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New battery for D vehicles?
- Thread starter ACDriveMotor
- Start date
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- Model S
breser
AutoPilot Nostradamus
Elon said at the event that the AWD system is just more efficient. I'd imagine it's probably due to the differences in sizing of the motors/gearing that allows them to get more out of the AWD setup.
I believe it was mentioned that there were efficiency gains (I'm assuming first in the drivetrain itself, and then having the additional motor, likely geared for a certain speed)
Gizmotoy
Active Member
Exactly. IMO, the big top speed bump basically confirms the front motor is geared taller. As speed increases, more and more power will be delivered by the front motor (many active-differential AWD systems do this already because pulling the car is more stable than pushing at high speeds). Since it's geared taller, you'll see improved efficiency at highway speeds.
techiesjc
Member
Right on Giz! That front motor is like an "overdrive" gear on an ICE transmission. The front motor is half the HP as the rear and with a taller gear the front motor "pulls" the car along on the freeway at your constant speed. This and backing off the 470 HP motor will reduce you draw on the battery for sure. It also has a nice balance for regen with the tall gear on the front 221 HP motor you get a nice scale of regen at freeway speeds when decelerating. An impressive design!
Am I the only one who realizes that:
#1: Tesla has been known to fib on range increases before (See P85+ claims)
#2: The EPA range on a 85 (non-D) is 265. The figures Tesla is quoting are not EPA for the "D" models. Not an Apples to Apples comparison.
I certainly understand the claims about the gearing difference, but I also will take any claims made by Tesla/Elon with a grain of salt based on their past history of not delivering some of their promised hype or playing with the numbers and facts.
Still Love the car and the company, but not going to automatically assume this info is factual.
Everyone should know enough about the EPA 5-cycle test to simulate the results. Remember that the EPA changed the test right around the time the S was coming out, so the Tesla engineers were estimating using apples only to have the EPA switch to oranges.
Besides, with cars geared for high-end speed, the EPA number isn't going to be accurate anyway. You will likely be driving the car faster than 55 mph so the wind resistance and different gearing will have an impact.
Not always bad either. One car I had had an estimated EPA highway of 25 mpg. If I drove it at 65-68 instead of 55, I got almost 30 mpg. Turns out the engine ran much more efficiently at ~2K rpm instead of 1500 rpm.
If I cruised at 70-75, the mpg dropped back to the EPA number
.
Bottom line, your mileage will vary but not because of Tesla - because your driving patterns have a huge impact on range and the efficiency curves of the D cars are unknown (to us) at this point. You could get lucky and have the curves fit right into your favorite speeds. Or not. We'll just have to see.
Besides, with cars geared for high-end speed, the EPA number isn't going to be accurate anyway. You will likely be driving the car faster than 55 mph so the wind resistance and different gearing will have an impact.
Not always bad either. One car I had had an estimated EPA highway of 25 mpg. If I drove it at 65-68 instead of 55, I got almost 30 mpg. Turns out the engine ran much more efficiently at ~2K rpm instead of 1500 rpm.
If I cruised at 70-75, the mpg dropped back to the EPA number
.Bottom line, your mileage will vary but not because of Tesla - because your driving patterns have a huge impact on range and the efficiency curves of the D cars are unknown (to us) at this point. You could get lucky and have the curves fit right into your favorite speeds. Or not. We'll just have to see.
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Everyone should know enough about the EPA 5-cycle test to simulate the results. Remember that the EPA changed the test right around the time the S was coming out, so the Tesla engineers were estimating using apples only to have the EPA switch to oranges.
Besides, with cars geared for high-end speed, the EPA number isn't going to be accurate anyway. You will likely be driving the car faster than 55 mph so the wind resistance and different gearing will have an impact.
Not always bad either. One car I had had an estimated EPA highway of 25 mpg. If I drove it at 65-68 instead of 55, I got almost 30 mpg. Turns out the engine ran much more efficiently at ~2K rpm instead of 1500 rpm.
If I cruised at 70-75, the mpg dropped back to the EPA number
Bottom line, your mileage will vary but not because of Tesla - because your driving patterns have a huge impact on range and the efficiency curves of the D cars are unknown (to us) at this point. You could get lucky and have the curves fit right into your favorite speeds. Or not. We'll just have to see.
We won't know for 6 months until enough people have them to report meaningful discharge rates. I assume they are still basing it on 300/mi so we will know soon enough.
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