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green1
Active Member
amzng_ev
Member
The S85D has two smaller motors, which are more efficient. It would still have more range if it was on 21s.
The S85D has better range because its AWD system uses two smaller motors while the P85D uses the standard, larger P85 rear motor and a smaller motor for the front. So the S85D's drivetrain weighs less than the P85D's drivetrain (less weight == more range) and the overhead losses of the smaller motor are less than that of the larger motor.
green1
Active Member
The range quoted is not EPA. I suspect part of what they are doing is compensating for the tires in this quoted range.
EPA requires tire sizes to be correct on model variations for testing when certain criteria are met. Obviously, P85+ was never tested (or reported) separately from S85 because they do not have exactly the same range (whether that is relevant is another issue).
With this announcement, Tesla is giving all sorts of varying ranges which is over and above what the EPA would require.
And then there is the motor size.
The actual EPA variations on range will be smaller since city driving will likely be slightly worsened in certain circumstance with AWD - more weight. Also at slower speeds, rolling resistance matters more so tire variations matter more. The P85D looks the best on the highway but may have the worst low speed range of any 85 kwh S (who cares of course since you don't usually need tons of range in the city).
EPA requires tire sizes to be correct on model variations for testing when certain criteria are met. Obviously, P85+ was never tested (or reported) separately from S85 because they do not have exactly the same range (whether that is relevant is another issue).
With this announcement, Tesla is giving all sorts of varying ranges which is over and above what the EPA would require.
And then there is the motor size.
The actual EPA variations on range will be smaller since city driving will likely be slightly worsened in certain circumstance with AWD - more weight. Also at slower speeds, rolling resistance matters more so tire variations matter more. The P85D looks the best on the highway but may have the worst low speed range of any 85 kwh S (who cares of course since you don't usually need tons of range in the city).
Wonder what Tesla could do with 4 smaller engines regarding range. S85Q with 350 miles range and even better acceleration and top speed? Replace battery to lighter battery with same energy and we might see a S85Q with 400 miles range and yet better acceleration because of less total weight?
Larger battery capacity will take longer time to charge and might lead to queues at the SC. Longer range is possible without increasing battery capacity and is preferable in my opinion.
Larger battery capacity will take longer time to charge and might lead to queues at the SC. Longer range is possible without increasing battery capacity and is preferable in my opinion.
deonb
Active Member
Exactly the opposite. Batteries charge much quicker at the bottom half of the curve, so larger batteries will reduce the queue size.
Today, if you need 250 miles of range at a SuperCharger, you'll be there for 75 minutes.
If there was hypothetically a 170kw/H battery, and you need 250 miles of range, you'll be there for 45 minutes.
Now of course, if you wanted 500 miles of range at a SuperCharger on a 170kW/h battery, you'll be there for 120 minutes. But then you'd have 500 miles of range, and can skip the next 2 SuperChargers.
Bighorn
Top Supercharger
I asked my sales rep why there was only a modest improvement in performance in S85D vs S85, meaning why didn't they just keep the standard rear motor and add the front one like they did for P85D. He said that it was a conscious compromise between performance and range. So, slight performance upgrade in S85 and increased range rather than one or the other.
It doesn't though. It simply specifies how much power the motor is specified to deliver, not what it's ultimately capable of.
I question if there really is going to be a rear drive unit engineering change or if this is going to be electronically limited, similar to the way a 40 was limited via software.
Bighorn
Top Supercharger
They have a new small motor that generates ~188 HP. Are you suggesting that by coincidence they are electronically throttling back a 380 HP motor to 188? Highly unlikely and cost inefficient.
Fair point, but my engineer's sixth sense tells me it's got to be a smaller motor in back. They have to have a different drive train up front, just for space considerations (though it's also true that no one's seen the new frunk space in the D versions); at that point it makes perfect sense to use it in the back, too, which is where a good chunk of the increased range would come from. If the S85D and P85D shared all drivetrain mechanical components and the only difference was inverter electronics and/or software (as in the current 2WD lineup), the x85D's would both be capable of the same range.
Yes, I stand corrected but my assumption was to fully load the battery. That would take longer time but as you say, then you could skip a SC. However, less battery weight would mean less energy consumption and therefor less charging. With more efficient battery, you could choose either less weight, more energy storage or a combination.
ToddRLockwood
Active Member
This question has been posed by many people since the D introduction. I imagine that it has to do with the gross weight and size of 4 motors vs. 2 motors that deliver the same overall performance. In-wheel motors have never been considered a viable option because of the added unsprung weight added to each wheel. The lighter the wheel load, the better as far as handling is concerned.
I'm simply challenging out that the assertion of what they ARE doing being made in some posts based on what the ordering page says.
Tesla has chosen to quote what power the motor would deliver, not what it's capable of, therefore using that as an authoritative source of what the motor size must be is questionable.
We have at least two instances of a component being specifically upgraded solely based on matching the car configuration: inverter (for the P models), and 60 & 85kWh battery packs.
We also have several instances of Tesla including hardware on the car capable of more, but limited based on the configuration: 40kWh packs, supercharging hardware, motor (in the non-P), autopilot sensor package.
Obviously time will tell, but until then it's speculation, and thus stating authoritatively one way or the other is difficult.
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