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There is absolutely a good reason for transmissions in an electric vehicle, it's just that most EVs elect to remove them for simplicity instead. I will leave t

There is absolutely a good reason for transmissions in an electric vehicle, it's just that most EVs elect to remove them for simplicity instead. I will leave the interpretation of this graph as an exercise for the reader. https://i.stack.imgur.com/HRUva.gif https://i.stack.imgur.com/HRUva.gif

hinkley 4y ago
I predict we'll end up with AWD vehicles with two motors. The front wheels will have a motor tuned for the low end, the rear wheels a motor that is tuned for higher speeds, and the controllers will adjust how much power goes front or rear depending on the need for torque, traction and mph. Right now AWD EVs seem to get slightly lower range, and I would expect that to eventually to even out or reverse, even with the weight of extra equipment.
- sib 4y ago
  Some (not all) non-performance AWD Teslas do exactly this. As early as 2014, when they intro'd the S 85D, the front and rear motors were set up so one would be more used at low speeds, for better acceleration, and one at high speeds, for more efficient cruising.
- kwhitefoot 4y ago
  This is how my Model S 70D is setup. The front motor is a somewhat smaller than the rear.
ilyt 4y ago
Most EVs don't use permanent magnet motors. Try again. The curve you linked is seriously misleading. Like just look at any EV dyno curve, it is not "torque starts at top and immediately starts falling" Transmission means extra losses and extra weight tho. It's not just "free" increase in efficiency. It does make sense but in typical city/reasonable highway speed it's just not worth it
- idiotsecant 4y ago
  That is a strangely aggressive response - I'm not claiming every single ev is pmac but many are. What sort of motor do you think a Tesla model 3 uses, for example? Even considering that, induction motors also have an efficiency curve which is the point I'm making. If you care about efficiency motors have a sweet spot. Sometimes you care a lot about that, sometimes not.
  - ilyt 4y ago
    > What sort of motor do you think a Tesla model 3 uses, for example? IPM-SynRM https://www.youtube.com/watch?v=esUb7Zy5Oio https://www.youtube.com/watch?v=esUb7Zy5Oio They went into a lot of effort to optimize it over RPM range. If you want to make a point use real motor curves at least. Your graph suggests it goes to sub 20% efficiencies at low speed which is completely false and would suggests way higher gains from gearbox than in reality. Hell, it would suggest ICE like performance, it's THAT bad.

hinkley 4y ago

I predict we'll end up with AWD vehicles with two motors. The front wheels will have a motor tuned for the low end, the rear wheels a motor that is tuned for higher speeds, and the controllers will adjust how much power goes front or rear depending on the need for torque, traction and mph. Right now AWD EVs seem to get slightly lower range, and I would expect that to eventually to even out or reverse, even with the weight of extra equipment.

sib 4y ago
Some (not all) non-performance AWD Teslas do exactly this. As early as 2014, when they intro'd the S 85D, the front and rear motors were set up so one would be more used at low speeds, for better acceleration, and one at high speeds, for more efficient cruising.
kwhitefoot 4y ago
This is how my Model S 70D is setup. The front motor is a somewhat smaller than the rear.

ilyt 4y ago

Most EVs don't use permanent magnet motors. Try again. The curve you linked is seriously misleading. Like just look at any EV dyno curve, it is not "torque starts at top and immediately starts falling" Transmission means extra losses and extra weight tho. It's not just "free" increase in efficiency. It does make sense but in typical city/reasonable highway speed it's just not worth it

idiotsecant 4y ago
That is a strangely aggressive response - I'm not claiming every single ev is pmac but many are. What sort of motor do you think a Tesla model 3 uses, for example? Even considering that, induction motors also have an efficiency curve which is the point I'm making. If you care about efficiency motors have a sweet spot. Sometimes you care a lot about that, sometimes not.
- ilyt 4y ago
  > What sort of motor do you think a Tesla model 3 uses, for example? IPM-SynRM https://www.youtube.com/watch?v=esUb7Zy5Oio https://www.youtube.com/watch?v=esUb7Zy5Oio They went into a lot of effort to optimize it over RPM range. If you want to make a point use real motor curves at least. Your graph suggests it goes to sub 20% efficiencies at low speed which is completely false and would suggests way higher gains from gearbox than in reality. Hell, it would suggest ICE like performance, it's THAT bad.