#### Murse-In-Airy

##### Well-Known Member

- First Name
- Rod

- Joined
- Mar 5, 2021

- Messages
- 464

- Reaction score
- 1,145

- Location
- Chaumont, NY

- Vehicles
- Mach-E ER AWD

- Occupation
- Nurse

- Thread starter
- #1

I wanted to do a little testing on how speed effects efficiency in my AWD ER MME. I had a 260 miles drive today. All highway. The temperature was a constant 50 degrees +/- 2 degrees. There was no great elevation change along the route. Some up slope but with an equal amount of downslope within the same areas.

I drove the first 100 miles at 72 MPH resulting in 2.7 miles/kwh.

The second 80 miles I drove at 65 MPH resulting in 3.1 miles/kwh.

The last 80 miles I drove at 69 MPH resulting in 2.8 miles/kwh.

It’s not enough data points to plot an entire curve, nor were all other variables controlled for. But it does highlight how speed kills one’s range.

If I drive 72 MPH, my range will only be 237 miles. I can make the 260 mile drive in 3 hours and 36 minutes but I have to factor in stopping to add the 9 kwh I come up short. I could do that in less than 10 minutes at a fast charger, plus on/off highway times. Call it 16 minutes. Total time 3 hours and 52 minutes.

If I drive 65, my range will be 271. So I gain 34 miles of range by slowing down. I can make the entire 260 miles in 4 hours without charging.

If I go faster, I will get to my destination faster, but only by 8 minutes AND I’ve now had to buy 9Kwh at $0.47/kwh. So I will have spent $4.23 to save 8 minutes.

All in all, I guess it comes down to personal preference. Go faster, burn more fuel (even if your fuel is measured in Kwh) stop more, still get there in about the same amount of time. YMMV

I drove the first 100 miles at 72 MPH resulting in 2.7 miles/kwh.

The second 80 miles I drove at 65 MPH resulting in 3.1 miles/kwh.

The last 80 miles I drove at 69 MPH resulting in 2.8 miles/kwh.

It’s not enough data points to plot an entire curve, nor were all other variables controlled for. But it does highlight how speed kills one’s range.

If I drive 72 MPH, my range will only be 237 miles. I can make the 260 mile drive in 3 hours and 36 minutes but I have to factor in stopping to add the 9 kwh I come up short. I could do that in less than 10 minutes at a fast charger, plus on/off highway times. Call it 16 minutes. Total time 3 hours and 52 minutes.

If I drive 65, my range will be 271. So I gain 34 miles of range by slowing down. I can make the entire 260 miles in 4 hours without charging.

If I go faster, I will get to my destination faster, but only by 8 minutes AND I’ve now had to buy 9Kwh at $0.47/kwh. So I will have spent $4.23 to save 8 minutes.

All in all, I guess it comes down to personal preference. Go faster, burn more fuel (even if your fuel is measured in Kwh) stop more, still get there in about the same amount of time. YMMV