Extreme over predicted range!

[PJnc284]

What’s The Optimal Speed For An EV Road Trip? We Use Our 2023 Ford F-150 Lightning XLT To Find Out

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[Firn]

Very interesting,
I was going the right direction to be down wind, so that may be the missing bit.

ok geek out alert - some TLDR stuff follows. and some math.

Now I want to consider two scenarios - slower and no stop, vs faster but adding a stop to charge.
We lose travel distance while sitting charging, but this is a trade off with overall time to travel a route. Let's consider a 600km trip (375 miles) in my SR:

At low speed say 50km/hr the time to go 600km is 12 hours. But 'could' be done with one charge.

At 70km/hr the 600km drops to 8.57 hours but a SR would need to stop and charge:
say 70km/hr is 19kwh/100km: this means a stop to charge is required for a SR, 6 x 19 =114kWh required from 98kWh battery - 16kWh needed.
say the driver stops part way, after 300km, to charge up the required 16kWh they will need if they started with 100%.
on a 50kW charger this is 19.2 minutes of charging, let's call it 30-minutes including time to connect and get going again. Now the 600km trip is: 600km/70 = 8.57hrs plus 1/2 hr = just over 9 hours insteadd of 12 hours.

I find my target 108km/hr runs between 28-30 kWh/100, so now considering 600km trip:
6 x 30 = 180kWh required (98 +82) to charge 82kWh using a crappy 50kWh charger is 1.64hrs of charging time. And the driving time is now 6 hours for a total trip time of 7.64 hours. better than 9hours.

We should be able to calculate an optimal speed where total trip time is minimized (charging plus driving) assuming charging facilities are available. We can refine this for the speed of the charging facility - although DCFC are not constant charging speed due to thermal effects, making the math a bit more involved.

My last trip to Winnipeg I recall going about 120km/hr, 33kWh / 100km (as best I can recall).
at 120km/hr a 600km trip is now 5hrs but will take a total of 33 x 6 = 198kWh and two stops will be needed in a SR to charge up the extra 100kWh needed. 2 hours of 50kW charger time so 7 hours for the total trip. ie 38 minutes less than the 7.64 hours that it would take at 108km/hr.

With DCFC the total trip time will be less driving faster, as long as the chargers are available along the route. cost of the trip will be more though.

You can set your overage speed percent in A Better Route Planner, as well as your overhead (time spent setting up the charger) and it accounts for travel time to the charger from the main road.

I have done this a dozen times on various long distance routes and up to about 130% of the posted speed (91mph in a 70mph zone), driving faster gets you there faster. Even tried the other way, going down to about 80% of posted speed (56mph in a 70mph zone). Less charges, but still longer overall trip speed.

 

[inchman254]

What’s The Optimal Speed For An EV Road Trip? We Use Our 2023 Ford F-150 Lightning XLT To Find Out

While the overall premise of this article makes sense... go fast and charge more times vs go slow and charge less, I have some disagreements regarding methodology with the author. It makes me think he's just another ICEman who didn't really understand EVs and how they are normally used.... exclusively stopping and charging for 15 minutes on a road trip? But, I'll ease off a bit because both this article and the one it references for a range test were written over 2 years ago.

But, in the article, he suggests that air drag "dwarfs" rolling resistance. Even at high speed, rolling resistance makes up a third of all drag. Because rolling resistance does not change with speed, at the lower end... up to 50 mph, it makes up at least half of all drag... at 30 it makes up 2/3s. If only air resistance counted, you could get infinite distance just by going slower and slower. But you can't get much above 4 mi/kWh (no wind), no matter how slow you go.

It turns out that his premise that the sweet spot is between 70 and 80 would have been even more substantial, even with normal 10%-80% pit stops, if he hadn't disregarded rolling drag. It would have added another half hour of charging time to the 50mph trip. (With a 30 mph tailwind, 100 is even better!)

BTW ... at 65 mph the cost is $258. At 80, you save 2 hours and the cost is $353... plus speeding tickets and the half hour per stop it takes to deal with the cop ;-).

 

[RickLightning]

Wait, cost matters?

 

[NW Ontario Ford Lightning]

So, the take-away...
Drive as fast as permitted/weather conditions allow, will save total trip time, but add cost.
1. assumes chargers available along the route, within the range of the EV.
2. select faster chargers over slower available along the route when both are present.

 

[Firn]

For fun I ran ABRP for a trip from Bangor Main to Lakeland Fl (east coast, good charger availability). Total trip distance was around 1600 miles.

I used two different reference speeds in ABRP, one for continuously driving below the speed limit, and one continuously driving above the speed limit.

90% reference speed (63 in a 70)
Total trip time was 1 day 9 hours.
There were 8 charging stops with a total of 3hr 48 minutes of charging. Average drive time varied between 2 hours and 3 and a half hours but the rough average was around ~2.5hrs for each leg.

120% reference speed (84 in a 70)
Total trip time was 1 day 4 hours
There were 12 charging stops with a total of 5hr 53 minutes of charging. Average drive time between chargers varied between an hour and two and a half hours but a rough average was ~1.5 hrs.

So even though it added over two hours more of charging, plus 4 additional trips from the highway to the chargers (and back), and 20 minutes more of "setup" time at the chargers, it still trimmed 5 hours off the total trip time.

 

[NW Ontario Ford Lightning]

For long trips - do you guys pick times and places for meal stops = longer charging at those stops, then shorter 'breaks' inbetween for bathroom break/coffee while charging 15-20 minutes and back on the road, overnight stop at hotel with L2 charging for next day 100% soc to start off the trip again?

My wife likes to start early and then stop to eat breakfast a couple hours later. Then drive and short-stop until lunch time where we stop for at least 30-35 minutes about while we charge all we can get. More short-stops after lunch time. Then stop for the night and have 'late supper' ie about 7-8pm but chill, do shopping rest and go to bed early while the truck charges at a hotel - typically L2 charging over night.
The problem being hotels typically have very few chargers and you don't know ahead of time you will get a charger or they will be all taken.

Wondering what others do when planning a longer trip?

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