Cool! I wonder if the "1.2" second claim by Tesla is just rounding down the number.
By the way, are you able to achieve 10.8 second quarter mile just like the TRC channel car? And what 's your 0-60 amd 0-100 mph time? thanks!
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New P100DL makes xxx HP at the battery!
- Thread starter scottm
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- Driving Dynamics Model S
By the way, are you able to achieve 10.8 second quarter mile just like the TRC channel car? And what 's your 0-60 amd 0-100 mph time? thanks!
Don't have the 1/4 and 100 mph times. 0-60 without roll out is 2.79 secs. Roll out should decrease the 0-60 time by about 0.25 secs.
It doesn't say 1.20 secs. It wouldn't be unusual to quote anything less than 1.300 as 1.2.
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Is that 0-60 mph time from vbox?
That's nice. 2.79 - 0.25 = 2.54 seconds for 0-60 mph. That's almost as fast as P100DL.
The motors are rated for a combined 691 in the P85D and a combined 763 on the P90D(even though they're the same motors). Tesla specs 532 hp at the motor shaft for a 458KW at the battery power which would be about a 13% conversion loss from battery terminal to motor shafts so we're not even close to being motor limited(which is what I think you meant to say)?
At any rate, I predict 1760 to 1765 amps * (310 to 314) volts.
I thought fiksegts said tesla is reporting the shaft horsepower of the p100d as 603hp. It could be that the current pyro-fuse or inconel contactor is limited to 1600 amps and a latter upgrade will allow higher amps.
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St Charles
Tesla, not TSLA!
My guess is that the Amperage does not change but the voltage sag is reduced due to the addition of 18650 Cells and lower internal pack resistance. I would be surprised if the max output was above 550kW
Let's see if that adds up. The P90DL V1 and P85DL were claimed by Tesla to be 532 hp. Max power at about 458KW and vbox power at wheels 480 so the 532 seems reasonable 13% loss from battery to shaft and 10% loss from shaft to wheels. Only thing we know for sure is at 458KW (614 hp at battery) to wheels (480 hp) is about 22% total.
Now enter P90DL V2, or is it V3? ....which is making 511KW. That's 685 hp at the battery. I haven't seen a vbox power chart of a V2 yet(if someone sends me a vbo file, I'll generate the chart) but if we have the same percentage drivetrain loss:
614 -> 532
685 -> 593
So 593 shaft power for a 512KW P90DL.
There's no way that the P100DL is only going going to be 603. But I wouldn't fault Tesla for understating true power. I would fault them for overstating it....as many others did with the original P85D.
If they had to keep the current at 1600 amps for some reason, the difference between 593 hp and 603 corresponds to a difference of about 5 or 6 volts in sag, which goes along with St Charles' speculation of just less sag.
One big problem might be, that we only scale in current, not in voltage.
You can't just "feed" an electric motor current and voltage and hope that it turns it to power. Its always voltage that draws current and the voltage needed depends on the speed the motor spins.
Simplified, the current makes the torque, while the voltage makes the maximum speed, where the torque can be applied. Speed times torque is power (torque times revelations per second times 2 pi).
Now both have their limit, current and voltage, current for example because of heat buildup in the windings. So if our motors just can handle 1584 Amps, but 400V. Going up to 1760 A at 360V won't get us to to the same 633.6kW input power.
The same goes for the inverters. They might be able to handle 600V, but not 1700A.
So even if we could get 550kW into the motors and 550kW out of the battery, we might not be able to match those two.
Now Tesla could increase the packs voltage, but I am not so sure if supercharging might be possible anymore and the cars internal charger would have to be built for it(which seems likely, if they planned to increase voltage).
In conclusion, I sure hope that output power has increased the same percentage as energy has, but it isn't as simple as my first post had made it seem to be.
You can't just "feed" an electric motor current and voltage and hope that it turns it to power. Its always voltage that draws current and the voltage needed depends on the speed the motor spins.
Simplified, the current makes the torque, while the voltage makes the maximum speed, where the torque can be applied. Speed times torque is power (torque times revelations per second times 2 pi).
Now both have their limit, current and voltage, current for example because of heat buildup in the windings. So if our motors just can handle 1584 Amps, but 400V. Going up to 1760 A at 360V won't get us to to the same 633.6kW input power.
The same goes for the inverters. They might be able to handle 600V, but not 1700A.
So even if we could get 550kW into the motors and 550kW out of the battery, we might not be able to match those two.
Now Tesla could increase the packs voltage, but I am not so sure if supercharging might be possible anymore and the cars internal charger would have to be built for it(which seems likely, if they planned to increase voltage).
In conclusion, I sure hope that output power has increased the same percentage as energy has, but it isn't as simple as my first post had made it seem to be.
I'm pretty sure the inverter will take care of stepping up or down the voltage/current as needed. The battery is not fed directly into the motor.
I can step down 240 volts at 15 amps down to 120 volts at 30 amps (same power either weay). Sure there's a small efficiency cost but we really don't know what's being fed to the actual motor inputs.
The inverter works with PWM, so it can modulate sine functions with less voltage, but not with more voltage. For that you need a step up transformer, which I don't necessarily think the Model S has.
You don't necessarily need a transformer:
The NHW20 model Toyota Prius HEV uses a 500 V motor. Without a boost converter, the Prius would need nearly 417 cells to power the motor. However, a Prius actually uses only 168 cells and boosts the battery voltage from 202 V to 500 V.
Boost converter - Wikipedia, the free encyclopedia
A boost converter, or step up converter, is the same as a transformer, just for DC-DC uses. But I looked at the Tesla specs and the motor is rated at 320V, so it should be able to handle more current, since the power could be higher, than it is today.
According to what I can find looking at the BMS, the current limit in 100 packs is 1750A. It's about 1500A for a Ludicrous 85 and early 90, and 1600A for the newer 90's. The older non-ludicrous 85's were 1300A.
They are not at all the same thing. One is a passive device for converting alternating current, the other is an active device for directly converting a lower dc voltage to a higher one at less current. With a transformer they would first have to convert the battery dc voltage to ac, pass it through the transformer, then rectify the ac back to dc. The transformer and associated electronics would be heavier and less efficient. A boost converter doesn't even have to use inductance. It can use capacitors to increase the voltage. The end result might be the same, but the means are quit different.
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