Is the Mach E a viable long range daily commuter?

dbsb3233

Well-Known Member
First Name
TimCO
Joined
Dec 30, 2019
Threads
54
Messages
9,299
Reaction score
10,814
Location
Colorado, USA
Vehicles
2021 Mustang Mach-E FE, 2023 Bronco Sport OB
Occupation
Retired
Country flag
Look at the table below to see how you can increase range by slowing down. But if you absolutely have to drive at 75 mph even those few weeks a year that it is really cold than I guess BEV is not for you.
1610995749207.png
Looks like most of those are showing 18% less efficiency at 75 MPH vs 65 MPH. That's more consistent with what I've been reading. 40% sounded excessive.
 

DBC

Well-Known Member
First Name
Don
Joined
Oct 1, 2020
Threads
8
Messages
1,224
Reaction score
1,428
Location
San Diego
Vehicles
Volt ELR
Country flag
Looks like most of those are showing 18% less efficiency at 75 MPH vs 65 MPH. That's more consistent with what I've been reading. 40% sounded excessive.
You're conflating total energy with energy to overcome drag. Those are two different things. While the energy needed to overcome drag is the main factor at higher speeds it's not the only factor. Put another way, one component going up 40% doesn't mean the whole thing goes up by 40%. In this regard you can easily compute that the power needed to overcome drag goes up by 40% when going from 65 MPH to 75 MPH. I gave you an example that goes through the math. There are plenty of others. These calculations do not depend on whether the vehicle is powered by an engine or a motor. Drag is drag, and the power needed to overcome drag is the power needed to do that. I understand your point that drive train efficiency and gearing might effect these results, but we're dealing with a single reduction gear and a back of an envelope calculation.

If you don't like calculations and prefer charts, they also demonstrate that the energy saved by having the heater run for less time won't begin to make up for the energy expended when increasing speed. A heater running continuously at 2000 watts for an hour consumes 2 kW. Hence a vehicle traveling 75 MPH will use 26.667 Wh/mile and a vehicle traveling 65 MPH will use 30.7692 Wh/mile. That's a difference of 4.1 Wh/mile. If you look at the Musk/Straubel blog they claim going from 65 MPH to 75 MPH increases consumption by 50 Wh/mile for the Model S (this is best case since the aero on the MME won't be as good and very close to my initial estimate of 5 KWh increase in power to overcome drag). Since 50>4, energy consumption related to speed will dwarf energy savings attributable to running the heater for a shorter period of time. https://www.tesla.com/blog/model-s-efficiency-and-range

Note this highlights not only the energy penalty of going faster but also the energy savings offered by heated seats.
 
Last edited:

dbsb3233

Well-Known Member
First Name
TimCO
Joined
Dec 30, 2019
Threads
54
Messages
9,299
Reaction score
10,814
Location
Colorado, USA
Vehicles
2021 Mustang Mach-E FE, 2023 Bronco Sport OB
Occupation
Retired
Country flag
Put another way, one component going up 40% doesn't mean the whole thing goes up by 40%
That's exactly my point. It's about more than just drag.

And why the other actual BEV examples noted lose a lot less than 40% between 65 and 75 MPH. 18% and 25% are still a lot, but they're well short of 40%.
 

Dan G

Well-Known Member
First Name
Dan
Joined
Dec 11, 2020
Threads
0
Messages
87
Reaction score
116
Location
Detroit
Vehicles
Hyundai Ioniq
Occupation
Pilot
Country flag
So under the theory "you don't drive cars on paper," I took my Ioniq out tonight for a 120 mile drive.

It was 31F, calm wind and it was night. I kept my cabin temp at 70F and my heated seat on low. I drove the first half of the 60 mile leg at 75 then slowed to 65. (Mostly because I entered Ohio.) And I reversed it coming back.

The heater drew 1.6 to 2.2 kW the entire drive. I did preheat the car. The 75mph legs, the motor averaged around 20kW. My driving efficiency was 2.9 mi/kWhr. For the 65mph legs, the motor averaged 12kW. My efficiency was 3.5 mi/kWhr.

Take from that what you will.
 

dbsb3233

Well-Known Member
First Name
TimCO
Joined
Dec 30, 2019
Threads
54
Messages
9,299
Reaction score
10,814
Location
Colorado, USA
Vehicles
2021 Mustang Mach-E FE, 2023 Bronco Sport OB
Occupation
Retired
Country flag
So under the theory "you don't drive cars on paper," I took my Ioniq out tonight for a 120 mile drive.

It was 31F, calm wind and it was night. I kept my cabin temp at 70F and my heated seat on low. I drove the first half of the 60 mile leg at 75 then slowed to 65. (Mostly because I entered Ohio.) And I reversed it coming back.

The heater drew 1.6 to 2.2 kW the entire drive. I did preheat the car. The 75mph legs, the motor averaged around 20kW. My driving efficiency was 2.9 mi/kWhr. For the 65mph legs, the motor averaged 12kW. My efficiency was 3.5 mi/kWhr.

Take from that what you will.
Thanks. That's curious in itself because the motor draw difference doesn't seem to line up with the miles/kWh difference. The heater explains a little of that but not anywhere near that big of a gap. Odd.

Bottom line though are the miles/kWh numbers. Those are what really count for actual range. And that's showing ~20% more moving from 65 to 75 MPH. Pretty consistent with the Bolt and Tesla charts.

I was hoping it would be closer to 10% in the MME, but looks like I'll have to set initial expectations to 20% worse at 75 until I can test it for real.
 


Dan G

Well-Known Member
First Name
Dan
Joined
Dec 11, 2020
Threads
0
Messages
87
Reaction score
116
Location
Detroit
Vehicles
Hyundai Ioniq
Occupation
Pilot
Country flag
Bottom line though are the miles/kWh numbers. Those are what really count for actual range. And that's showing ~20% more moving from 65 to 75 MPH. Pretty consistent with the Bolt and Tesla charts.
I should have added my car has a 28 kWh battery. So it's about a 15% difference in range. (84 vs 98 miles.)
 

mr_raider

Well-Known Member
Joined
Dec 22, 2020
Threads
8
Messages
428
Reaction score
318
Location
Montreal, QC
Vehicles
2021 Mustang Mach-E Select AWD
Country flag
Thanks. That's curious in itself because the motor draw difference doesn't seem to line up with the miles/kWh difference. The heater explains a little of that but not anywhere near that big of a gap. Odd.

Bottom line though are the miles/kWh numbers. Those are what really count for actual range. And that's showing ~20% more moving from 65 to 75 MPH. Pretty consistent with the Bolt and Tesla charts.

I was hoping it would be closer to 10% in the MME, but looks like I'll have to set initial expectations to 20% worse at 75 until I can test it for real.
Miles per kwH is an inverse function measure like Mpg. To observe proportionality you need to look kwH per mile travelled.
 

dbsb3233

Well-Known Member
First Name
TimCO
Joined
Dec 30, 2019
Threads
54
Messages
9,299
Reaction score
10,814
Location
Colorado, USA
Vehicles
2021 Mustang Mach-E FE, 2023 Bronco Sport OB
Occupation
Retired
Country flag
Miles per kwH is an inverse function measure like Mpg. To observe proportionality you need to look kwH per mile travelled.
Whether they're "inverted" or not just depends which side of the equation you're looking at it from. I know some prefer distance per power, others prefer power per distance. I prefer the former, perhaps because I'm so used to MPG. But that's also how I usually apply the measure in a practical sense ("How many miles can I make it on X amount of fuel?").

It's the same ratio whether you 1/x them or not. Although as with any ratio, it depends on whether you're looking for "What % of A is B?" or "What % of B is A?".
 

mr_raider

Well-Known Member
Joined
Dec 22, 2020
Threads
8
Messages
428
Reaction score
318
Location
Montreal, QC
Vehicles
2021 Mustang Mach-E Select AWD
Country flag
Whether they're "inverted" or not just depends which side of the equation you're looking at it from. I know some prefer distance per power, others prefer power per distance. I prefer the former, perhaps because I'm so used to MPG. But that's also how I usually apply the measure in a practical sense ("How many miles can I make it on X amount of fuel?").

It's the same ratio whether you 1/x them or not. Although as with any ratio, it depends on whether you're looking for "What % of A is B?" or "What % of B is A?".

Yeah but be careful.

BEcause it's an inverse ratio it gives an impression of distortion at extremes. The difference between 15mpg to 25mpg is much more than 40mpg to 50mpg.
 
  • Like
Reactions: ARK

dbsb3233

Well-Known Member
First Name
TimCO
Joined
Dec 30, 2019
Threads
54
Messages
9,299
Reaction score
10,814
Location
Colorado, USA
Vehicles
2021 Mustang Mach-E FE, 2023 Bronco Sport OB
Occupation
Retired
Country flag
Yeah but be careful.

BEcause it's an inverse ratio it gives an impression of distortion at extremes. The difference between 15mpg to 25mpg is much more than 40mpg to 50mpg.
Those produce different %improvements, yes. But not because of inversion. Invert them from MPG to GPM and you still get the same 67% improvement on the first and 25% improvement on the 2nd.
Sponsored

 
 




Top