How is current to the motor limited? Electronically or physically?

[apacheguy]

It's certainly possible, but the current delivered in the 30+mph range is about twice as much(according to the dash gauge) as the initial burst. Once you drive the car, you can definately see what I'm talking about. The question is, how much software limiting is happening?

I believe there is a fundamental difference in the hardware. As Zextraterrestrial mentioned regarding his factory tour, the performance version utilizes a unique power train. This is supported by the REST API in which you can query your car and not only see if it is perf/non-perf, but also determine if it has the performance power train. These two separate variables suggest there is more to the perf version than simply lifting a software limitation.

Also, I'm sure Tesla would be offering "anytime" upgrades to non-perf owners just as they are for 60 kw users that did not initially purchase SC.

 

[teslasguy]

Maybe it's just my car? I dunno. The performance model at the Get Amped event had a very violent takeoff. Not so with my car. My car does however have very good acceleration once you get going.

I know for a fact that my car (P85) has changed substantially in regards to traction control since I got it in Mid-Dec.
It used to actually chirp the tires some and hop the rear end a bit even with traction control on.
Now I can't get the tires to spin at all even with traction control turned off. Only time I can get any spin at all is if launching from a good size puddle of water.
I brought this up to my Service Manager and he confirmed that this is normal now and he thinks they changed it through a firmware update.
So, I guess now if you want to do any kind of burnout or tire warmup at the track you have to pull the fuse.

 

[Zextraterrestrial]

I know for a fact that my car (P85) has changed substantially in regards to traction control since I got it in Mid-Dec.
It used to actually chirp the tires some and hop the rear end a bit even with traction control on.
Now I can't get the tires to spin at all even with traction control turned off. Only time I can get any spin at all is if launching from a good size puddle of water.
I brought this up to my Service Manager and he confirmed that this is normal now and he thinks they changed it through a firmware update.
So, I guess now if you want to do any kind of burnout or tire warmup at the track you have to pull the fuse.

mine is opposite!

I can spin past 35 mph now w/ a hoppy skitter.
on the unprepared drag strip I was spinning past 65 mph and needed to ease on the throttle to get better than a 4.8 0-60

I tried a warm up burnout once but it didn't help. But w/ TC off I had no problem spinning the tires quick in the water!

 

[scaesare]

So it sounds like folks have seen physically different drivetrain components, and the API can detect the difference as well (assuming it's really keying off hardware, and not just an identifier in the firmware somewhere).That certainly supports the premise that there's certainly going to be physical constraints to higher performance other than just software...

 

[JRP3]

It's certainly possible, but the current delivered in the 30+mph range is about twice as much(according to the dash gauge) as the initial burst.

I assume the car displays battery current, that will be lower than motor current initially until the motor reaches a certain speed.

 

[qwk]

It actually displays XXXkw which is the power the battery is delivering atm. For example, if you are parked, but turn on the heat, it displays ~6kw.

 

[jerry33]

And unfortunatly, any tuning would likely require an illegal hack of Tesla's software.

Unless Tesla provides an API.

 

[JRP3]

Thinking about this a bit, if you were able to get into the software and raise current limits, one way to possibly avoid melting anything would be to tap into the motor/inverter cooling system and pre cool that fluid with an external source, and at the same time tap into the battery coolant system and heat that. A warm pack and cold motor/inverter should allow you to get more out of the system, at least for a single pass drag run.

 

[Sticky]

There are also physical limitations of the motor. Increase current too much and you start melting the windings. Performance then drops to zero.

The current I'm talking about is current they already intended to run themselves.

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And unfortunatly, any tuning would likely require an illegal hack of Tesla's software.

I wouldn't say illegal it's your car you can modify the software. It happens on hundreds of thousands of cars today plenty of ECU tuners out there.

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I don't believe a Model S is going to be as easily tunable as an internal combustion engine car, especially with all of the proprietary stuff going on. There is far more complicated and less tangible stuff going on here than in a gas car. We might see tuners with PhDs in electrical engineering and computer science...but it will probably be rare, if we see it at all.

Just my guess.

It's not going to be easy but there is untapped potential here and that is part of the appeal.

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Undoubtedly the software tune has to be different for the P85 car... but if the software commands the system to ramp up to power levels the inverter (or other components) can't deliver, then it obviously won't work.

Given that is is apparently cheaper to build 60KWH battery packs and software-limit them to 40KWH output, I wonder if it's also more economical to build only one flavor of inverter, and simply software limit it's output.

Of course, it was stipulated that only 4% of battery packs would have been 40's... whereas there appear to be a significantly greater percentage of P-models out there... so engineering, building, and supporting two different configurations there may make more sense...

I was under the impression the P85 has a different inverter.

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I know for a fact that my car (P85) has changed substantially in regards to traction control since I got it in Mid-Dec.
It used to actually chirp the tires some and hop the rear end a bit even with traction control on.
Now I can't get the tires to spin at all even with traction control turned off. Only time I can get any spin at all is if launching from a good size puddle of water.
I brought this up to my Service Manager and he confirmed that this is normal now and he thinks they changed it through a firmware update.
So, I guess now if you want to do any kind of burnout or tire warmup at the track you have to pull the fuse.

Interesting. Wondering if pulling the fuse would allow a better launch if one had some dedicated drag rubber?

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So it sounds like folks have seen physically different drivetrain components, and the API can detect the difference as well (assuming it's really keying off hardware, and not just an identifier in the firmware somewhere).That certainly supports the premise that there's certainly going to be physical constraints to higher performance other than just software...

I'm somewhat surprised there is so little info in this respect. Tesla does not seem to be saying much.