Hi. After the recent EPA documents, we have more data to compare. I've calculated that the Model 3 drivetrain is 5.7% more efficient than the Model S. With the Model 3, they are now pretty close to the limits of what's possible in terms of efficiency.

The EPA documents have two numbers we can use: road load horsepower numbers from coastdown tests and dyno range numbers. Here is a table that shows what type of energy loss each number includes. I have used information from this Tesla blog post to create this table.

We have these two numbers for the Model 3 80 (aka Model 3 LR):

Road Load HP @ 50mph = 9.95 HP (Source: Page 16)

Highway dyno score = 454.64 miles (Source: Page 7)

9.95 HP means, this is the amount of power you need to apply for the car to continue going at 50 mph. During the coastdown test, the car is in neutral. Therefore drivetrain losses (motor, inverter, gearbox, motor controller and high power wire losses) are not included. During the dyno test, air drag is included because they have entered that into the dyno settings. To do that, they do the coastdown test, take some readings, convert that to a mathematical curve represented by a formula that looks like AV+BV^2+CV^3 and then they enter the A, B, C coefficients to the dyno. In other words, the dyno is able to compensate for air drag and rolling resistance at any speed for that particular vehicle.

We can find out the drivetrain losses by subtracting road load numbers from dyno test numbers. The problem is, the road load and dyno test numbers are in different units. One is horsepower and the other is miles. To solve this issue, I've came up with two methods. I don't know which is more accurate but both have similar results. The first shows 5.7% difference. The second shows 5.8%.

9.95 HP is 7.42 kW. We also know from the EPA dyno document that the Model 3 80 has 78.27 kWh usable capacity. Therefore if we continued to apply power for the car to coast at 50 mph until the total energy consumption is 78.27 kWh, we would have to continue doing that for 78.27 kWh / 7.42 kW = 10.55 hours. The coastdown HP number is at 50 mph. Therefore, the range would be 10.55 hours * 50 miles/hours= 527.45 miles.

In other words, imagine the Model 3 is in neutral and some other force is pushing the car so it continues to coast at 50 mph. Also, imagine this other force happens to have the exact same energy as the Model 3 80 battery which is 78.27 kWh. In this scenario, the car would go 527.45 miles.

However, instead of some other force pushing the car, if the car drives using its own motor, then it would drive for 454.64 miles. Therefore, 1- 454.64/527.45= 13.80% energy is lost in the motor, inverter, power electronics and wires. This might seem like a lot but it is actually pretty good because these components are in series. For example, if the inverter is 95% efficient, then 100 units energy is reduced to 95 units. If the motor is 94% efficient, now you need to take 94% of 95 units which is 0.95*0.94= 89%. Using this method, the numbers look like this:

In this table, the Model S 60 and 75 require the same power to overcome the road load because they are the same car. This is the software limited 60.

Looking at these numbers, I've noticed two interesting details:

1. The Model 3 80 drivetrain is 5.7% more efficient than the Model S 75.

2. The Model S 75D is 2.2% more efficient than the Model S 75.

Model 3 highway dyno score was 454.64 miles (source: page 7). The average speed for that test is 48.4 mph. See the test details tab here. Therefore, the duration of that test should be 454.64 miles / 48.4 miles/hours= 9.39 hours.

We also know that the road load is 9.95 HP (7.42 kW). Pushing the car for 9.39 hours at 50 mph would consume 9.39 hours * 7.42 kW= 69.70 kWh. However, when the car drives itself it consumes the entire 78.27 kWh which means drivetrain losses are 78.27 kWh - 69.70 kWh= 8.57 kWh. That's 8.57/78.27= 10.95% of consumption. The whole table for this method looks like this:

The result is similar to the previous method. The Model 3 80 drivetrain appears to be 5.8% more efficient than Model S 75.

Another interesting detail is that when the Model S switches to the Model 3 technology, the real world range of the Model S 75D should increase from 235 miles to 235*1.057= 248 miles.

The EPA documents have two numbers we can use: road load horsepower numbers from coastdown tests and dyno range numbers. Here is a table that shows what type of energy loss each number includes. I have used information from this Tesla blog post to create this table.

We have these two numbers for the Model 3 80 (aka Model 3 LR):

Road Load HP @ 50mph = 9.95 HP (Source: Page 16)

Highway dyno score = 454.64 miles (Source: Page 7)

9.95 HP means, this is the amount of power you need to apply for the car to continue going at 50 mph. During the coastdown test, the car is in neutral. Therefore drivetrain losses (motor, inverter, gearbox, motor controller and high power wire losses) are not included. During the dyno test, air drag is included because they have entered that into the dyno settings. To do that, they do the coastdown test, take some readings, convert that to a mathematical curve represented by a formula that looks like AV+BV^2+CV^3 and then they enter the A, B, C coefficients to the dyno. In other words, the dyno is able to compensate for air drag and rolling resistance at any speed for that particular vehicle.

We can find out the drivetrain losses by subtracting road load numbers from dyno test numbers. The problem is, the road load and dyno test numbers are in different units. One is horsepower and the other is miles. To solve this issue, I've came up with two methods. I don't know which is more accurate but both have similar results. The first shows 5.7% difference. The second shows 5.8%.

**Method 1:**Calculating miles from road load horsepower.9.95 HP is 7.42 kW. We also know from the EPA dyno document that the Model 3 80 has 78.27 kWh usable capacity. Therefore if we continued to apply power for the car to coast at 50 mph until the total energy consumption is 78.27 kWh, we would have to continue doing that for 78.27 kWh / 7.42 kW = 10.55 hours. The coastdown HP number is at 50 mph. Therefore, the range would be 10.55 hours * 50 miles/hours= 527.45 miles.

In other words, imagine the Model 3 is in neutral and some other force is pushing the car so it continues to coast at 50 mph. Also, imagine this other force happens to have the exact same energy as the Model 3 80 battery which is 78.27 kWh. In this scenario, the car would go 527.45 miles.

However, instead of some other force pushing the car, if the car drives using its own motor, then it would drive for 454.64 miles. Therefore, 1- 454.64/527.45= 13.80% energy is lost in the motor, inverter, power electronics and wires. This might seem like a lot but it is actually pretty good because these components are in series. For example, if the inverter is 95% efficient, then 100 units energy is reduced to 95 units. If the motor is 94% efficient, now you need to take 94% of 95 units which is 0.95*0.94= 89%. Using this method, the numbers look like this:

In this table, the Model S 60 and 75 require the same power to overcome the road load because they are the same car. This is the software limited 60.

Looking at these numbers, I've noticed two interesting details:

1. The Model 3 80 drivetrain is 5.7% more efficient than the Model S 75.

2. The Model S 75D is 2.2% more efficient than the Model S 75.

**Method 2:**Converting road load and dyno range to kWh:Model 3 highway dyno score was 454.64 miles (source: page 7). The average speed for that test is 48.4 mph. See the test details tab here. Therefore, the duration of that test should be 454.64 miles / 48.4 miles/hours= 9.39 hours.

We also know that the road load is 9.95 HP (7.42 kW). Pushing the car for 9.39 hours at 50 mph would consume 9.39 hours * 7.42 kW= 69.70 kWh. However, when the car drives itself it consumes the entire 78.27 kWh which means drivetrain losses are 78.27 kWh - 69.70 kWh= 8.57 kWh. That's 8.57/78.27= 10.95% of consumption. The whole table for this method looks like this:

The result is similar to the previous method. The Model 3 80 drivetrain appears to be 5.8% more efficient than Model S 75.

Another interesting detail is that when the Model S switches to the Model 3 technology, the real world range of the Model S 75D should increase from 235 miles to 235*1.057= 248 miles.

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