Pack Performance and Launch Mode Limits

[RAW84]

Sorry for being a Johnny come lately, but does this apply to the P85D?

 

[bhzmark]

Last night I started reading about the 2017 Porsche 911 turbo to replace my p90d when my lease is up. Looks good... Faster than the p100d and an unlimited number of uses of launch control...

If you buy a used one be sure to check the Porsche counters to see how enthusiastically it was driven. Buyers Guide to Used Porsches

 

[n2mb_racing]

If you buy a used one be sure to check the Porsche counters to see how enthusiastically it was driven. Buyers Guide to Used Porsches

Useful! Thanks.

 

[St Charles]

Last night I started reading about the 2017 Porsche 911 turbo to replace my p90d when my lease is up. Looks good... Faster than the p100d and an unlimited number of uses of launch control...

My first thought on this when I read it was "yeah but then you'd have to pay for all this maintenance". Then it hit me that Teslas really do need maintenance as well. We know this because this damn limiter. But "Teslas don't need service" so we don't have any options. Even if they did the parts that would need replacing are soo hard to get to that it's likely not something a SC could do in house.

Maintaining a performance vehicle at performance levels is expensive. Clearly, Tesla is no exception to this regardless of what the CEO tweets. If Tesla is reading this, I would pay into a program to maintain my car through performance driving scenarios.

 

[sorka]

Sorry for being a Johnny come lately, but does this apply to the P85D?

No the P85D is 1300 amps.

If you mean the P85DL which is upgraded to 1500 amps, then I think the conclusion so far is this is not effected. If it were, they would essentially be eliminating your Ludicrous upgrade after some number of launches.

Now I've never actually used launch mode more than twice as it didn't improve my 0-60 numbers but I've done full power 0-60 accelerations 500+ times by now and I'm still pulling 1500 amps.

 

[smac]

My first thought on this when I read it was "yeah but then you'd have to pay for all this maintenance". Then it hit me that Teslas really do need maintenance as well. We know this because this damn limiter. Even if they did the parts that would need replacing are soo hard to get to that it's likely not something a SC could do in house.

On the other hand the depreciation on 911s is probably slightly better, so running costs overall are likely similar.

Of course comparing a 2+2 sports car against a 4 door sedan is somewhat moot. (Though no doubt there is a lot of cross selling vs the 911 turbo, on benchmark numbers, though I think that's missing the point of both tbh)

 

[AWDtsla]

If you buy a used one be sure to check the Porsche counters to see how enthusiastically it was driven. Buyers Guide to Used Porsches

This is not the same thing at all... and shame on you for make it trying to seem like it is.

You want to long explanation of why it's easy to avoid bouncing off the rev-limiter and incorrectly downshifting causing over-revs in an ICE car? Yet every time you touch the throttle on a P*D you're potentially devaluing the car?

 

[St Charles]

On the other hand the depreciation on 911s is probably slightly better, so running costs overall are likely similar.

Of course comparing a 2+2 sports car against a 4 door sedan is somewhat moot. (Though no doubt there is a lot of cross selling vs the 911 turbo, on benchmark numbers, though I think that's missing the point of both tbh)

I don't think Porsche depreciates any better or worse than Tesla. I would say that it's probably easier to resell a Porsche than a Tesla.

 

[sorka]

This is what he was tweeting to Spiegel. Beware of Snakes (shorts) in the weeds.

Did my post make it in one of his tweets? Hope not.

 

[St Charles]

This is not the same thing at all... and shame on you for make it trying to seem like it is.

You want to long explanation of why it's easy to avoid bouncing off the rev-limiter and incorrectly downshifting causing over-revs in an ICE car? Yet every time you touch the throttle on a P*D you're potentially devaluing the car?

Every time we *touch* the pedal. Come on man, that's hyperbole. We don't know the extent of what happening beyond a few measurements and some talk.

 

[smac]

I don't think Porsche depreciates any better or worse than Tesla. I would say that it's probably easier to resell a Porsche than a Tesla.

The market here (uk) is a bit mixed up at the moment. Some of the limited run cars, notably anything out of the GT stable are fetching crazy money, well above retail.

 

[jaguar36]

Every time we *touch* the pedal. Come on man, that's hyperbole. We don't know the extent of what happening beyond a few measurements and some talk.

That is what one of the biggest issues is. Tesla hasn't said if its everytime you touch the pedal or if its only launch mode or what. They haven't really said anything. If they would just come out and say exactly what happens under what conditions it would clear alot of this up.

 

[sorka]

Can someone put an asterisk(*) in the title of the thread

 

[scaesare]

My theory about individual cell fuse link fatigue was based on work wk057 did years back. Just for grins, I went back and dug up one of the posts. Reading this and assuming the cell interconnect wire diameter was not changed, you can see problems with 1600+ amps coming like a freight train!

#41
which references
#534
"I finally got around to doing some testing of the cell level fuses using a power supply and my DC electronic load.

I was able to get them to carry 24A for 60 seconds+ and they would consistently pop within a second or two at 25-25.5A.

Honestly, that's more power than I had figured they were able to handle. Assuming they're sized for 25A, that's 90W per cell, almost 40kW per module, or close to 8C max before consistent popping.

Using an NEC-style 25% margin gives me a constant current draw of about 19A possible before popping fuses. That'd be about 6C, or about 485kW nominal for an 85kWh pack."

That was July 18, 2015!!!!!!!
Now it is worth noting that the 90 pack has slightly less voltage sag than the 85 WK was testing cells from so it MIGHT be possible to get 500 KW from a 90 pack without exceeding the normal 25% constant current margin limit.

Ah very good. I was thinking about these numbers as well.

We know that the 90kW packs still have the same 96s74p cell arrangement (it wasn't until the 100's that they physically stuffed more cells in to the pack). Thus at 1,600A each cell is supplying 21.6A, which is what it's fusible link must deal with.

If wk057's assumption that they are rated for 25A, that's running them at 86% of their rated capacity for the duration of the max-current-draw portion of each run... I bet those suckers get hot during those few seconds...

 

[lolachampcar]

I think it was more of a repeated physical test where he found the amperage that would "pop" the link.

 

[strider]

I have no dog in this fight (other than having a 3 reservation and planning on getting the PxDL version) but I can tell you that this kind of behavior will not stop until Tesla has competition. A MacLaren 12C is not an acceptable replacement for those of us with kids and/or those wanting to remove transmissions from our lives (ALL of them suck). So everyone here needs to hope that Lucid and Faraday become viable. Once people start voting with their wallets Tesla will either fix their behavior or go out of business. If they choose the latter then at least we'll have other options. Until they have competition Tesla has no motivation to change.

 

[Andyw2100]

If you are in Europe for instance and buy a car over the internet based on a 0-60 mph claim of X and a horsepower of Y, it would be reasonable to have expectations of mid and high end performance in line with a car that produces Y hp. When the car shows up with 463/691 or 67% of the expected hp, you might just be a bit disappointed. I would say that would be a reasonable reaction.

@lolachampcar used a person in Europe as his example I'm guessing to drive home the point that that person would not have been able to test drive the car. I'd just like to add that many of us ordering the P85D in the US and Canada before it was actually available were in the exact same situation.

 

[AWDtsla]

Ah very good. I was thinking about these numbers as well.

We know that the 90kW packs still have the same 96s74p cell arrangement (it wasn't until the 100's that they physically stuffed more cells in to the pack). Thus at 1,600A each cell is supplying 21.6A, which is what it's fusible link must deal with.

If wk057's assumption that they are rated for 25A, that's running them at 86% of their rated capacity for the duration of the max-current-draw portion of each run... I bet those suckers get hot during those few seconds...

Yup. It would be a reasonable engineering exercise, that when you're validating your product to operate at this power level, you actually check things like this that are obvious to any random engineer. Wires shouldn't have a cycle life that isn't approaching infinity. They should have never sold the car/pack at that power level.

 

[AWDtsla]

@lolachampcar used a person in Europe as his example I'm guessing to drive home the point that that person would not have been able to test drive the car. I'd just like to add that many of us ordering the P85D in the US and Canada before it was actually available were in the exact same situation.

I don't see how this matters. Tesla games the power levels with the counter, so whenever you go on a test drive you get an unsustainable level of power.

Should feel bad for anyone that bought one of those super-discounted inventory P90D's.. Nearly every moment of that car's driving time was spent with the throttle to the floor.

 

[Andyw2100]

Should feel bad for anyone that bought one of those super-discounted inventory P90D's.. Nearly every moment of that car's driving time was spent with the throttle to the floor.

There's no question that many, MANY Tesla customers have issues to be concerned about.