Range at high speeds?

[TDinDC]

The difference in the power consumption you are seeing may result from where you are measuring the power. For the system as whole P = F * v where P is the power in watts, F is the total drag force and v is the velocity. For similar cars, this should be similar. But if your power is measured as the draw from the battery for a given speed, P = V * A, then different motors and drive trains will use different amounts of power to achieve the same speed even if the cars have similar aero.

Yes, I was thinking this likely was one of the reasons. I was also wondering whether the air resistance coefficient is actually always constant across all velocities. I mean, it would not be if you have active aero features (e.g., GT3 RS), but could engineers optimize aero for a specific design velocity such that it is not necessarily optimized for slower or faster speeds? I understand that, absent active aero features, you probably could not get big enough variations to come near the impact of velocity since it is squared, but still interesting and it could change the user's perception of the impact of velocity (I mean, it would just be less efficient at lower speeds so you wouldn't notice the impact of velocity as you increase into the optimized zone for aero). I just think it would be awesome to have active aero features designed to decrease the impact of air resistance deploy automatically when you use range mode (e.g., wheel covers, splitters and dive planes)

Sponsored

 

[JimBob]

Yes, I was thinking this likely was one of the reasons. I was also wondering whether the air resistance coefficient is actually always constant across all velocities. I mean, it would not be if you have active aero features (e.g., GT3 RS), but could engineers optimize aero for a specific design velocity such that it is not necessarily optimized for slower or faster speeds? I understand that, absent active aero features, you probably could not get big enough variations to come near the impact of velocity since it is squared, but still interesting and it could change the user's perception of the impact of velocity (I mean, it would just be less efficient at lower speeds so you wouldn't notice the impact of velocity as you increase into the optimized zone for aero). I just think it would be awesome to have active aero features designed to decrease the impact of air resistance deploy automatically when you use range mode (e.g., wheel covers, splitters and dive planes)

A quick read on this, comes up with all kinds of interesting things and what Porsche (especially) and other manufacturers do to improve handling at different speeds. Here's a link that goes into more detail with references to Porschce

https://aviation.stackexchange.com/questions/89367/does-c-d-change-with-speed

From the link, for our purposes Cd is going to be constant as the car is a short body moving under ground effects. But active aero does change the Cd. The most obvious is the spoiler on the back. At low speeds it's retracted so all things being equal you get the best Cd. At high speeds where you get concerned about traction, it's raised so downforce is increased but Cd goes up.

You can list a bunch of things that Porsche does to improve aero and handling, including but not limited to

1. Wing
2. PDCC
3. Torque vectoring
4. opening and closing cooling vents

Probably someone with F1 experience, that pushes the envelope, can add more and explain why.

 

[TDinDC]

A quick read on this, comes up with all kinds of interesting things and what Porsche (especially) and other manufacturers do to improve handling at different speeds. Here's a link that goes into more detail with references to Porschce

https://aviation.stackexchange.com/questions/89367/does-c-d-change-with-speed

From the link, for our purposes Cd is going to be constant as the car is a short body moving under ground effects. But active aero does change the Cd. The most obvious is the spoiler on the back. At low speeds it's retracted so all things being equal you get the best Cd. At high speeds where you get concerned about traction, it's raised so downforce is increased but Cd goes up.

You can list a bunch of things that Porsche does to improve aero and handling, including but not limited to

1. Wing
2. PDCC
3. Torque vectoring
4. opening and closing cooling vents

Probably someone with F1 experience, that pushes the envelope, can add more and explain why.

Yes, all true. What is interesting to me is that the approach to aero will differ dramatically if you are optimizing driving performance (e.g., GT3 RS or even Taycan spoiler deployed for downforce) or range. For range, I could see wheel covers (which are not important for handling) and maybe panels that deploy from the back of the car to give it the boat tail shape (i.e., the opposite of the current spoiler).

 

[JimBob]

For range, I could see wheel covers (

Ahh, moon wheels.

Looking at my aero wheels, we are well on the way to getting back there.

 

[David Baldwino]

All very technical gents, nice work.
Keeping it a bit simpler, here is Tuesday evenings report on usage from my last 20 day road trip visiting friends and family in France and Spain.
1yr old TCT4S, full lady luggage and loaded fully ( light load pressure in 21in tyres - fool ! ) 2x people and dog.
Keeping to generally 138kmh / 86mph avoiding French fines and 180kmh / 110mph for the occasional hour of empty toll roads. Rest was sight seeing through cities, towns and villages hence much lower average.

Never mind aero....what kills batteries is yes, speed and secondly, elevation!!!

So, we set off with a +30km milage buffer on Waze however the motorway toll road climbed 3000ft in central France and we pulled in at the Ionity charger with just 1% left. Phew. Lesson learned, use the PCM and Waze as a backup.....and don't push it when the horizon starts to climb skyward.

 

[Jhenson29]

So, we set off with a +30km milage buffer on Waze however the motorway toll road climbed 3000ft in

That’s almost 7% battery energy on its own.

 

[cometguy]

I am much more interested in what people are getting for range when driving always < 45 mph (< 75 km/hr), because that is how I spend most of my days driving/commuting locally (i.e., not on highways at highway speeds). I can go a week without driving > 45 mph, driving every day. I suspect that most people drive < 45 mph most of the time, as well.

 

[Gru]

almost 2.8mi/kwh at 90 mph. that was last summer on a flat highway.
I find it more than decent

 

[herminal]

almost 2.8mi/kwh at 90 mph. that was last summer on a flat highway.
I find it more than decent

Exactly my experience as well.. just finished a trip ( 1600 km in Germany) 90% autobahn. I adhered to the speed limits and on the unlimited sections I tried to cruise at 170-190kph. Ofcourse this is not always possible because of traffic. Sometimes hitting vmax aswell (238kph , software limited ) and the whole trip gave me 270wh/km. Pretty impressive imho.

In an SUV this would be alot worse ( higher drag )

it’s also a charging monster. 10 minutes to go from 2% to 55% ?

when Charging to 80% I got a range of 240km.
In my home country 80% gets me around 350km of range so not a big hit for having some fun with these higher speeds.

I remember when I had a panamera it consumed around 33 litres of petrol / 100km when cruising at 240-280kph and the tank was empty after 240km.. so basically the same range

 

[Gru]

I'll go back to Germany soon.
I'll monitor the power required to drive at high speeds: I guess it doesn't need more than 50% of max. power. ì would be curious to know what max. speed it could reach if not software limited

 

[freeforall]

Based on my experience high speed is not a problem for the Taycan. It is more harsh accelerations that will have much more impact in draining the battery (no different from petroleum engine)
The fact that the Taycan has 2 gears seems to mimic a patrol engine for consumption vs usual EVs. I am always impressed to see how many Tesla on the highway driving at 110kph while the limitation is 130kph. I’ve never felt the need for that with the Taycan. I just drive it normally and if end up arriving to a charging station at 15% instead of 20% because I was driving very fast, I just don’t care as I know it will charge those 5% in 1 min
I always felt that I didn’t buy an EV I bought a Porsche.

 

[Crazymind]

I drive 120 miles at 85/90mph. Starting at 240 miles prediction, I end up with 25 miles left. Sometimes I push briefly to 100mph. It’s a pleasure to drive the Taycan at high speed. Hope one day technology will give us all we want.

 

[neilj007]

I got nearly 300 mile range on a recent 230 mile trip from Wiltshire to Yorkshire...but there were a couple of extensive roadwork stretches on the motorway limiting speed to 50mph. Temp was also a balmy 20 degrees...

 

[f1eng]

I got nearly 300 mile range on a recent 230 mile trip from Wiltshire to Yorkshire...but there were a couple of extensive roadwork stretches on the motorway limiting speed to 50mph. Temp was also a balmy 20 degrees...

Which wheels and tyres?
I knew when I chose them the 21" cross turismo wheels/ summertyres were probably the least aerodynamic choice but I have never seen over 3.0 and more normally around 2.6 ish on long runs.
The estate body has about 20% more drag too

 

[neilj007]

Which wheels and tyres?
I knew when I chose them the 21" cross turismo wheels/ summertyres were probably the least aerodynamic choice but I have never seen over 3.0 and more normally around 2.6 ish on long runs.
The estate body has about 20% more drag too

20" sport aero

Sponsored