secret, at least to me.

OK, so you are saying 83 kWh of usable energy, not total. Add in the 4 kWh anti-brick buffer in and you actually got a 87 kWh battery. Which sounds much better.

Of course maybe they shrunk the anti-brick buffer a little, so maybe it is an 86 kWh battery with a 3 kWh buffer.

 

[tezzla]

I wonder if there are people on the VW website (still) arguing that VW didn't cheat either?

 

[redevries]

I wonder if there are people on the VW website (still) arguing that VW didn't cheat either?

Considering the 2015 sales figures in Europe, there are a lot of people who really don't care.

 

[Grendal]

I wonder if there are people on the VW website (still) arguing that VW didn't cheat either?

That is a ridiculous comparison. There is a huge difference between intentionally cheating their buyers and having an advertising "number." The reality is that battery storage is not an exact science. You can create fluctuations based on a large number of factors. Even the same type of battery will have variations from battery to battery. This is well within the normal parameters of doing business. If Tesla secretly had an ICE tucked into the car then that would be the equivalent to what VW did.

 

[glhs272]

Keeping it in perspective... from what it seems, we are getting really upset because Tesla gave the 60kwh cars too much battery capacity.

I hate it as much as the next guy, but it seems the automotive industry wants to advertise battery nameplate capacity and not actual usable capacity. I wish it weren't that way, but it is. Tesla has to operate in this environment, and so it seems they decided to do what all of the other guys have done and advertise nameplate (i.e. meaningless) capacity.

For example:

A BMW i3 is advertised as 22kwh battery with actual usable capacity of 18.7 kwh, thus only 85% of nameplate capacity is available to the owner.

A Nissan leaf is advertised as a 24kwh battery with only 21.3kwh actually usable, thus 88.8% of nameplate capacity is available to the owner.

A Tesla Model S85 has an advertised battery of 85kwh with only 77.5kwh actual usable, thus only 91.2% of nameplate capacity is available to the owner.

A Tesla Model S60 has an advertised battery of 60kwh with only 56.0kwh actual usable, thus only 93.3% of nameplate capacity is available to the owner.

It seems that is the rub here; 1) Tesla is marketing bogus capacities just like all the other car companies and 2) Tesla used less bogus numbers on the 60 than the 85.

There may have been marketing reasons for Tesla to use different bogus numbers for the 60 vs. 85, such as to push people to buy the 85 vs. the 60. Or there may have been technical reasons for giving more battery (less bogus) to the 60, such as making supercharging even more painfully slow if they didn't. I don't know what motivates them. But, it seems what Tesla has done is make more capacity available to the owner than any other car manufacturer is (I haven't looked them all up, but still).

My 2 cents is all manufacturers should be forced to report actual usable battery capacity on the window sticker, regardless of what marketing has called it. Perhaps someday we will get that. But until all of the car companies are forced to use real specs, we will likely continue to see these games being played on the unknowing consumer.

 

[AWDtsla]

OK, so you are saying 83 kWh of usable energy, not total. Add in the 4 kWh anti-brick buffer in and you actually got a 87 kWh battery. Which sounds much better.

Of course maybe they shrunk the anti-brick buffer a little, so maybe it is an 86 kWh battery with a 3 kWh buffer.

It could be 0.5kWh reserve and a 83.5kWh battery pack, for all we know.