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P85D Power draw numbers do not add up...

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The car could easily log current vs time and model the cooling of the fuse. Maybe protecting the fuse is one of the things that causes a Tesla MS to go into "wimp" mode on the track...


That's an interesting thought.

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Most car enthusiasts agree, 0-60 times are a worthless indicator of a cars performance because of so many variables. Its a marketing gimmick that caters to non-enthusiasts as a standard benchmark number.

How anyone can call a car the 'fastest-anything-in-the-world' based off of 0-60 times is just plain stupid, sorry. Sure, its quick out of the hole- but thats it- it is not fast over 100MPH, it tops out at 155MPH (the Hellcat can reach 200MPH+), its 1/4 mile time is equal to most 500-550HP ICE sports sedans, and it most certainly cannot run a quick lap time around a track comparable to most any sports sedan out there from BMW M, AMG, Porsche, etc. Remind me again how the P85D is "the fastest production sedan in the world" when the only metric being used is 0-60 times???


Number of times I have used my car's hole shot capability to my advantage in city driving? Every day.
Number of times I have needed to go faster than 155 mph? Zero.

0-60 is a datapoint, nothing more, but for the kind of driving that I use my Tesla for, it is far more relevant than top speed. Actually, a street start (5-60) is even more relevant for me, since that tends to eliminate clutch dumping and launch control. That's a number that I am sure the P85D will simply dominate compared to nearly anything else on the road.
 
Number of times I have used my car's hole shot capability to my advantage in city driving? Every day.
Number of times I have needed to go faster than 155 mph? Zero.

0-60 is a datapoint, nothing more, but for the kind of driving that I use my Tesla for, it is far more relevant than top speed. Actually, a street start (5-60) is even more relevant for me, since that tends to eliminate clutch dumping and launch control. That's a number that I am sure the P85D will simply dominate compared to nearly anything else on the road.

Indeed. And I'll add:

The number of times I've needed to accelerate flat-out for 1/4 mile: Zero
Number of times I've needed it for several hundred yards: innumerable.
 
Is this 691 bhp figure mentioned anywhere else than the Design Studio? I find it weird that neither Elon or the blog mentions this number, which would kind of be something to brag about. I'm leaning towards marketing tactic! I desperately hope I am wrong.

I think Elon mentioned it in the unveiling event. And the number sounds about right for what it would take to get a car that heavy to go 0-60 in 3.2 seconds.
 
Oh that's a good data point hidden between the lines.

So at a nominal pack voltage of 346 you were pulling ~925 Amps or 4.2C during that 7 seconds at top speed.

Based upon that power consumption an S85 could run at top speed for about ~16 minutes, full pack to empty.

Given that 1C is the discharge rate for 1 hour, then anything over 4C would have to be less than 1/4th of an our, correct?

A 4.2 discharge would imply draining the battery in about 14 minutes or so...

Not that 2 minutes makes that much of a difference. :)
 
Based upon that power consumption an S85 could run at top speed for about ~16 minutes, full pack to empty.

which is about the same amount of time the Veyron can run at top speed, before running out of fuel.

of course it's top speed is higher (267MPH), but you'll probably need a new set of $25K tires and the $70K tire mounting service in France after that run as well :)

Bugatti Veyron @ Top Speed
 
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Could this be the root of power limiting after a few spirited laps on the track? Is the car going into limp mode to keep this fuse from overheating and blowing?

The car could easily log current vs time and model the cooling of the fuse. Maybe protecting the fuse is one of the things that causes a Tesla MS to go into "wimp" mode on the track...

That's an interesting thought.

I know, right? :)

The battery is liquid cooled. The fuse is not. It would be a bad idea to connect a thermally activated fuse to a heat sink.

I think we may have found our track fun limiting component. Still waiting to hear whether several miles of track driving would be enough to approach thermal thresholds for that fuse.
 
Go around the track a bit then look at the front passanger corner of the pack with a FLIR? The top cover for the fuse might be visible from somewhere near the frunk...

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To support these kinds of currents, you probably need more like a 1" diameter copper rod...

All of the current in the pack runs through a 2/0 gauge copper wire down the center... which is not 1" diameter. They just seem to have calculated the thermal limits of the components to work well under normal conditions.
 
One solution to getting both the 0-60 acceleration and the improved range is to use a different gearing for the front and rear motors. A shorter gear at the rear will improve acceleration just like Saleen has done. At cruising speed a taller front gearing should be able to lead to a higher top speed and a better efficiency as well. Since the motors are independently controlled the different gearing should not be a problem
 
Ah, yeah - I see it. Hmmm, it's sealed in a plastic housing (orange) with a plastic cover (black). That's going to make getting on IR read on the fuse itself impossible. Dangit.

Ah yeah, a direct reading would be impossible without removing that cover... although it is pretty close to the cover, so it wouldn't surprise me if that entire area of the pack heated over time.
 
Ah yeah, a direct reading would be impossible without removing that cover... although it is pretty close to the cover, so it wouldn't surprise me if that entire area of the pack heated over time.

If the housing and cover were metal, yeah we could get a decent indirect read through the radiated and conducted heat. But not so with plastic. It's a poor heat conductor.
 
Also, the Hellcat will run a 10.8 second 1/4 mile with drag radials and 11.2 on street tires. The P85D claims a 11.8 1/4 mile time. How can Tesla claim "fastest production sedan in the world" when clearly the Hellcat beat them to the punch? Sounds like Tesla's marketing team needs to be sat down and talked to.

Not so fast there Perfect,
I am somewhat of a fan of the Hellcat. However, that Hellcat will, in no way, run in the 10's without a drag strip launch "pad" (usually concrete) sprayed down with Moose Juice on the factory equipped tires. I am looking forward to this real-world street drag race. It just might be closer than you think.