Maximum speed driving cross country

[hemiarch]

So what is the minimum speed you guys still consider to be efficient supercharging? Assuming you have enough to make it to the next supercharger and staying means potentially leapfrogging that one to the following one. Let’s say for arguments sake that neither charger is faster, less busy, has better stuff to do or eat etc.
Drive away when it’s below 100kw? 75kw?, 150kw? Or what?

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[HaulingAss]

So what is the minimum speed you guys still consider to be efficient supercharging? Assuming you have enough to make it to the next supercharger and staying means potentially leapfrogging that one to the following one. Let’s say for arguments sake that neither charger is faster, less busy, has better stuff to do or eat etc.
Drive away when it’s below 100kw? 75kw?, 150kw? Or what?

It really depends upon what I feel like and what exists ahead. If I'm just trying to make time, I just charge enough to make it the next Supercharger I want to stop at. And that could be because it's a quick stop or maybe there is something there that makes me want to stop for more than the usual 15-23 minutes, generally a good place to get food.

If I don't want to think about it too hard, but I still want to keep moving, I just unplug when it tapers down below 100 kW. If you are in a large area with sparse Superchargers, you might wait until it tapers to 60-80 kW.

 

[hemiarch]

Yeah. Around 100kw feels pretty close to the bang for the buck inflection point to me too.
And by buck I mean time spent.

 

[Outdoors]

Yeah. Around 100kw feels pretty close to the bang for the buck inflection point to me too.
And by buck I mean time spent.

100kW is what I use on my S. I would hazard maybe a little higher on the CT. Only a few places in the west that speed and distance overlap charging speed. What I mean there are some places in the West where it makes sense to drive slower with the CT, as the time spent charging would be significantly longer if one drives the speed limit. The distances are a little too great to truly do splash and dash. I would imagine those gaps will decline over time.

Just download the charging curve which is published on the CT. When it flattens move on. Yet if the next charger sucks or is far off the road one starts to make some guesses. Really depends on how serious people want to get. I can say if one is sitting at 50kW and doing charger after charger one is going to be in for a long trip. Still requires a little forethought if one really wants to try to compete in the ICE world.

 

[HaulingAss]

Ok, updated the model using 535 wH/mi @ 82.5 mph. Moves the "optimum" cruise speed up to 93 mph assuming 5 min from exit to on charge, 20% to 80% charging (average 150 kW delivery rate on SC3) for 29.5 minutes. Does anyone have any high speed wH/mi data?

Yeah, but who regularly drives around for 5 minutes before plugging in? Sure, it can happen, but it's not typical. When I'm road-tripping I prioritize locations that have less than a minute or two between exiting the highway and plugging in. On well-travelled routes this is common.

Also, who keeps the SOC between 20% and 80% on a road-trip? Experienced EV road-trippers know their are big time savings to be had by not being afraid to go below 20% SOC (and also by unplugging before reaching 80%).

You speak of charging for half an hour (29.5 minutes). I've been EV road-tripping for years (including in the Cybertruck) and I can only think of one location I've charged for 30 minutes or more (when not eating or doing other desired activities), and that was on a rural Montana route to a Supercharger black hole where I would be spending a day or two before returning. Guess what? Tesla has eliminated that Supercharger "black hole" by installing an 8-stall 250 kW station. Now a 12-15-minute charge is all that is necessary. This is the way of EV road-tripping if you like to keep charging a minimal time component.

 

[Gaximus]

Just did a 800 mile trip at 84, it was the quickest time I’ve made the trip. I do the trip twice a year, and was doing it in my model S before at a lower speed because I thought saving range will save charging times.

I saw on here somewhere someone had done the math, on speed vs total time vs distance. And it was somewhere around 94 mph, where the time saved by speeding is neglected by the time waisted by charging. i don’t think it included time to get off the highway, but that has to happen either way so doesn’t really matter. Just try to keep your battery between 10-60%, and you‘ll get the most benefit of faster charging.

 

[Gaximus]

Ok, updated the model using 535 wH/mi @ 82.5 mph. Moves the "optimum" cruise speed up to 93 mph assuming 5 min from exit to on charge, 20% to 80% charging (average 150 kW delivery rate on SC3) for 29.5 minutes. Does anyone have any high speed wH/mi data?

I don’t think the 5 min from the exit matters in the equation. You will have to stop either way to charge. Unless you go so slow to eliminate a charging stop.

 

[Hazard One]

Yeah, but who regularly drives around for 5 minutes before plugging in? Sure, it can happen, but it's not typical. When I'm road-tripping I prioritize locations that have less than a minute or two between exiting the highway and plugging in. On well-travelled routes this is common.

Also, who keeps the SOC between 20% and 80% on a road-trip? Experienced EV road-trippers know their are big time savings to be had by not being afraid to go below 20% SOC (and also by unplugging before reaching 80%).

You speak of charging for half an hour (29.5 minutes). I've been EV road-tripping for years (including in the Cybertruck) and I can only think of one location I've charged for 30 minutes or more (when not eating or doing other desired activities), and that was on a rural Montana route to a Supercharger black hole where I would be spending a day or two before returning. Guess what? Tesla has eliminated that Supercharger "black hole" by installing an 8-stall 250 kW station. Now a 12-15-minute charge is all that is necessary. This is the way of EV road-tripping if you like to keep charging a minimal time component.

29.5 minutes is how long a 250 kW charger takes to go from 20% to 80%. Your stops are shorter since you plan around being sub 20% on arrival and charging to ~60%. 5 minutes to exit highway, park in spot, plug in, unplug, drive back to highway, and get up to speed. Seems not enough to be honest. Some chargers are not located immediately off the highway, or get caught at a red light, or a line of cars waiting to get on the highway...etc etc. It's an analytic assumption...just a number that can easily be changed. Planning to be below 20% can be risky if you run into high winds in the desert as you ride along, which, even though I'm a newbie, has happened to me...went from planning to arrive at 25% charge to an actual 10% on arrival. Had I planned for 15% on arrival could have been bad. That said, clearly it's advantageous from a time perspective to do as you say: arrive low and depart early. I wish the built in Tesla route planner would allow you to set an arrival energy at the next charging stop. Maybe some of the third party apps do this? Which one do you recommend?

 

[hemiarch]

29.5 minutes is how long a 250 kW charger takes to go from 20% to 80%. Your stops are shorter since you plan around being sub 20% on arrival and charging to ~60%. 5 minutes to exit highway, park in spot, plug in, unplug, drive back to highway, and get up to speed. Seems not enough to be honest. Some chargers are not located immediately off the highway, or get caught at a red light, or a line of cars waiting to get on the highway...etc etc. It's an analytic assumption...just a number that can easily be changed. Planning to be below 20% can be risky if you run into high winds in the desert as you ride along, which, even though I'm a newbie, has happened to me...went from planning to arrive at 25% charge to an actual 10% on arrival. Had I planned for 15% on arrival could have been bad. That said, clearly it's clearly advantageous from a time perspective to do as you say: arrive low and depart early. I wish the built in Tesla route planner would allow you to set an arrival energy at the next charging stop. Maybe some of the third party apps do this? Which one do you recommend?

It does allow that. Say you’re navigating to Vegas and there is a planned stop at white hills, you can navigate to white hills and set the arrival energy to whatever you want.

 

[Hazard One]

I don’t think the 5 min from the exit matters in the equation. You will have to stop either way to charge. Unless you go so slow to eliminate a charging stop.

The stop "admin" time matters on long cross countries where the total number of stops is different when comparing different speed strategies. For instance, on a 1000 mile trip driving 60 mph (315 Wh/mi), you can "get away" with stopping 4 times. But at 90 mph (634 Wh/mi) you'll end up stopping 9 times using 15% arrival, 69% departure as the charging strategy. Well, that is assuming the accuracy of the Wh/mi numbers!

 

[Beetlebug62]

When I got my Model 3 in 2018, I ran simulations, that use real-world data, on ABRP. And, I did a trip from Maine to Denver and back. 4400 miles. Basically, what you learn is the fastest roadtrip is to drive as fast as you are comfortable with, and charge at the lowest SOCs you are comfortable with.

And for me, that was 8-10mph above the speed limit, and charge at 10-15%, typically up to ~65%. My nephew just drove from my home to Denver, 2200mi in 2 ½ days, in my 2018 Model 3.

So, I just punched in a Manhattan to Manhattan Beach trip, and the maxim still holds for Cybertrucks as it does for the Model 3, drive as fast as you are comfortable with. The speed more than makes up for the additional charging.

View attachment 106830
If you do a little math, you'll see that the average driving speed is 86mph, and average legs are 97miles, and average charging stops are 19 ½ mins.

Edit: yes, I added 2 mins to each stop for "overhead". ABRP allows you to add that extra time to and from the charger. Typically you choose ones with easy-off, easy-on.

 

[Beetlebug62]

Here's a chart I made for my passengers to help them understand the charge taper. For me, the CT taper matches my 2018 Model 3, when they reach about 30%. I typically feel like going when I get to the 65-70% range, as that's where it crosses below 100kW. Starts to feel slow. I mean, I've typically added 50-60%, plenty for me to go 150+mi before my next bathroom stop.

 

[dalton108]

the 800 Wh/mi figure came from searches on the net and this forum...but, would love to tweak in the model with good data! Lemme re-run using your figure of 535 wh/mi at 82.5 mph....

Traveling on my way to SoCal in the rain with winds that must’ve been head-on I was seeing around 700 Wh/mi average traffic speed was around 75. These were some of the highest numbers I’ve ever seen. On the return trip in clear less windy conditions traveling at around 80+ I was seeing about 530 to 560 if that date point helps.

 

[Hazard One]

Here's a chart I made for my passengers to help them understand the charge taper. For me, the CT taper matches my 2018 Model 3, when they reach about 30%. I typically feel like going when I get to the 65-70% range, as that's where it crosses below 100kW. Starts to feel slow. I mean, I've typically added 50-60%, plenty for me to go 150+mi before my next bathroom stop.

Very cool chart! Questions: what is the lower blue line,, is there a Cybertruck V3 line?

 

[HaulingAss]

I wish the built in Tesla route planner would allow you to set an arrival energy at the next charging stop. Maybe some of the third party apps do this? Which one do you recommend?

The Tesla navigation app does allow you to set an arrival energy. Check the Owner's Manual.

I only use the included Tesla apps when I travel. The only real reason to use non-Tesla apps is if you wanted and/or needed to use third-party charge networks to accomplish your trips. i don't want to put up with them, and I don't need to, so I only use Tesla apps and the Supercharger Network.

Sure, if I had to do a trip that was out of the ordinary for me, I would use third-party DCFC networks. Thankfully, in 8 years that hasn't been necessary.

The two apps I use are the standard Nav app, properly configured, and the Trip Energy/Efficiency app, to get the best estimates of arrival energy and track my actual consumption periodically along the route. It's amazingly accurate 95 percent of the time and alerts me early when things are not going as expected. This allows me to arrive with very low states of charge without undue concern.

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