So with Elon Repeatedly saying how adding a second motor improves efficiency...

[v12 to 12v]

I'm fairly sure the S85 got 300 miles on the old Tesla "55mph test". 265 miles is EPA and much closer to reality. This new "65mph test" is different again and so not really comparable. There used to be a range calculator somewhere on the TM site, I don't know but you could probably specify 65mph and see what it spits out.

Charlie -

You were correct. The original range stated for the Model S was 300 miles and based on 55 mph. The rated range was reduced to 265 miles when the EPA made a wholesale change to a 5-cycle test that had more variables.

 

[Tasdevil]

Once the gigafactory starts producing batteries and they cost a "conservative 30% less" then there's no argument. Maybe there's no argument at the moment or maybe tesla is just structuring their pricing knowing that batteries are what will reduce in price the most in the near future.

 

[mknox]

Just noticed this on the Canadian order page:

S85 = 460 km range (at 100 km/h)
S85D = 475 km range (at 100 km/h)

P85 = 460 km range (at 100 km/h)
P85D = 440 km range (at 100 km/h)

What the heck? The standard model gets better range with dual motors but the P suffers with reduced range.

 

[Bighorn]

Just noticed this on the Canadian order page:

S85 = 460 km range (at 100 km/h)
S85D = 475 km range (at 100 km/h)

P85 = 460 km range (at 100 km/h)
P85D = 440 km range (at 100 km/h)

What the heck? The standard model gets better range with dual motors but the P suffers with reduced range.

There's a big HP boost on the P85D while the S85D stays the same.

 

[nwdiver]

Just noticed this on the Canadian order page:

S85 = 460 km range (at 100 km/h)
S85D = 475 km range (at 100 km/h)

P85 = 460 km range (at 100 km/h)
P85D = 440 km range (at 100 km/h)

What the heck? The standard model gets better range with dual motors but the P suffers with reduced range.

The S85D was designed for efficiency while the P85D was designed for performance. Elon seemed to hint that achieving his target of 0-60 in 3.2s was a challenge so it looks like they made some compromises. IMO there is a >50% chance that Tesla will be an AWD only car company by the time the 3 is released... AWD was initially going to be an option in the X and now its slated to be standard.

 

[ZsoZso]

If 2 motors give better efficiency than 1, why not go all the way to 4 motors, separate one for each wheel ? They could all be smaller of course, giving the same total power output, but allowing even finer tuning and optimization to improve cornering where the inner and outer wheels need to turn with slightly different speeds.

 

[mknox]

The S85D was designed for efficiency while the P85D was designed for performance. Elon seemed to hint that achieving his target of 0-60 in 3.2s was a challenge so it looks like they made some compromises. IMO there is a >50% chance that Tesla will be an AWD only car company by the time the 3 is released... AWD was initially going to be an option in the X and now its slated to be standard.

Yes, but I thought Elon stated that the AWD cars were supposed to be all things including more efficient. Perhaps he was only referring to the non-P versions.

- - - Updated - - -

There's a big HP boost on the P85D while the S85D stays the same.

There was a HP difference on the original S vs. P too, but supposedly if you drove them similarly, you got the same efficiency.

 

[Bighorn]

There was a HP difference on the original S vs. P too, but supposedly if you drove them similarly, you got the same efficiency.

The S and P have basically the same motor, but the inverter could allow a higher current to flow to the P, so the operator determining the output could drive them similarly with equivalent efficiency. The new Performance D has the same motor of the S/P plus another 221 HP motor up front that the driver can no longer can modulate in like manner. Time and testing will tell whether the dual motors of the P85D are more efficient in some circumstances and less in others than its predecessors.

 

[GregA]

The new Performance D has the same motor of the S/P plus another 221 HP motor up front that the driver can no longer can modulate in like manner. Time and testing will tell whether the dual motors of the P85D are more efficient in some circumstances and less in others than its predecessors.

(Edit: oops, I see what you were saying now.)

The single motor 60 & 85 have a 380hp motor, the p85 has a 470hp motor.

The dual motor 60 & 85 have 2x 188hp (376hp total) while the p85 has a 221hp front and 470hp rear (691hp total).

It will be interesting to see real world effect on range with the gearing differences, driving differences, and braking changes.

 

[Jeff N]

Here's a weak example: Toyota's hybrid Highlander is only available in AWD using a 2nd electric motor (similar in concept to Tesla's dual motor AWD). Toyota started with a FWD hybrid, then offered both, and then dropped the FWD version because it got slightly worse EPA estimates.

 

[green1]

If 2 motors give better efficiency than 1, why not go all the way to 4 motors, separate one for each wheel ? They could all be smaller of course, giving the same total power output, but allowing even finer tuning and optimization to improve cornering where the inner and outer wheels need to turn with slightly different speeds.

Diminishing returns. You might scrape a tiny bit more efficiency out of it, but it would likely be dwarfed by the extra weight added, and nobody would be willing to pay enough to do it.

 

[Sunlight]

Just thinking aloud - if the reason dual motors give greater efficiency is due to the different gearing and power delivery, maybe there is a case for using dual motors on the rear wheels. One in front of the axle and one behind with different crown wheels/gearing and software to optimize the power delivered by each motor - both utilized for max acceleration.

OK I know this keeps RWD and not AWD but it would give two motors (with back-up in the event of the failure of one motor!) with the perfect spread of torque/power/gearing at much reduced costs - one diff; one set of driveshafts and UJs; one alternator (?).... Just generally more compact.

With the cost midway between single motor RWD and dual motor AWD, it may be a good option. Thoughts?

 

[Red Sage]

Just thinking aloud - if the reason dual motors give greater efficiency is due to the different gearing and power delivery, maybe there is a case for using dual motors on the rear wheels. ... With the cost midway between single motor RWD and dual motor AWD, it may be a good option. Thoughts?

The Fisker Karma used two rear electric motors and it was slower than any variant of the Tesla Model S. The Mercedes-Benz SLS AMG Electric Drive uses two rear motors, two front motors, and is slower than the Tesla Model S P85D. Both those cars are far less efficient than any variant of the Tesla Model S, so the Fisker Karma has an electric range of perhaps 22 miles, and the Mercedes-Benz SLS AMG Electric Drive might manage 125 miles of range. There does not appear to be any particular performance or efficiency benefit of multiple motors at each axle, beyond the mechanical torque steer that it allows while cornering.

 

[wallet.dat]

The Fisker Karma used two rear electric motors and it was slower than any variant of the Tesla Model S. The Mercedes-Benz SLS AMG Electric Drive uses two rear motors, two front motors, and is slower than the Tesla Model S P85D. Both those cars are far less efficient than any variant of the Tesla Model S, so the Fisker Karma has an electric range of perhaps 22 miles, and the Mercedes-Benz SLS AMG Electric Drive might manage 125 miles of range. There does not appear to be any particular performance or efficiency benefit of multiple motors at each axle, beyond the mechanical torque steer that it allows while cornering.

I think you may have misunderstood his post since you're citing cars that have nothing to do with the Model S other than they run on electricity and have four tires. But to address your concerns, there may in fact be an argument for individual motors per wheel. When building for a certain hp target, using individual motors allows you to use motors which are smaller in diameter, thus reducing the overall CoG even further, and that is always a good thing. While this may not be a huge deal on a sedan like the S, in a more sporting platform (future Roadster perhaps) this would prove to be a huge advantage. I'd love to see a quad motor Roadster with a CoG approaching that of a Formula 1 car.

 

[Tasdevil]

The Fisker Karma used two rear electric motors and it was slower than any variant of the Tesla Model S. The Mercedes-Benz SLS AMG Electric Drive uses two rear motors, two front motors, and is slower than the Tesla Model S P85D. Both those cars are far less efficient than any variant of the Tesla Model S, so the Fisker Karma has an electric range of perhaps 22 miles, and the Mercedes-Benz SLS AMG Electric Drive might manage 125 miles of range. There does not appear to be any particular performance or efficiency benefit of multiple motors at each axle, beyond the mechanical torque steer that it allows while cornering.

I'll think you'll find that the reason why they are slower is because of power constraints from the smaller battery pack.

You should probably be comparing the AWD S to the Rimac. In order to do a "fair/closer" comparison of 2 motor vs 4 motor.

 

[MartinAustin]

does anyone think this may be something they use to get the Model 3 to 200+ mile range?

Not me. Their goal is to replace all the world's oil-driven cars with electric cars. Having the price as low as possible will bring in the largest number of customers. They will keep AWD as an option, but the base model won't have it. At least with the Model 3, it will be a very compelling option. The reason AWD isn't a no-brainer on all cars already is because the oil-driven AWD solution costs you at the pump every time you drive... in addition to the initial surcharge. The Tesla car actually goes further, so it could be said that if you get the AWD option, you get your money back at some future point.

I did some calculations that indicated that a 40kWh battery could push the Model 3 for 200 miles, assuming it uses 250Wh/mile, and that's without the benefit of AWD.

if they really want to sell 500,000 cars a year; it really needs AWD

Don't agree... plenty of 2WD cars sell way more than that. I know dozens of friends who say categorically they are going to get a Model 3... that car is going to sell like hotcakes and I bet Tesla will continue with a waiting list for some time.

FYI Subaru's cheapest car in 2014 is the $17,800 Impreza, so the 2017 2WD Model 3 will be around twice the price. It should be simple economics to say Impreza could outsell the Model 3, based upon Subaru's manufacturing capacity and price. Even if the Model 3 is more desirable (Interesting side note - averaging 30.5mpg, the Impreza is using 1,115Wh mile ) Things will be different once Tesla has an even cheaper car.

 

[wallet.dat]

Not me. Their goal is to replace all the world's oil-driven cars with electric cars.

EVs will replace ICEVs in the same way TV replaced radio. Or how Email replaced snail mail. That is, I don't believe they'll completely replace ICEVs, but they will offer a lot more options to the consumer. Plus there will always be purists and connoisseurs who prefer the old school; whether that be shaving with a safety razor & badger hair brush, or manually shifting a transmission on a gasoline engine car.

 

[Red Sage]

I did some calculations that indicated that a 40kWh battery could push the Model 3 for 200 miles, assuming it uses 250Wh/mile, and that's without the benefit of AWD.

Most people report between 280 Wh and 320 Wh per mile as their general usage of the Tesla Model S. The EPA uses 380 Wh per mile as their determined parameter. I'm not certain how, but apparently they count the total amount of power that leaves the wall when filling, as opposed to the amount of energy stored in the battery pack itself.

Oh, and 40,000 divided by 250 comes to 160... That's still 40 miles short of 200 miles. It would have to be 200 Wh/mile (or better) to go 200 miles with a 40 kWh battery pack.

My calculations say that a vehicle with a 40 kWh battery pack would have to weigh around 2,800 lbs to approach 200 miles at highway speeds or on the EPA 5-cycle tests. That means the car would have to be about the same size as a two-seater such as the third generation Mazda RX-7. I'd certainly love to see a car like that, but I doubt it will be part of the initial Model ☰ platform. FYI... The Fiat 500e is practically microscopic, and still weighs in at 2,952 lbs and only has a 24 kWh battery pack.

Besides, that would basically be 40% smaller in mass than the Tesla Model S. Elon Musk has said the Model ☰ would be about 20% smaller instead, which works out to roughly 3,700 lbs. Considering that the Tesla Model S 40 had an EPA rated range of 140 miles, that means a Model ☰ 40 would maybe manage a range of 168 miles from them -- if you were lucky. You would have to hypermile on a flat windless plain to crawl over 200 miles in a 40 kWh version of the car, and I don't think that is what Tesla Motors is shooting for at all.

At 50 kWh it certainly becomes 'doable'... The problem is that it is only barely so, maybe 210~212 miles or so. If the EPA again reports a finding only 90% of what Tesla Motors gets in their own tests, then the range would fail to meet the 200+ mile goal at around ~190 miles instead. I believe that Elon would prefer to shatter the goal, rather than fall short of it for a 'moral victory'.

So a 60 kWh battery pack is really the absolute bare minimum that can be used on a vehicle as substantial as the Model ☰ is expected to be. That should be able to achieve ~250 miles of range. And if the EPA [FOULS] Tesla Motors again, it would still be at least 225 miles.

 

[lude33]

hi everyone, first post on this forum

About efficiency with 2 engine. The first reason seems to be that with 2 smallers engines you can use only one engine at low speed/load to be in the good range where efficiency is in 80/90%. A bigger engine when at low rpm/load have a bad efficiency under 50%. So modulation on 2 small engine allow to be always in the good range...

(Sorry for my english from a french man)

 

[Vitaman]

Merci....very good first post and perfectly understandable.
Welcome!