Why do EV's in general have poor top speed

Rt1AWD

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I agree. For Germans it is an issue
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Mach1E

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I agree. For Germans it is an issue
Or anyone who wants to take the car to a track or drag strip (like myself).

The point of the article was just using facts in light of your “there is a reason for speed limits” comment.

Unless I assumed incorrectly that you were referring to some sort of safety aspect? Data proves otherwise.
 

buzznwood

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There is a reason for speed limits
My favorites are the speed limits that suddenly go +/5 mph on the exact same piece of straight road as I cross a state boundary in the middle of nowhere. So one has to assume the + state must use a road surface with more magical properties ? as there is zero difference in conditions ;)

The problems with limits based on some arbitrary number thinking is it depends on what state / country you happen to be in where you are driving, the true limit is really imposed by the actual driving conditions where at times driving to the speed limit would be dangerous.

While I look back fondly of my times on driving down the autobahn at 165+ in the early 90's and been one of the slow cars lol, and while there are highways that could safely tolerate those speeds over here there also plenty that are falling apart and lack the relevant crash barriers to the point that 70 is pushing it

As a lot of of modern vehicle can happily sit all day at 100 without issue maybe when the infrastructure finally gets some much needed TLC the interstate and its random collection of limits can be updated and better suited to match the capabilities of modern vehicles.
 

Rt1AWD

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Or anyone who wants to take the car to a track or drag strip (like myself).

The point of the article was just using facts in light of your “there is a reason for speed limits” comment.

Unless I assumed incorrectly that you were referring to some sort of safety aspect? Data proves otherwise.
Of course it is a safety aspect. Although speed itself is not the crucial factor here.... the humans are......
 

devmach-e

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I don't understand, why there is no some sort of Overdrive mode on EV's that would work like second gear or something.
Cost and complexity of designing a multi-speed transmission for the EV is the main reason. And it really comes down to a cost/benefit analysis. We have multi speed transmissions in conventional cars because internal combustion engines for the most part have a very narrow power band. Multiple gears is how we wring as much power out of those engines while propelling the car down the road while still being efficient.

But the electric motor is different. It has all the torque available at 0 RPM, and has a very wide power band where it can make most of its HP and still have maximum torque. No real need for a multi-speed transmission. Just one reduction gear necessary to keep the electric motor RPMs in a safe/efficient range for the car’s speed. There are multi-speed transmissions available for some EVs, but those EVs tend to cost at least double or triple the price of the highest end Mach E.

Now, some EV manufacturers have figured out how to emulate a multi-speed transmission by using multiple motors on the drive axel(s), and only energizing the appropriate motor at the appropriate time. Some have even employed a clutch to completely isolate the non-operating motor from the wheels. But this then starts to encroach on the complexity issue with a conventional multi-speed transmission.

Would a two or three gear transmission in an EV make it go a bit further on the same battery pack as a single gear? Absolutely. The question is, how much would it cost for how much extra range. Is the extra weight of the transmission less than a slightly larger battery pack that would allow the car to the same extra number of miles?
 


Mach1E

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Cost and complexity of designing a multi-speed transmission for the EV is the main reason. And it really comes down to a cost/benefit analysis. We have multi speed transmissions in conventional cars because internal combustion engines for the most part have a very narrow power band. Multiple gears is how we wring as much power out of those engines while propelling the car down the road while still being efficient.

But the electric motor is different. It has all the torque available at 0 RPM, and has a very wide power band where it can make most of its HP and still have maximum torque. No real need for a multi-speed transmission. Just one reduction gear necessary to keep the electric motor RPMs in a safe/efficient range for the car’s speed. There are multi-speed transmissions available for some EVs, but those EVs tend to cost at least double or triple the price of the highest end Mach E.

Now, some EV manufacturers have figured out how to emulate a multi-speed transmission by using multiple motors on the drive axel(s), and only energizing the appropriate motor at the appropriate time. Some have even employed a clutch to completely isolate the non-operating motor from the wheels. But this then starts to encroach on the complexity issue with a conventional multi-speed transmission.

Would a two or three gear transmission in an EV make it go a bit further on the same battery pack as a single gear? Absolutely. The question is, how much would it cost for how much extra range. Is the extra weight of the transmission less than a slightly larger battery pack that would allow the car to the same extra number of miles?
I think I read the 2 speed for Porsche adds about 5% efficiency.

Maybe worth it at Porsche prices, not so much at Ford prices.
 
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2021mustangdan

2021mustangdan

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I now understand the reason " why " top speed in general is lower in EV's compared to ICE Mustangs I have owned in the past. One speed transmission + rpm of electric motor determines the top speed.

In the past there was times when passing on highway ,I have exceeded the 112 mph top end of the Mach-E. So will have to be more careful in the future.
 

devmach-e

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You forgot the multi-phase engine like what is used in the Tesla Model S.
All modern electric motors used in EVs are multi-phase. Whether they are induction or permanent magnet motors is another thing.
 
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2021mustangdan

2021mustangdan

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All modern electric motors used in EVs are multi-phase. Whether they are induction or permanent magnet motors is another thing.
I do not know how whether they are induction or permanent magnet affects them in automotive use. What are advantages and cons of each design?
 

devmach-e

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All Hat No Cattle

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Gixxer750

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Of course it is a safety aspect. Although speed itself is not the crucial factor here.... the humans are......
Bingo. The major difference between US and Germany is driver training. Compare the requirements and it will make sense why the Autobahn is still feasible there. It's not only about speed but situational awareness and lane etiquette. You don't see a beat up pick up truck parked in the left lane going 10mph under the limit over there.
 

Rt1AWD

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Bingo. The major difference between US and Germany is driver training. Compare the requirements and it will make sense why the Autobahn is still feasible there. It's not only about speed but situational awareness and lane etiquette. You don't see a beat up pick up truck parked in the left lane going 10mph under the limit over there.
So there is a reason for all those speed limits ;)
 
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2021mustangdan

2021mustangdan

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Found the a**hole.
On Hwy 401 near Toronto traffic is already 95 mph average at times so you think if passing that you only need 97 mph ? Never suggested staying at 115 mph but get by as quick as possible and back in your own lane
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