5 ms·

So, I'll just hop in here and lay out the spoiler. There is a major performance difference in the Taycan, it's endurance, and it's highly likely this transmiss

by ztjio 7y ago

So, I'll just hop in here and lay out the spoiler. There is a major performance difference in the Taycan, it's endurance, and it's highly likely this transmission is a key element to achieving it. For those that don't know, Tesla's cars can not keep their maximum performance up for a very long time. The battery gets hot and lowers power output until it cools back down. The Taycan, while not having as impressive max specs or range (and some serious questionability about the charging claims) CAN keep its maximum performance indefinitely. At least through a full discharge of the battery pack, but, also after a recharge it can keep going and they demonstrated this recently with a 24 hour marathon test drive stopping only to charge it. So, without really getting into all the weird perception based arguments, there is clearly a difference in performance and the transmission may be critical to it.

solotronics 7y ago
Another reason the Taycan can output near maximum power for a much extended time period is it operates at 800v vs 650v as compared to the Tesla.
- eigenloss 7y ago
  Higher voltage alone does not magically give you longer sustained maximum power.
  - adrianN 7y ago
    It's also unclear to me why a gearbox alone would give you longer sustained maximum power.
    - elihu 7y ago
      Most electric motors are most efficient and can generate the most power within a certain RPM range. (It's a lot wider than gas engines, but beyond a certain speed the torque falls off.) If you can drive at high speeds at a more efficient motor RPM, then that's less excess heat for the motor and inverter to deal with, and less current draw from the batteries.
      - kenhwang 7y ago
        Electric motors are pretty much opposite of gasoline engines. Motors have peak torque at 0-2krpm and it drops off rapidly after that. Gasoline cars tend to hit peak torque near the end of their rpm range (ignoring turbos that can change that in any number of ways). From what I can see, most electric motors are tuned to have peak efficiency at ~5krpm which is conveniently around freeway driving speeds.
        eigenloss 7y ago
        One might even imagine they were engineered to be optimally efficient at freeway driving speeds! :D
    - URSpider94 7y ago
      For single-speed EV’s, the motors are operating very far away from their maximum efficiency point at high speeds. By upshifting, you can reduce the number of revs required at top speed, which should improve efficiency and reduce heating of the motors.
    - ztjio 7y ago
      Alone it's probably not enough. In combination with other design decisions, it could be the key though. Take for example the smaller battery. Normally that would be a big limiting factor as battery size is somewhat indicative of maximum power output. But by shifting gears once through the acceleration curve, they can compensate for the lower max power. Furthermore, they could keep higher speeds with less constant power output. The reason this matters is because a smaller battery will produce less heat overall, which will be easier to cool, and so on. Anyway it's just a theory. The facts remain: the Taycan can do something the Teslas can't and this gearbox is the biggest single meaningful difference in design of the powertrain. It stands to reason they are related facts to some degree or another.
      - deleted 7y ago
        [deleted]
  - coribuci 7y ago
    Higher voltage means less current for the same power. Since the power dissipated on the battery is proportional with the current you want to draw less current. What a lot of people do not understand is that the lack of a gearbox in an electric car is a big problem. When the motor is running suboptimally the excess energy taken from the battery will be transformed in heat.
    - mcot2 7y ago
      It depends what speeds make the motor run sub-optimally for a particular vehicle. The range 0-80 MPH is sufficient for almost all normal driving. If you want to make an efficient track car that can operate at high speeds optimally by all means introduce a gearbox. Its going to add more weight, complexity and maintenance though. I don’t think thats the target for any of Tesla’s cars besides the 2020 roadster though.
zaroth 7y ago
This is more of a function of battery chemistry on the S/X - the Model 3 does not have the same power restriction under load.
- reitzensteinm 7y ago
  Which makes Elon's promise of sending the Model S round the ring a bit confusing. Presumably it would be a suicide run to match the Taycan, which to my understanding would involve modifications and not be eligible for the same category. Either it was an idle boast, or we're about to see the launch of the 21700 Model S.
  - jm1234567890 7y ago
    The new raven model S has the same battery chemistry as model 3
    - simonsquiff 7y ago
      It does not. Raven altered the motor and suspension, battery is same as it ever was for MS (18650) M3 uses 27100, which is taller so can’t just be dropped into the current MS
      - mcot2 7y ago
        Not 100% accurate. It is a new battery pack but still based on the 18650 cells. Tesla battery packs have a numerical code which was incremented for the packs in the raven models. The most pronounced new feature is the ability to charge at up to 200kW on the new V3 superchargers. M3 can do up to 250kW and non-raven S/X can only do in the low 100s.
  - ztjio 7y ago
    Once around the ring is not an issue. It's a day at the track that's a problem, not one lap. And not an issue at all if you're fine with waiting periodically while the battery temp comes back to optimal.

by ztjio 7y ago

solotronics 7y ago

Another reason the Taycan can output near maximum power for a much extended time period is it operates at 800v vs 650v as compared to the Tesla.

eigenloss 7y ago
Higher voltage alone does not magically give you longer sustained maximum power.
- adrianN 7y ago
  It's also unclear to me why a gearbox alone would give you longer sustained maximum power.
  - elihu 7y ago
    Most electric motors are most efficient and can generate the most power within a certain RPM range. (It's a lot wider than gas engines, but beyond a certain speed the torque falls off.) If you can drive at high speeds at a more efficient motor RPM, then that's less excess heat for the motor and inverter to deal with, and less current draw from the batteries.
    - kenhwang 7y ago
      Electric motors are pretty much opposite of gasoline engines. Motors have peak torque at 0-2krpm and it drops off rapidly after that. Gasoline cars tend to hit peak torque near the end of their rpm range (ignoring turbos that can change that in any number of ways). From what I can see, most electric motors are tuned to have peak efficiency at ~5krpm which is conveniently around freeway driving speeds.
      - eigenloss 7y ago
        One might even imagine they were engineered to be optimally efficient at freeway driving speeds! :D
  - URSpider94 7y ago
    For single-speed EV’s, the motors are operating very far away from their maximum efficiency point at high speeds. By upshifting, you can reduce the number of revs required at top speed, which should improve efficiency and reduce heating of the motors.
  - ztjio 7y ago
    Alone it's probably not enough. In combination with other design decisions, it could be the key though. Take for example the smaller battery. Normally that would be a big limiting factor as battery size is somewhat indicative of maximum power output. But by shifting gears once through the acceleration curve, they can compensate for the lower max power. Furthermore, they could keep higher speeds with less constant power output. The reason this matters is because a smaller battery will produce less heat overall, which will be easier to cool, and so on. Anyway it's just a theory. The facts remain: the Taycan can do something the Teslas can't and this gearbox is the biggest single meaningful difference in design of the powertrain. It stands to reason they are related facts to some degree or another.
    - deleted 7y ago
      [deleted]
- coribuci 7y ago
  Higher voltage means less current for the same power. Since the power dissipated on the battery is proportional with the current you want to draw less current. What a lot of people do not understand is that the lack of a gearbox in an electric car is a big problem. When the motor is running suboptimally the excess energy taken from the battery will be transformed in heat.
  - mcot2 7y ago
    It depends what speeds make the motor run sub-optimally for a particular vehicle. The range 0-80 MPH is sufficient for almost all normal driving. If you want to make an efficient track car that can operate at high speeds optimally by all means introduce a gearbox. Its going to add more weight, complexity and maintenance though. I don’t think thats the target for any of Tesla’s cars besides the 2020 roadster though.

zaroth 7y ago

This is more of a function of battery chemistry on the S/X - the Model 3 does not have the same power restriction under load.

reitzensteinm 7y ago
Which makes Elon's promise of sending the Model S round the ring a bit confusing. Presumably it would be a suicide run to match the Taycan, which to my understanding would involve modifications and not be eligible for the same category. Either it was an idle boast, or we're about to see the launch of the 21700 Model S.
- jm1234567890 7y ago
  The new raven model S has the same battery chemistry as model 3
  - simonsquiff 7y ago
    It does not. Raven altered the motor and suspension, battery is same as it ever was for MS (18650) M3 uses 27100, which is taller so can’t just be dropped into the current MS
    - mcot2 7y ago
      Not 100% accurate. It is a new battery pack but still based on the 18650 cells. Tesla battery packs have a numerical code which was incremented for the packs in the raven models. The most pronounced new feature is the ability to charge at up to 200kW on the new V3 superchargers. M3 can do up to 250kW and non-raven S/X can only do in the low 100s.
- ztjio 7y ago
  Once around the ring is not an issue. It's a day at the track that's a problem, not one lap. And not an issue at all if you're fine with waiting periodically while the battery temp comes back to optimal.