-
Welcome to CayenneEVforum! If you're joining us from Taycanforum, then you may already have an account here.
If you were registered on Taycanforum as of August 27, 2025 or earlier, then you can simply login here with the same username and password
If you wish, you can remove your account here.
OP
OP
whan
Well-Known Member
- First Name
- Will
- Joined
- Nov 5, 2021
- Threads
- 5
- Messages
- 196
- Reaction score
- 34
- Location
- Marin Co, CA
- Vehicles
- Taycan RWD, Ferrari 458, Lexus GX460
- Thread starter
- #17
I think the answer is that it depends - the PBP has a greater voltage (610-835V) than the PB (520-720V). Assuming the same components in the rest of the car that have the same current draw peak, the system alone should be able to handle a proportionally greater power in both output and charging (Electrical Power = Voltage * Current). We know that the system is indeed designed to have the same current draw with both batteries, as the increase in battery pack energy of 79.2kwh to 93.4kwh is identical to the change in voltage on a % basis. Energy = Power*Time, and because Power = Voltage*Current, the increase in pack energy is fully attributed to the voltage increase.
Motor torque is proportional to the AC Voltage/Frequency ratio (this determines magnetic field strength, or flux, which impacts torque) inputted into the motor. Motor speed is proportional to AC supply frequency. Modern VFDs (Variable Frequency Drives, otherwise known as inverters as they also convert the DC from the battery to AC) can modulate the voltage and frequency being inputted into a motor independently. However, motors are rated for a certain Voltage/Frequency ratio that they can handle. In theory, any higher and you have overflux, having too strong of a magnetic field that it can cause motor failure due to heat buildup and other physics stuff.
There is a maximum motor speed that can be achieved while maintaining the rated V/F ratio, for a given maximum Voltage able to be supplied. Beyond this point, because the system no longer has any more voltage to give, spinning the motor any faster results in a reduction of torque (frequency continues to rise, voltage stays constant, V/F ratio decreases and thus decreases torque). Prior to reaching maximum voltage, the V/F ratio can be maintained, as the system can just keep adding voltage with increasing frequency, and thus max torque can be achieved at any point before this. This is why we see the dyno curves for EVs, where max torque is generated at 0RPM until a certain RPM, and then falls off after that. Horsepower curves on the other hand increase linearly until the same certain RPM and then are relatively flat (slowly declining due to other losses)
Because the PBP has more available voltage, this explains why its peak horsepower number is higher. It can maintain the V/F ratio (max torque) at a higher frequency, and thus higher motor rpm (Power = torque * rpm). This is also confirmed by the peak HP difference between the PB and PBP, the PBP peak voltage is 16% more than the PB, and the PBP rated peak HP of 469 is about 16% more than the PB rate peak HP of 402.
Going back to peak torque though, even though a motor has a rated V/F ratio, it is in theory possible to provide a higher V/F ratio and "overflux" the motor to generate additional torque above the rated V/F torque, particularly prior to the frequency at which peak voltage is achieved under the rated V/F ratio. The PBP has more voltage that it actually could provide vs the PB, and in this case it's possible it could provide more peak torque in an overflux scenario. But I think the magnitude of overflux probably is largely limited by motor design and rating - Porsche probably doesn't want to provide more torque in the PBP as they're worried about motor durability, as opposed to anything related to battery voltage
TLDR: Torque is probably capped in both PBP and PB because Porsche is worried about motor reliability
Motor torque is proportional to the AC Voltage/Frequency ratio (this determines magnetic field strength, or flux, which impacts torque) inputted into the motor. Motor speed is proportional to AC supply frequency. Modern VFDs (Variable Frequency Drives, otherwise known as inverters as they also convert the DC from the battery to AC) can modulate the voltage and frequency being inputted into a motor independently. However, motors are rated for a certain Voltage/Frequency ratio that they can handle. In theory, any higher and you have overflux, having too strong of a magnetic field that it can cause motor failure due to heat buildup and other physics stuff.
There is a maximum motor speed that can be achieved while maintaining the rated V/F ratio, for a given maximum Voltage able to be supplied. Beyond this point, because the system no longer has any more voltage to give, spinning the motor any faster results in a reduction of torque (frequency continues to rise, voltage stays constant, V/F ratio decreases and thus decreases torque). Prior to reaching maximum voltage, the V/F ratio can be maintained, as the system can just keep adding voltage with increasing frequency, and thus max torque can be achieved at any point before this. This is why we see the dyno curves for EVs, where max torque is generated at 0RPM until a certain RPM, and then falls off after that. Horsepower curves on the other hand increase linearly until the same certain RPM and then are relatively flat (slowly declining due to other losses)
Because the PBP has more available voltage, this explains why its peak horsepower number is higher. It can maintain the V/F ratio (max torque) at a higher frequency, and thus higher motor rpm (Power = torque * rpm). This is also confirmed by the peak HP difference between the PB and PBP, the PBP peak voltage is 16% more than the PB, and the PBP rated peak HP of 469 is about 16% more than the PB rate peak HP of 402.
Going back to peak torque though, even though a motor has a rated V/F ratio, it is in theory possible to provide a higher V/F ratio and "overflux" the motor to generate additional torque above the rated V/F torque, particularly prior to the frequency at which peak voltage is achieved under the rated V/F ratio. The PBP has more voltage that it actually could provide vs the PB, and in this case it's possible it could provide more peak torque in an overflux scenario. But I think the magnitude of overflux probably is largely limited by motor design and rating - Porsche probably doesn't want to provide more torque in the PBP as they're worried about motor durability, as opposed to anything related to battery voltage
TLDR: Torque is probably capped in both PBP and PB because Porsche is worried about motor reliability
Last edited:
