Upgrade for 90 limited "A Packs" : Official answer from Jerome Guillen, VP WWSS TM

[Norbert]

These descriptions of Model S are incompatible with my car's actual behavior:

Tesla's website generally does not show historical information. This is common practice, on any website I'm familiar with, and most products change over time, in one way or another.

This specific page doesn't even show the numbers for the 60 kWh version (or the 40 kWh version), in so far as different. Also, when features of the Model S are updated, Tesla does not in general send out notifications, we just often happen to notice the updates on the website.

 

[Zextraterrestrial]

A vs B pack supercharge

Since this thread is 'newer' - I had my A replaced with a refurb B pack. but firmware 5.9 on the B vs 5.8 on the A pack so it makes it a little tricky to compare directly. I did end at the same SOC and start at about the same SOC

A pack: 11% SOC - 9mi rated
chg to 84% SOC - 197mi rated

charged between 85-90kW for ~ 18.5 minutes (90 peak ~ 14 min)

55.6 minutes total (188 mi)

B pack: 10% SOC - 28 mi Rated
chg to 84% SOC - 223mi rated

charged above 90 kW for ~ 18 min (110-12 peak ~ 8+min)

47.5 minutes total (195 mi) (last 2 min from 218-223, so ~45.5 min for 188mi added)

so here is an interesting part of it...

kW on X-axis

different charge rate MPH for the same kW input...? due to Amperage differences I assume. the most the 'A' takes that I have seen is 250A. B pack pulls >315A

 

[Cottonwood]

Since this thread is 'newer' - I had my A replaced with a refurb B pack. but firmware 5.9 on the B vs 5.8 on the A pack so it makes it a little tricky to compare directly. I did end at the same SOC and start at about the same SOC

...

different charge rate MPH for the same kW input...? due to Amperage differences I assume. the most the 'A' takes that I have seen is 250A. B pack pulls >315A

Remember that while kW, Amps, and Volts are nearly instantaneous reported values, mph charge rate is the average of the charge session. For example, your "B" graph shows an "mph" charge rate of 250 mph with a power of about 40 kW; on an instantaneous basis this is just not possible; 40kW=>about 133 mph charge rate.

Your curves of rate of charge vs kW are at most a curiosity, because you are plotting an average for the session (mph) against an instantaneous value (kW).

 

[Zextraterrestrial]

I was thinking the MPH reported is instantaneous just like the kW. just different in that you can 'see' either one by selecting it in settings. I thought this is where the numbers are coming from for these 2 values.

how did you determine
40kW ~ 133mph charge rate? based on rated power used per mile?

 

[ken830]

I see no possible argument for "bad faith" here. They sold someone a car with an "A" battery, which was the best/only pack they had available at the time.

Actually, there are hundreds (thousands?) of late production vehicles that shipped with A packs despite better tech being available.

An entire week of re-hashing some of the same arguments... and only ONE post mentioned the April-built 85kWh cars that has "A" packs when the "B" packs have been delivered for months before that. No matter what your stance is on early cars with "A" packs, I think everyone is in agreement that the April-2013 cars with A packs is a big W-T-F! But we always seem to be forgotten. Even Jerome's email to us did not acknowledge our situation at all....

 

[Norbert]

An entire week of re-hashing some of the same arguments... and only ONE post mentioned the April-built 85kWh cars that has "A" packs when the "B" packs have been delivered for months before that. No matter what your stance is on early cars with "A" packs, I think everyone is in agreement that the April-2013 cars with A packs is a big W-T-F! But we always seem to be forgotten. Even Jerome's email to us did not acknowledge our situation at all....

Panasonic may have been producing both A packs and B packs for some time, due to multiple production sites or lines. After converting (or adding) the first site or line, it may have took them a few months to convert (or replace) the other site or line. And Tesla may not have been able to say "no" to those A packs still coming in, since they accepted them to start with (that being a time when Superchargers where specified to be 90 kW).

 

[apacheguy]

@Zextraterrestrial - Very nice and thanks for posting. Although I agree that it is difficult to compare. What I was most interested in was the fact that you spent 18 minutes above 90 kW! Starting from the same SOC (10%), my car only spends 14 minutes at 90 kW before beginning its taper at ~35% SOC. Would you mind plotting power (kW) vs. SOC (%) on the same graph so we can get a sense of the taper curve differences?

 

[Cottonwood]

I was thinking the MPH reported is instantaneous just like the kW. just different in that you can 'see' either one by selecting it in settings. I thought this is where the numbers are coming from for these 2 values.

how did you determine
40kW ~ 133mph charge rate? based on rated power used per mile?

YMMV, but every time that I have checked, the MPH reported was the average over the session. Take the plot into the taper and this becomes very obvious.

Every time that I have looked at rated miles accumulated in the battery with DC charging on a Supercharger, it has been very close to 300 Wh/(rated mile). Before 5.9, whenever my "since last charge" Wh/mi was at 290 Wh/mi, the miles traveled + rated miles left was equal to the rated miles that I started with. My guess is that the difference between these two figures of 10 Wh/mi is due to DC charging inefficiency. Note that AC charging efficiency is a lot worse because of the losses in the AC/DC conversion in the charger.

40 kW divided by 300 Wh/mi is equal to 133.3 MPH.

 

[Norbert]

@Zextraterrestrial - Very nice and thanks for posting. Although I agree that it is difficult to compare. What I was most interested in was the fact that you spent 18 minutes above 90 kW! Starting from the same SOC (10%), my car only spends 14 minutes at 90 kW before beginning its taper at ~35% SOC. Would you mind plotting power (kW) vs. SOC (%) on the same graph so we can get a sense of the taper curve differences?

When plotting power over time, it looks as if the differences (between A pack and B pack) after the first 15 min are quite small. A plot over SOC would indeed be interesting.

 

[Lloyd]

Over the length of the SOC, starting both at 28 miles, it appears to me that Julian was right in that there is about a 4 minute difference between A and B.

 

[ken830]

Panasonic may have been producing both A packs and B packs for some time, due to multiple production sites or lines. After converting (or adding) the first site or line, it may have took them a few months to convert (or replace) the other site or line. And Tesla may not have been able to say "no" to those A packs still coming in, since they accepted them to start with (that being a time when Superchargers where specified to be 90 kW).

This mixing theory is only evident in December 2012. It doesn't hold true after that -- And that's the problem with the late vehicles with "A" batteries. I know the battery wiki isn't a huge sample, but the last recorded "A" battery was VIN 25xx (December 2012) in the early batch of cars. All cars following that was 100% "B" batteries. The next "A" battery didn't show up until VIN 72xx (March 2013). From there, 100% of the reported batteries were "A" until VIN 94xx (April/May 2013). From there, 100% of the reported batteries were "B".

There is a clear chunk of cars (VIN 72xx - 94xx) that had (most likely) 100% "A" batteries despite months of 100% "B" battery deliveries prior to this. Now the question is where did these come from? Are they refurbished batteries from early cars? Did they just find a batch of cells that were forgotten in a corner somewhere for months? What happened? Why?

 

[Norbert]

This mixing theory is only evident in December 2012. It doesn't hold true after that -- And that's the problem with the late vehicles with "A" batteries. I know the battery wiki isn't a huge sample, but the last recorded "A" battery was VIN 25xx (December 2012) in the early batch of cars. All cars following that was 100% "B" batteries. The next "A" battery didn't show up until VIN 72xx (March 2013). From there, 100% of the reported batteries were "A" until VIN 94xx (April/May 2013). From there, 100% of the reported batteries were "B".

There is a clear chunk of cars (VIN 72xx - 94xx) that had (most likely) 100% "A" batteries despite months of 100% "B" battery deliveries prior to this. Now the question is where did these come from? Are they refurbished batteries from early cars? Did they just find a batch of cells that were forgotten in a corner somewhere for months? What happened? Why?

I don't see how it could be possible to find a definite answer, but I think it just means that it was more complicated than the potential situation I described. My first guess would be that Panasonic had some difficulties producing "B" cells, between December 2012 and March 2013, assuming your numbers are correct. I guess B cells use either a slightly different chemistry, or a slightly different manufacturing method. In the latter case, for example, they might have used more delicate machinery, and it kept breaking (just a random speculation). In any case, I'm speculating that at that time, Tesla had no sufficient reason to reject those cells. It would be one of the cases where cutting edge technology sometimes needs to make step back before making two forward. In general, I don't see manufacturers providing that level of detailed information to their customers, as long as the product meets the published specifications at the time. Additionally, they might have been very hopeful that they could later raise the charging rate even for the "A" cells. It appears that turned out to be a matter of balancing multiple priorities, later on.

 

[tomas]

Y'know, all the conjecture about how/why really doesn't matter. It happened! B or later pack owners by and large can't understand the issue. Not all, but large % of A pack feel they got a raw deal on the issue. Concern has been registered with Tesla, who understand it and have proposed their path forward - eventual battery upgrade program. So, everything else is academic.

What the B or later owners should think about before they post on this topic: A owners are trying to step back from this and wait patiently for opportunity to upgrade (which is quarters if not years out), but we get to relive the whole painful thing every time there's a new thread and a bunch more forum members decide to wade in and opine on it.

So, have a heart and stop tormenting your forum mates!

 

[apacheguy]

Over the length of the SOC, starting both at 28 miles, it appears to me that Julian was right in that there is about a 4 minute difference between A and B.

Have to be careful when looking at rated miles. Also, bluetinc has empirical data showing > 4 min difference. A lot of folks at Tesla don't even believe that Jerome's assertion is correct.

 

[Zextraterrestrial]

Have to be careful when looking at rated miles. Also, bluetinc has empirical data showing > 4 min difference. A lot of folks at Tesla don't even believe that Jerome's assertion is correct.

ya not quite right.

40.90 minutes from 25% -84% 155 mi added for 'B' pack
vs
46.98 minutes from 27% -84% 149.5 mi added for 'A' pack

seems more like 6-7 minutes at this SOC for my car and batteries
quite a bit more when you are trying to get to 98%SOC or so on an 'A' pack. the B pack seems to take more power at higher SOC


and kW vs SOC:

 

[bluetinc]

Zextraterrestrial,

I thought that you had mentioned that some of your data is with 5.8 and some is with 5.9. If so, have you adjusted your data to account for the differences in both SOC and rated miles between versions?

Peter

 

[Zextraterrestrial]

Zextraterrestrial,

I thought that you had mentioned that some of your data is with 5.8 and some is with 5.9. If so, have you adjusted your data to account for the differences in both SOC and rated miles between versions?

Peter

no. but I don't think it should matter for the kW vs SOC graph? I know the SOC to rated numbers are different and your lines are pretty close to what I saw for 5.8 & 5.9

comparing added miles should be similar even though the rated mi # shown is higher at the same SOC for 5.9

 

[Norbert]

Y'know, all the conjecture about how/why really doesn't matter. It happened! B or later pack owners by and large can't understand the issue. Not all, but large % of A pack feel they got a raw deal on the issue. Concern has been registered with Tesla, who understand it and have proposed their path forward - eventual battery upgrade program. So, everything else is academic.

We'll have similar situations in the future, as battery cells will be improved continuously, and Supercharger rates will be upgraded sooner or later. Imagine 30,000 owners getting into that situation. Also, discussion about the reasonable price for such an upgrade will be unavoidable, once it comes to that point.

What the B or later owners should think about before they post on this topic: A owners are trying to step back from this and wait patiently for opportunity to upgrade (which is quarters if not years out), but we get to relive the whole painful thing every time there's a new thread and a bunch more forum members decide to wade in and opine on it.

These threads seem to be kept going very much by those who are part of the discussion since the beginning. And that's what has to happen when such threads go on forever: others will come in, hoping that their input will help resolve the matter.

- - - Updated - - -

seems more like 6-7 minutes at this SOC for my car and batteries
quite a bit more when you are trying to get to 98%SOC or so on an 'A' pack. the B pack seems to take more power at higher SOC

Just to mention it, also possible that there are incremental differences within the A pack designation and the B pack designation (and later), i.e. the numbers aren't necessarily the same for all cars "A" vs all cars later than "A".

and kW vs SOC:

Thanks for the graphs!

- - - Updated - - -

Plus, the numbers are likely weather/temperature dependent, to some degree.

 

[apacheguy]

Just to mention it, also possible that there are incremental differences within the A pack designation and the B pack designation (and later), i.e. the numbers aren't necessarily the same for all cars "A" vs all cars later than "A".

Im beginning to believe this to be the case as well. As you can see from Z's graph, the A pack began its taper from 90 kW at 45% SOC. On two separate occasions that I have recorded, my car begins the same taper at 35 %. We tried to work through this a couple months ago in the other thread, but we were ultimately unable to explain it. Any other Sigs want to post a taper curve (kW vs SOC) so we can try to determine whether there is a difference among A packs?

 

[Rodolfo Paiz]

Y'know, all the conjecture about how/why really doesn't matter. It happened! B or later pack owners by and large can't understand the issue. Not all, but large % of A pack feel they got a raw deal on the issue. Concern has been registered with Tesla, who understand it and have proposed their path forward - eventual battery upgrade program. So, everything else is academic.

What the B or later owners should think about before they post on this topic: A owners are trying to step back from this and wait patiently for opportunity to upgrade (which is quarters if not years out), but we get to relive the whole painful thing every time there's a new thread and a bunch more forum members decide to wade in and opine on it.

Tomas, I think you need to realize that you take things more personally and more emotionally than most people. And that's OK, in fact I think that's an asset in this life... but I suggest you are generalizing too much from your own feelings/perceptions to those of everyone else. What do you call a "large % of A pack owners", for example? 30%? 60%? Because I strongly doubt that more than 20% of those owners even know they have an A pack. I can tell you that I have a March '13 P85, and that I'm more than a little OCD about many things (esp. wrt my car) so most drivers know far less about their vehicles than I do... and I have no idea whether I have an A or a B pack, and I don't care. I suspect that most A-pack owners don't care either.

That doesn't diminish your concern. Even if the fraction of A-pack owners who really care about the issue is as low as 5%, y'all are fully entitled to feel that way and to make those feelings known to Tesla. I'm glad to see that there appears to be progress on a resolution, too. I just think you're over-dramatizing this.