Highway Speed?

[GrabberBlueNitePony]

So I think one of my biggest frustrations that I have learned is that despite the Mustang name, going fast is just not good if you want to maintain range. But how fast is fast? It feels like most of the time in varying weather between 50-70 degrees F, for the 1200 miles I've had the car, I cannot get above 3-3.2 kwh/mi. I am in Northern Virginia, most of my driving is highway, usually 10-15 miles for my commute, or the occasional 35-45 miles if I have a longer drive into DC. Only time I get more efficiency is when I have traffic which makes sense. I typically drive between 65-70 mph and that in itself is annoying. I have always gone 75-80mph but since that is so bad for an EV (facepalm), I have gone slower. Just doesn't seem like the efficiency is that great even at 65-75 mph. This along with the horrendous GOM update that is all over the place makes it annoying to try to maximize range while still enjoying the "Mustang" aspect.

What do you guys usually drive at on the highway?

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[RickMachE]

You're not going to beat 3.0 on the highway. I just got back from a 2,960 mile trip and never saw 3.0 once.

 

[Guss-E 2021]

The Mach-E is a very nice car and BEV. It is not, however, the most efficient at speed (compared to something like an Ioniq 6 for example).

If you think about it, sports cars and muscle cars are not really marketed for their fuel efficiency. It is more about the driving experience. I think there is a place in the BEV world for such cars. The Mach-E is one such car to me.

To answer your question: I usually go between 70-75mph but I'm doing short highway jaunts 99% of my driving. So I'm okay with the level of efficiency.

 

[mkhuffman]

I set the cruise for 80 mph and go. The only time I drive slower is when I am struggling to make it to the next charging stop.

I assume you can charge at home, and your commute isn't long enough to use up the entire range, so just charge at home when you need to and don't worry about efficiency. It only really matters on long trips IMO.

On the highway at the speed I drive I get 2.4-2.5 mi/kWh. In the summer it is on the high side of that range, and in the winter on the low side. If I use a lot of E-Heat it will be measurably worse.

 

[JohnFoxeSheets]

I drive at whatever speed I want (and is appropriate to the conditions/safety - typically around 75 mph) and don't worry about maximizing efficiency. That said, I typically get about 3-3.2m/kWh in my (non-PE)GT when freeway /highway driving. (Less in San Francisco city driving due to the hills.) I generally don't use eHeat and instead use the seat and steering wheel heaters when needed.

 

[GrabberBlueNitePony]

I set the cruise for 80 mph and go. The only time I drive slower is when I am struggling to make it to the next charging stop.

I assume you can charge at home, and your commute isn't long enough to use up the entire range, so just charge at home when you need to and don't worry about efficiency. It only really matters on long trips IMO.

On the highway at the speed I drive I get 2.4-2.5 mi/kWh. In the summer it is on the high side of that range, and in the winter on the low side. If I use a lot of E-Heat it will be measurably worse.

I already know this, but just mentioning that E-Heat is brutal lol. I had to drive almost my whole 90% range a few days ago on a cold rainy day. On a 42 mile drive back home with projected 48 miles left, I was hitting the defogger on and off for like 2 seconds at a time so I didn't get stranded lmao.

 

[SpaceEVDriver]

I usually go a bit slower than the speed limit, in the right lane. Example: Most of the roads I do road trips on have a speed limit of 70 or 75 mph. If I go 70 instead of 75, it would take me approximately 126 minutes instead of 118 minutes to get to my first usual charging spot 147 miles away from home. Saving 8 minutes (~7%) on the road costs me about 10-15% more charging time at the charger (3-5 minutes). You're going to pay for the speed one way or another, just like every trip; it's just more noticeable in a car that's only carrying the stored energy equivalent to 2.75 gallons of gas.

I've done about half of my ~14,000 miles at highway speeds. I'm averaging 3.3 miles/kWh.

 

[superdave80]

On my commute (65mph speed limit) I drive 60, and on road trips I just drive the speed limit. I get great efficiency, but a lot of you on this forum would probably die of boredom driving the same speeds as me

I have free charging at work, so you may all wonder why I would drive so slow. The main reason is I keep my cars a long time (I had my '99 Mustang for 18 years), and I want to put as little wear as possible on the battery.

I was hitting the defogger on and off for like 2 seconds at a time so I didn't get stranded lmao.

Sometimes, depending on the temperature/conditions, I've found that just turning on the air (no e-heat) can defog the window. I usually try that first before hitting the e-heat.

 

[DennisD]

On my commute (65mph speed limit) I drive 60, and on road trips I just drive the speed limit. I get great efficiency, but a lot of you on this forum would probably die of boredom driving the same speeds as me

I have free charging at work, so you may all wonder why I would drive so slow. The main reason is I keep my cars a long time (I had my '99 Mustang for 18 years), and I want to put as little wear as possible on the battery.

Sometimes, depending on the temperature/conditions, I've found that just turning on the air (no e-heat) can defog the window. I usually try that first before hitting the e-heat.

I could not agree more.

The ole' adage of "Drive it like you stole it" should only apply if you actually stole the car. If you had to pay for the car, you should treat it very nice and gentle IMO.

Now while I think it is okay to "get on it" here and then, for the most part you should treat it to make it last a long time.

Nice post btw.

 

[GrabberBlueNitePony]

So how's the math work then? With a 91 usable kwh battery on my '23 ER AWD, using 3.1 kwh/mi * 91, the range is theoretically 282 miles, pretty close to the rated 290. I haven't actually topped it to 100% to see what the GOM says yet, but that calculation method seems right.

 

[RickMachE]

So how's the math work then? With a 91 usable kwh battery on my '23 ER AWD, using 3.1 kwh/mi * 91, the range is theoretically 282 miles, pretty close to the rated 290. I haven't actually topped it to 100% to see what the GOM says yet, but that calculation method seems right.

The math won't work that way all the time. In cold weather, less battery is available, and you get less miles per kilowatt hour. On the way down south, I could see I had like 87kW available, but when it was warm it showed 91kW.

91 x 3 = 273
87 x 2.5 = 217

 

[Maquis]

The math won't work that way all the time. In cold weather, less battery is available, and you get less miles per kilowatt hour. On the way down south, I could see I had like 87kW available, but when it was warm it showed 91kW.

91 x 3 = 273
87 x 2.5 = 217

If I may nitpick……

The math always works. But in order to get the correct answer, you have to use the correct operands. ???

 

[SpaceEVDriver]

My math works: I've driven 230 miles on a single charge at 60-65 mph (speed limit) with ~30% charge remaining at the end of the drive. That works out to 328 miles 100%-0% range. 7,000 feet to 4,000 feet to 8000 feet and back. Average outside temperature was <32 F.

 

[gordonf238]

To the OP, your frustration shouldn't be with EVs in particularl, but the physics of drag. These are the same whether you're driving an EV or an ICE. The difference is, in a ICE vehicle, you just don't notice the inefficiency of driving at 80mph. However, your MPG rate goes down significantly once you go faster than 55mph (give or take).

Simply put, aerodynamic drag at 80mph requires substantially more power to overcome than does driving at around 55mph. I say 55mph because for most vehicles, that's generally the most fuel-efficient speed. This obviously depends on the drag coefficient of the vehicle, which varies from design to design.

In a ICE car, you just pull over and get gas whenever you need it. As such, you generally don't notice how much gasoline you're burning at 80mph. EVs on the other hand give you an instant readout on your range, so this inefficiency is far more perceptible.

Heck, Geo Metro would top out at around 99mph. That speed was drag-limited. Meaning, you could be redlining that engine and it wouldn't get past 99mph, because every single one of its 55 horses would be pushing to keep you at that speed.

 

[21st Century Pony]

So how's the math work then? With a 91 usable kwh battery on my '23 ER AWD, using 3.1 kwh/mi * 91, the range is theoretically 282 miles, pretty close to the rated 290. I haven't actually topped it to 100% to see what the GOM says yet, but that calculation method seems right.

I also have an ER AWD, in my case an early 2022 Premium. And I'm in Arlington VA... we must be relative neighbors.

I have driven multiple times thru the West Virginia / Western Maryland mountains ("hills" to all you Californians haha) to see family in Louisville Kentucky. This Winter, I have also done two long trips from Louisville, one to Burlington Vermont and coastal New England and back in December literally during the Big Buffalo Freeze, and another one to the Apostles National Shoreline in northern Wisconsin on Lake Superior in February. As an aside, the Mach E AWD does just fine while ice racing off of Ashland on Lake Superior

All this to say, quite a bit of driving in the past three months in cold to very cold conditions.

BLUF: yes E-Heat eats juice. So does driving above about 64 MPH in the Mach E. So do significant elevation climbs. Cost of doin' business, in a way.

I found that my best, consistent compensation techniques are to warm a solid object rather than warming the air around it... sweatshirt, sometimes hat, definitely the heated seat and the heated steering wheel.

On long trips thru the mountains when the next charging station is a ways off and it's cold, I tend to use the right (truck) lane when climbing, and slow down. I make up for it on the downslope on the other side of the mountain. Seems to all even out in the end.

I also have FDRS-appropriate gear and update my Mach E as soon as updates pop up. I'm sure this helps rather than hurts my long range driving, for E-Heat, for better DCFC charging etc. etc..

I've always gotten this Winter to the next destination (charging station, feed trough, bed, etc.) Inshallah... despite often driving on roads unknown to me. My absolute FailSafe when things looked chancy... just slow wayyy down. This car will really conserve juice (as will an ICE car) when driven at about 30 - 35 MPH. It's an old trick, known for decades and decades. In a pinch, it's my standby Plan B.

Hope this is useful.

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