Dual Motor Range

[Waiting4M3]

I know most everyone expected the dual motor AWD models to have longer range, as is the case with MS, due to higher efficiency, assuming that Tesla will use the same battery packs for AWD vs RWD models. But why is Tesla showing the same 220-310 mile range for the AWD models? Typo? Or placeholder to be changed later? Or will Tesla shrink the battery pack size for AWD models to take advantage of the higher efficiency of dual motor and still end up with the same range?

 

[kev1n]

probably a place holder but id assume it would be just a bit higher

 

[Skione65]

I know most everyone expected the dual motor AWD models to have longer range, as is the case with MS, due to higher efficiency, assuming that Tesla will use the same battery packs for AWD vs RWD models. But why is Tesla showing the same 220-310 mile range for the AWD models? Typo? Or placeholder to be changed later? Or will Tesla shrink the battery pack size for AWD models to take advantage of the higher efficiency of dual motor and still end up with the same range?

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@Waiting4M3,

It is my understanding that by the time AWD goes into production by Spring/Summer '18 you'll be able to configure with 'either' the Long Range Battery at 310 range OR the Standard Battery at 220. They are giving you the choice....whereas currently only the LRB is offered in a RWD config to expedite/simplify production 'RampUp'.

Ski

 

[R.S]

I know most everyone expected the dual motor AWD models to have longer range, as is the case with MS, due to higher efficiency, assuming that Tesla will use the same battery packs for AWD vs RWD models. But why is Tesla showing the same 220-310 mile range for the AWD models? Typo? Or placeholder to be changed later? Or will Tesla shrink the battery pack size for AWD models to take advantage of the higher efficiency of dual motor and still end up with the same range?

View attachment 242258

Probably a place holder and a bit higher range for the AWD cars. But I think the difference might be smaller, than on the S.

The S AWD motors are newer and more advanced than the RWD motor on the S, which has an additional effect on efficiency, besides the AWD efficiency boost.

 

[JeffK]

The AWD version is going to be awesome. They don't want to give away too much now because they don't want to affect S sales or RWD Model 3 sales.

 

[Waiting4M3]

@Waiting4M3,

It is my understanding that by the time AWD goes into production by Spring/Summer '18 you'll be able to configure with 'either' the Long Range Battery at 310 range OR the Standard Battery at 220. They are giving you the choice....whereas currently only the LRB is offered in a RWD config to expedite/simplify production 'RampUp'.

Ski

I think you misunderstood my point. In the MS the AWD has longer range than RWD model, with the same battery pack size, because dual motor is more efficient. But why would the AWD base M3 have the same 220 mile range as the RWD base M3? and also why would the AWD long range M3 have the same 310 mile range as the RWD long range M3?

 

[Waiting4M3]

Probably a place holder and a bit higher range for the AWD cars. But I think the difference might be smaller, than on the S.

The S AWD motors are newer and more advanced than the RWD motor on the S, which has an additional effect on efficiency, besides the AWD efficiency boost.

Thanks for the reminder about the motor difference. M3 supposedly has PM motors so that's another wrinkle. I wonder if PM motor has more or less uniform efficiency across the full range of speed, which would in turn reduce or increase the need to use dual motor to optimize efficiency at two different speeds.

 

[siggyfreud]

It's possible they haven't EPA tested the dual motor versions yet. It's also possible they will simply software-limit it to 310 miles so it remains consistent with their RWD line, so the choice is really about what traction version you need. Hard to say what their strategy is at this point.

 

[gregincal]

Thanks for the reminder about the motor difference. M3 supposedly has PM motors so that's another wrinkle. I wonder if PM motor has more or less uniform efficiency across the full range of speed, which would in turn reduce or increase the need to use dual motor to optimize efficiency at two different speeds.

I read that permanent magnet motors aren't able to spin freely without charge (torque idle) the way that induction motors do, so if they are using PMAC motors they can't use that trick.

 

[R.S]

I read that permanent magnet motors aren't able to spin freely without charge (torque idle) the way that induction motors do, so if they are using PMAC motors they can't use that trick.

Yea, that's at least partially true. At lower speeds it doesn't really need to be a problem, but at higher speeds there are considerable demagnetizing losses in the stator iron, even if turned off.

They could do an induction motor, PM-motor combo, but usually induction motors are more efficient at high speeds, so not sure how Tesla will handle this.

 

[R.S]

The AWD version is going to be awesome. They don't want to give away too much now because they don't want to affect S sales or RWD Model 3 sales.

I hope you won't complain, if the AWD Model 3 doesn't match your hopes for awesomeness.

 

[JeffK]

I hope you won't complain, if the AWD Model 3 doesn't match your hopes for awesomeness.

I have no doubts that Tesla will overdeliver.

 

[Knightshade]

The AWD version is going to be awesome. They don't want to give away too much now because they don't want to affect S sales or RWD Model 3 sales.

This would make more sense if not for the fact Tesla has preorders for so many RWD cars already they won't need any new buyers until LONG after the AWD specs are published.

Given the S75 and S75D had almost no difference in range or performance (like 9 miles range and 0.1 0-60) it seems unlikely it'd make much difference in the M3 either

 

[JeffK]

This would make more sense if not for the fact Tesla has preorders for so many RWD cars already they won't need any new buyers until LONG after the AWD specs are published.

And you know this how?

 

[commasign]

The motor used in the Model 3 is already high efficiency. Adding another motor just increases weight. There may be a slight efficiency gain from being able to switch between front and rear wheel drive which might offset the weight increase. That would explain why the delivery estimate page claims the same 220 and 310 mile range. But do not count on any significant increase in range like there is on the S single vs dual motor.

 

[McRat]

Yea, that's at least partially true. At lower speeds it doesn't really need to be a problem, but at higher speeds there are considerable demagnetizing losses in the stator iron, even if turned off.

They could do an induction motor, PM-motor combo, but usually induction motors are more efficient at high speeds, so not sure how Tesla will handle this.

Question:

Say I need 30 kW to sustain 75 mph. If I run one motor at 20kW and the other at 10kW, what is the downside? Less current is being used, so lower resistance gain from heat.

 

[Thomas Edison]

They could do an induction motor, PM-motor combo, but usually induction motors are more efficient at high speeds, so not sure how Tesla will handle this.

This is what I'm really hoping for.

 

[Thomas Edison]

Question:

Say I need 30 kW to sustain 75 mph. If I run one motor at 20kW and the other at 10kW, what is the downside? Less current is being used, so lower resistance gain from heat.

I would think that if you are highway cruising that only the more officiant motor would be powering the car.

 

[McRat]

I would think that if you are highway cruising that only the more officiant motor would be powering the car.

No, without a total thrust of 30kW, you'd slow down. AWD car use torque division all the time. Sport will bias more rear torque, touring a little less, and rain/winter, 50/50.

 

[Thomas Edison]

No, without a total thrust of 30kW, you'd slow down. AWD car use torque division all the time. Sport will bias more rear torque, touring a little less, and rain/winter, 50/50.

Why can't it use only one motor if it's let's say 10% more efficient? We are just talking about highway cruising. I don't get it, if it needs more torque to accelerate it then does the 50/50 or what ever it needs.