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Spent an hour thinking about this.

Assumptions. 500 miles trip. Soc 10% to 55% so as to get the top 53kw charging rate. Efficiency 4.4 miles / kWh at 63mph, and is inverse proportional to square of speed.

Cut away the math equations. Here is the short version of the story.

80mph. 6 charges. 9.2hr. 183kwh.
75mph. 5 charges. 9.2hr. 161kwh.
70mph. 5 charges. 9.7hr. 140kwh.
65mph. 4 charges. 9.7hr. 120kwh.
60mph. 3 charges. 9.9hr. 103kwh.
55mph. 3 charges. 10.6hr. 72kwh.

Conclusion. I will continue to drive at 65mph. 30min more, $20 less. It is pretty expense and time consuming to drive EV for road trip.

-TL

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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.
 

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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.

120kwh total at 65mph. $30 or 10 gallons of fuel equivalent. The trip only takes 7.7 hours instead of 10 hours. A small gas car costs less. I meant EV is not really cheaper, especially when you drive fast. It is more expensive for sure if you don't get to charge at home.

Another conclusion. You can't arrive early by driving slower. But you may arrive at the same time.

-TL

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And the average U.S. fleet fuel economy is about half of a 50 mpg car...

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.
 

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Second thought. It may not be a good strategy to stay below 55% soc. Even at tapered down charging rate of 16kw, it is still equivalent to 70mph. I will rerun the numbers with different soc limits.

-TL

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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.

120kwh total at 65mph. $30 or 10 gallons of fuel equivalent. The trip only takes 7.7 hours instead of 10 hours. A small gas car costs less. I meant EV is not really cheaper, especially when you drive fast. It is more expensive for sure if you don't get to charge at home.

Another conclusion. You can't arrive early by driving slower. But you may arrive at the same time.

-TL

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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.
 

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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.
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.
 

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I have been assuming that the car has been charged to 55% leaving home. 120kwh is all from charging on the road. That makes the analysis easier.

-TL

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Nope. Going above 55% won't help total traveling time. But you can actually arrive earlier by driving slower if you always charge up to 80%. The charge time is about 1 hr.

-TL

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I have been assuming that the car has been charged to 55% leaving home. 120kwh is all from charging on the road. That makes the analysis easier.

-TL

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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.

It appears that you're trying to manufacture circumstances in which an EV would be more expensive to take on a long trip than an ICE car, but the numbers just don't support it.
 

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Efficiency at 65mph is 4.13 miles / kWh. 500 / 4.13 = 121 kWh. It charges 4 times. Each time is 27kwh. When it arrives, the soc is above 10%.

It is wrong for me to say that the total energy is from charging on the road. It does uses the charge from home charging.

The electricity expense for such trip is the 27*0.19+(121-27)*0.31=$34.

We good?

-TL

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Efficiency at 65mph is 4.13 miles / kWh. 500 / 4.13 = 121 kWh. It charges 4 times. Each time is 27kwh. When it arrives, the soc is above 10%.

It is wrong for me to say that the total energy is from charging on the road. It does uses the charge from home charging.

-TL

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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).

Say an ICE car with the Bolt EV's size and format got 40 mpg at freeway speeds (a stretch, but we'll go with it) at the national average $2.20 per gallon, the 500-mile trip would cost $27.50. I'm not seeing a huge difference in cost there, and that's after working very hard to put the ICE car in its best light.
 

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Ok. Let's do it the other way.

The car is charged to 55%. I drive 112 miles to 10%. Then I charge to back to 55%, and continue to drive. I do this 4 times. When I arrive with 23% soc. Does it work?

I almost bought a Hyundai accent for $15k instead of the bolt. It does 40mpg. With all the subsidies, I think I paid $23k for the bolt. $8k can buy 2700 gallons of gas, or over 100k miles. Not to mention, saving of 2 hours for each of the trip.

-TL

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Ok. Let's do it the other way.

The car is charged to 55%. I drive 112 miles to 10%. Then I charge to back to 55%, and continue to drive. I do this 4 times. When I arrive with 23% soc. Does it work?

I almost bought a Hyundai accent for $15k instead of the bolt. It does 40mpg. With all the subsidies, I think I paid $23k for the bolt. $8k can buy 2700 gallons of gas, or over 100k miles. Not to mention, saving of 2 hours for each of the trip.

-TL

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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.

As for the Hyundai Accent, you're talking about a significantly smaller car. The trunk area is over 3 cu/ft smaller than the Bolt EV's, and the Accent has far, far less capacity with the seats down.
 

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I have been assuming that the car has been charged to 55% leaving home. 120kwh is all from charging on the road. That makes the analysis easier.
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.
 

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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.
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.
 

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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?
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.

Every analysis is based upon assumptions. If I try to manufacture a case, like I was accused of, I could have assumed I live in an apartment with no home charging available.

-TL

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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.
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.

We drove up Rt 15, from central Virginia to Rochester, New York...just under 500 miles, with four stops, only one to "charge." We bought, and used 25 gallons of regular gas total, at ~$2.60 per gallon average. For the entire trip, we averaged 49 mph, and 40 mpg, $0.065 per mile. I never would have believed that land yacht was that efficient.

On the way back we pulled into a Dunkin Donuts for breakfast, and damned if it wasn't a Tesla Supercharger stop!

ICED SC 2.jpg

We could have easily done this trip with a Model 3, as there are many Superchargers along the route.

Last year, thanks to EA, we felt comfortable enough to attempt the same trip, with a side trip to Ithaca on the way back. The non-Tesla DC charging infrastructure was still a joke, but at least now the trip is doable...with luck.

1153.3 miles, 4.5 mi/kWh average, 251 kWh total.
 
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