Based on your own numbers and Electrify America's current 31 cent per kWh pricing, it saves 30 minutes going 75 mph over 65 mph, and it only costs $6.51 more. Basically, it's a question of how much your time is worth. Also, based on your numbers and starting with a full charge at the national average electricity rates: At 65 mph, it will cost less to make the trip in a Bolt EV than it would to take a 50 mpg gas car with $3.00 per gallon gas prices, so "expensive" is relative.
The difference between 75 and 60mph is 41kwh. About $12. It is a lunch for me. I can't turn 30 min into anything when I am on a leisure road trip.
And the average U.S. fleet fuel economy is about half of a 50 mpg car...
www.epa.gov
I would hope that anyone driving a Bolt would only be considering a hatchback hybrid as an alternative. However, since joining this forum several years ago, I have learned that people buy this car for all sorts of reasons unrelated to efficiency, or CO2. We are a fascinating species.And the average U.S. fleet fuel economy is about half of a 50 mpg car...
Agency Releases Annual Automotive Trends Report Showing Marginal Increases in Fuel Economy | US EPA
EPA News Release: Agency Releases Annual Automotive Trends Report Showing Marginal Increases in Fuel Economy
120 kWh at 31 cents per kWh is $37, but that's assuming you're leaving with an empty battery. Home charging should cost less than $10 for a full battery, which represents nearly half of that total, so it's less than $30 for the entire trip. Sure, you can compare to equivalent size gas cars, most of which get around 35 to 40 mpg when driven at freeway speeds. You can do the rest of the math from there.
While that's true, most hatchbacks with the Bolt EV's equivalent cargo capacity would get maybe 40 mpg at freeway speeds, and that's the high end. The average would be closer to 35 mpg.
Then your numbers don't work. 33 kWh + 120 kWh to travel 500 miles at 65 mph would mean an efficiency of less than 3.3 mi/kWh, which would be more accurate for 70 to 75 mph driving. With an average driving speed of ~70 mph, my typical consumption is about 145 kWh for a 500-mile trip. An average driving speed of 65 mph would be significantly more efficient. 120 kWh would probably be overly optimistic, but 153 kWh is completely unrealistic. Also, leaving home with 55% battery is unrealistic. It might make sense if you have no access to charging at home, but even then, you'd still want to leave with at least 70% battery.
To make that work, you're assuming that you're starting at 0%. Most Bolt EV owners will start with at least 50 kWh of energy "in the tank." So a 500-mile trip at 65 mph (I think ABRP's collected data had the Bolt EV's efficiency at 65 mph at 3.87 mi/kWh) would require charging 70 kWh (your numbers: 120 kWh minus 50 kWh) or 79 kWh (ABRP's numbers: 129 kWh minus 50 kWh) at public DCFC in order to complete the trip. At Electrify America's current 31 cents per kWh, that's $21.70 (your numbers) to $24.49 (ABRP's numbers). Again, that's assuming you're leaving with 80% to 90% battery, which would represent less than 60 kWh including losses ($7.96 at the national average electricity rate of 13.26 cents per kWh).
You're still not addressing why you need to leave with just over half a battery. Just so a majority of the charging is done at a higher cost? Anyway, yes, that would increase cost and time.
I built a spreadsheet to calculate the ideal speed assuming chargers could be located exactly where needed. You need to assume full charge from home because that's more likely. Somewhere around 75 MPH is the sweet spot, though generic guidance isn't so useful for actual trip planning since there is no such thing as chargers exactly where you need them.
Why? Why would you ever leave on a trip with such a low SoC, especially when you know you will be paying more for juice along the way?
Not only that, the specifics of the chargers and fueling infrastructure changes. Perhaps someone is in a region with cheap electricity and/or cheap public charging. Perhaps someone is in an area cheap/expensive gasoline. The price comparison for someone in California is very different than for someone in Texas, which is very different than for someone in Washington.
It just make the calculation easier. It doesn't change energy used. It affects the traveling time somewhat and the money you pay for electricity.
Two years ago we did a road trip to Rochester, NY. This was before EA on the east coast. None of the rental places had a hybrid, or even a compact We ended up with a Nissan Altima, from Enterprise rental, for $248.68 total.
