Taycan optimal driving speed chart

[Raphie]

So long story short - 80 mile travel would take 1h 15mins @ 60mph, in one go
at 80mph it would take 1h + 15min charge - effectively the same time to get from A to B?

the missing link seems to be distance and SoC, as that determines IF, WHEN and how LONG you need to charge. But for speed v/s consumption this is usefull, ThnX

I would plot it as speed v/s distance: i.e. @ 60mph I can do 200miles, while at 80mph only a 160miles

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[tutis]

Wouldn’t it be better to take 800-1000 km? With 400 km I think you will always have only one charge stop at any speed. At 50 kmh you can do just under 400 km and at 200 kmh probably a bit more than 200 km.

800-1000kms is better indeed, but the algorithm logic becomes a bit tricky as it needs to calculate deterministically (as opposed to running some kind of Monte Carlo simulation) what is the optimal number of charge vs speed; e.g. do I do 3 stops and drive at full tilt, or do 2 stops and drive moderately, and then the last charge may only need to be a partial charge, thus saving time as well. There are too many degrees of freedom in the model at that point, it becomes combinatorial hell...
I'm taking a mental shortcut here and saying that past the first charge, the achievable average speed for the remaining part of the trip is the average speed achievable over an infinite distance with infinite number of stops (which is what the curves show)

So long story short - 80 mile travel would take 1h 15mins @ 60mph, in one go
at 80mph it would take 1h + 15min charge - effectively the same time to get from A to B?

the missing link seems to be distance and SoC, as that determines IF, WHEN and how LONG you need to charge. But for speed v/s consumption this is usefull, ThnX

I would plot it as speed v/s distance: i.e. @ 60mph I can do 200miles, while at 80mph only a 160miles

Not sure I follow why travelling at 80mph on 80mile journey would take 15 min charge; once you arrive at your destination you don't need to count the charging time (e.g. you go to a meeting, go to sleep, etc.). It won't be time spent waiting in the car.

To plot speed vs distance, you just take the consumption figures that are shown as input in the model and do battery capacity / consumption at given speed and that will give you range at that speed; e.g. 83kWh/(25kWh/100km @ 130 km/h)= 332 km of range at 130 km/h if you went from 100% to 0% with the battery.

The curves in the model however also take into account the time needed to charge as a tradeoff to driving at higher speed; if you drive faster you reduce the range, and you need to charge more often (which is time at which you are travelling at zero km/h), so the model tries to find the optimal point for driving speed for a given charging speed.

PS: just a mention about average charging speeds. Assuming for one second the Taycan can achieve average charging speed of 170kW to charge from 5% to 85% (implying a charging time of 23 minutes for a battery of 83kWh) , the truth is that we also need to consider the overhead time to get off the highway and for the charger to start charging and getting back on the highway. If that adds for example 5 minutes of overhead, the true achievable average charge rate will drop from 170kW to 141kW; the latter is the figure we should use when reading the chart.

 

[rs38]

even under perfect conditions like charger free, fast and directly at the road, it's nearly impossible to reach >150 kph


(hot conditions) 142 km/h averaged
https://newsroom.porsche.com/en/201...ce-run-nardo-long-distance-testing-18400.html

(rainy conditions) ~125 km/h averaged
https://www.auto-motor-und-sport.de...ite-24-stunden-75-jahre-auto-motor-und-sport/

but don't forget it's much easier to travel fast

(cheap 2l Opel Diesel) 201 kph averaged
https://www.iol.co.za/motoring/cars/opel-astra-cdti-sets-24-hour-record-1596879

 

[tutis]

even under perfect conditions like charger free, fast and directly at the road, it's nearly impossible to reach >150 kph

Yup, that's why the average achieved speed on my chart (y-axis) tops out at around 145 km/h even with 150kW average charge speed, which assumes perfect conditions. And having even faster charging on hypothetical Taycan v2 won't materially improve this average achieved speed.

Good to see that my chart matches a real-world experiment!

 

[Mac_Gaz]

Top job, very interesting. Thank you for sharing.

 

[Hirschaj]

I used ABRP to do a similar analysis back in June 2022. I wrote about it in this article... https://medium.com/@the.ev.newbie/what-everyone-should-know-before-they-buy-an-ev-1ba9095c15ba

You'll find the analysis in the section titled "Things that Affect EV Range"

 

[rs38]

Yup, that's why the average achieved speed on my chart (y-axis)

btw: Why did you name your axes with prefixed "µ"? You mean it like Ø ?

 

[TDinDC]

Yes, thank you Tutis for the great work.

I used to make similar comparisons with my previous Tesla Model X by plotting out various scenarios with ABRP and other apps, and then comparing with real life experiences.

In the Tesla Model X, I found that I could shorten my overall trip time, particularly on long trips (e.g., 10 hours) by actually keeping my speed to 55/60 mph rather than my preferred 70/80mph, which just seems to kill range on a model X.

In the Taycan, the higher speeds seem to have a much lower impact on range. When you combine that with the much shorter charging times, I catch myself frequently hitting triple digits without concern about range . . .

I would really like to see that sweet spot speed for a Taycan CT . . .

 

[tutis]

btw: Why did you name your axes with prefixed "µ"? You mean it like Ø ?

just an old habit from stats, commonly used for expressing means. Plus I have hardwired in my brain the shortcut for typing µ while I would have to look it up for Ø. but they mean the same thing

Also, Ø tends to be confused with zero in handwriting as people like me tend to "slash" the handwritten zero to avoid confusion with capital O. µ has a more distinct shape

 

[tutis]

Yes, thank you Tutis for the great work.

I used to make similar comparisons with my previous Tesla Model X by plotting out various scenarios with ABRP and other apps, and then comparing with real life experiences.

In the Tesla Model X, I found that I could shorten my overall trip time, particularly on long trips (e.g., 10 hours) by actually keeping my speed to 55/60 mph rather than my preferred 70/80mph, which just seems to kill range on a model X.

In the Taycan, the higher speeds seem to have a much lower impact on range. When you combine that with the much shorter charging times, I catch myself frequently hitting triple digits without concern about range . . .

I would really like to see that sweet spot speed for a Taycan CT . . .

the figures I have are for a Taycan CT 4 (my car). I would have to re-run cleanly at steady speeds to get the exact consumption readings; I wasn't very disciplined when I made the measurements as I was often flooring it, or hitting traffic for a mile or two, then flooring it again. The functionality is there though.

I can imagine the curves looking very different for Model X because of its larger frontal area compared to Taycan, don't know about drag coefficient differences though, as the higher charging speeds on Taycan, and the 2-speed gearbox on Taycan which lowers RPM at high speed (high RPM in electric motors generate Eddy currents which hurt efficiency – though am not an electrical engineer so my knowledge stops there). I'd be interested in running the curves for Model 3 (very efficient) – it may get very similar optimum speed to Taycan

 

[Boris]

Interesting stuff. I'm driving an E-Tron GT (so close to the 4S I believe) and created a log for two recent trips through Germany. Happy to share the data, as it perhaps is insightful:



These were two trips with, at the first 400km, a lot of traffic or bad weather, driving on winter tires with temperatures around 0 degrees.

I think, realistically, to achieve the average driving speed, you need to add 30-40km/h to the target you are driving due to traffic, road works, etc. So the sections where I did > 140km/h I was driving > 180km/h where traffic permitted. For the 130km for example I had cruise control at 160km/h.

I'm in my 3rd month of ownership, only winter months so still do not have a complete picture of the consumption. According to Audi onboard computer, I'm basically around 24,8kWh/100km on average with mostly Dutch traffic.

 

[XLR82XS]

Good stuff, keep it coming - although those of us based in the US will lose interest above 160 km/h. :-(

Not all of us.

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