In an attempt to find the optimum driving speeds between superchargers for the minimum total charge + drive time, I did some number crunching.
Using the Supercharger Table found here Tesla Model S - Supercharger Table for charge times and EVTripPlanner for rated miles used and drive times at different speeds, I plotted the total time for different distances. What did surprise me was that even with shorter distances, there's still an optimum speed below the car's maximum speed.
The data is not very accurate; since the Supercharger Table is rounded to 10 miles and even minutes, and EVTripPlanner is rounded to the nearest minute. Near the optimum, the difference in time with 5mph increments is negligible. I was still able to demonstrate that the charge time curve does indeed overtake the drive time curve. All the curves for different distances look similar, and the optimum drive speed seems to change very near linear with the distance.
It's easy to map routes in EVTripPlanner between superchargers, so I tried to choose superchargers at different distances with little elevation change, near highway ramps, using all the default settings except using the Model S85 with 19" wheels. Since the topic is optimizing time, I decided to assume we just arrived at the first supercharger with 0 miles (presumably from a previous supercharger stop) and are charging just enough to get to the next supercharger at our desired speed with 0 miles left again. I plugged values into the speed multiplier until I got even multiples of 5mph on the highway segment in the "steps" tab, and I used the entire trip drive time.
Here is the longest distance I tried, between FL Port St. Lucie and St. Augustine. It looks like 80mph is the fastest you can drive and make it, and only with a brand new battery. If you have any degradation symptoms (real or "balance" issues), a lower speed will have to be used to avoid the last long minutes of supercharging before departure.
Even at 200 miles, the time difference between 75mph and 80mph is only 10 minutes. That cost 22 rated miles at the top of the battery, which adds about 17 minutes charging time.
Here is a more typical distance, between FL Port Orange and Port St. Lucie:
And another typical distance, between FL Lake City and Ocala:
Here is the shortest distance I tried, between CT Darien N and Milford N:
Disclosure: I did tweak some of the minutes by a few 10ths to smooth out some of the curves, but none more than a half minute.
Using the 85 vs 60 supercharge video Bjorn posted, I compared the charging rate with the Supercharger table and found that the table is a bit optimistic to that video; so even though the table is rather old I can conclude it was constructed with times from a 120kW charger and non-A battery pack. (Maxed at 114kW)
I also tried to make a similar table for the 60kWh battery using that video, but in the video he only charges to 80% so there's not enough data there to do many iterations or very high speeds. Again the resolution is just too low to establish optimum speeds within 5mph, but for the 3 distances I tried (28.8mi, 63.4mi, 80.8 mi) the optimum drive speed seems to be in the range of 80-90mph; slower than in the 85kWh as expected.
The results clearly show that there is no one optimum driving speed for minimum total time.
Using the Supercharger Table found here Tesla Model S - Supercharger Table for charge times and EVTripPlanner for rated miles used and drive times at different speeds, I plotted the total time for different distances. What did surprise me was that even with shorter distances, there's still an optimum speed below the car's maximum speed.
The data is not very accurate; since the Supercharger Table is rounded to 10 miles and even minutes, and EVTripPlanner is rounded to the nearest minute. Near the optimum, the difference in time with 5mph increments is negligible. I was still able to demonstrate that the charge time curve does indeed overtake the drive time curve. All the curves for different distances look similar, and the optimum drive speed seems to change very near linear with the distance.
It's easy to map routes in EVTripPlanner between superchargers, so I tried to choose superchargers at different distances with little elevation change, near highway ramps, using all the default settings except using the Model S85 with 19" wheels. Since the topic is optimizing time, I decided to assume we just arrived at the first supercharger with 0 miles (presumably from a previous supercharger stop) and are charging just enough to get to the next supercharger at our desired speed with 0 miles left again. I plugged values into the speed multiplier until I got even multiples of 5mph on the highway segment in the "steps" tab, and I used the entire trip drive time.
Here is the longest distance I tried, between FL Port St. Lucie and St. Augustine. It looks like 80mph is the fastest you can drive and make it, and only with a brand new battery. If you have any degradation symptoms (real or "balance" issues), a lower speed will have to be used to avoid the last long minutes of supercharging before departure.
Even at 200 miles, the time difference between 75mph and 80mph is only 10 minutes. That cost 22 rated miles at the top of the battery, which adds about 17 minutes charging time.
Here is a more typical distance, between FL Port Orange and Port St. Lucie:
And another typical distance, between FL Lake City and Ocala:
Here is the shortest distance I tried, between CT Darien N and Milford N:
Disclosure: I did tweak some of the minutes by a few 10ths to smooth out some of the curves, but none more than a half minute.
Using the 85 vs 60 supercharge video Bjorn posted, I compared the charging rate with the Supercharger table and found that the table is a bit optimistic to that video; so even though the table is rather old I can conclude it was constructed with times from a 120kW charger and non-A battery pack. (Maxed at 114kW)
I also tried to make a similar table for the 60kWh battery using that video, but in the video he only charges to 80% so there's not enough data there to do many iterations or very high speeds. Again the resolution is just too low to establish optimum speeds within 5mph, but for the 3 distances I tried (28.8mi, 63.4mi, 80.8 mi) the optimum drive speed seems to be in the range of 80-90mph; slower than in the 85kWh as expected.
The results clearly show that there is no one optimum driving speed for minimum total time.