I'm looking for a math wiz smarter than I am to help with what is probably a simple formula.
Example:
I have a 6 hour 360 mile trip. I will have to stop once to charge at a super charger.
If I drive half the trip at 60 mph for 3 hours rather rather than 55 mph I arrive at the charger 15 minutes early. Is it possible that the time saved by more speed could use up enough extra battery power that I would have to charge for an extra 5, 10, or 15 minutes thus lessening or negating the time I saved by driving faster?
Any math wiz's willing to take a whack at this?
Thanks.
The problem is, you need to know just how much of a difference in battery SoC you'll have left driving at 60 vs 55 mph and what speed you'll be able to charge at the supercharger. And those numbers have HUGE variances.
For myself, I drive the same 4 mile stretch of highway everyday to and from work (close to 80 mph average). And I always get a message saying if I drove less that 70 mph, I could save 0.2%. Let's stretch this and make it worse at 0.4%, so that it's 0.1% per mile.
So, if we mix in your numbers and drive at 80 mph over the course of 180 miles (60 mph for 3 hours), it would use an additional 18% (180 x 0.1) and get there in 2.25 hours... a supercharger won't take 0.75 hrs (or 45 minutes) to charge just 18% (to cover the difference). If we use the slowest 50kW speed and converting the 18% to about 14.4 kW (assuming 80-ish kW battery pack), it would take it a little over 17 minutes, leaving you ahead by 28 minutes to now charge up the rest of the battery pack (about 55% or so to cover 180 miles used). Actually, if you charge to 75% (from 0%), it would take about 1.5 hrs and get you to your destination (with about 3% remaining), meaning you would be halfway through your charge time by the time a person going 60 mph ENTERS.
Stepping back a bit, using a 50kW charger allows you to charge 12.5 kW in 15 minutes. And 12.5 kW is almost 16% of the MY's battery. Then tack on the assumption, there's no way you would use 16% more of the battery going 60 mph instead of 55 mph over the 180 miles, you'll be ahead going 60 mph.
I think for most drivers, faster speed outweighs the extra % used.
At least, right up until you get pulled over and a ticket.