The powers of EV's

[robinessex]

Undercover McNoName said:

Crossposting from another thread. Essexrobin, it’s not the 1950’s anymore.

robinessex said:

hurstg01 said:

When mine faffs, things get reorganised / put in a different place [for no reason apart from 'the hell of it' from what I can see].

So we have 3 house phones dotted round the house for ease [Kitchen, Hallway, our bedroom], but MrsH decided without consultation [as is often the way] that "we" didn't need one in the bedroom anymore, so turned the charger off at the wall and stored it in the loft in its original box

What she didn't reckon on was that, although the charger was turned off, the phone was still charged and would charge down over time. Cue last night, 11pm, and every other minute a fairly soft 'beep.......................................beep' could be heard. We discussed this in the dark in whispered tones so as not to wake the children, and assumed it was one of the neighbours smoke alarm batteries running out - annoying but they'd eventually hear it themselves and sort it out - they're good neighbours so we let things like this slide

1am - let the dog out for its nightly ablution and still heard it.
4am - light sleep awoken by the noise
5am - couldn't sleep any more so was wide awake til 6 when I take the dog out for its morning walk

8am - after the dog walk and my shower, we were in our bedroom and I could still hear the beeping; MrsH 'couldn't hear it' but my daughter could and suggested it sounded like a phone running out of battery, to which MrsH suddenly remembers her tidying yesterday and opens up that perhaps its the phone she took out of the bedroom and stored in the loft....

For f's sake....

Put a oneway latch on the loft, the next time she ventures there, she won't be able to get out

I guess jokes are lost on you then.

[robinessex]

Undercover McNoName said:

robinessex said:

I guess jokes are lost on you then.

This is a fun one too, in the context of this thread. Keep dreaming in the nursery home, while yelling at passing EVs.

robinessex said:

I'm hoping that all EV's come with auto speed limit control, thus they'll all be confined to the inside lane of a motorway as they won't be able to overtake each other. The outside lane(s) will now be totally traffic free for us old gits in our ancient ICE horseless carriage to proceed at a leisurely 1 lepton or faster, all the speed cameras having been mothballed long ago.

With future 'big brother' controls and software on new cars coming, it may well be the future quite shortly. Now, where did that PH "Speed Matters" logo go?

[robinessex]

Puzzles said:

Swmbo has never crashed my M3 P. They’re easy to drive so it isn’t an issue.

Only on PH could someone try to spin quick acceleration into a negative for EV.

I never said it was a negative, but 1g acceleration on the road? I've experienced that, and it is bloody dramatic. If you did that and wasn't prepared for it, you'd be in trouble before you knew what happened. I do indeed hold the view that a powerful car, well-driven, can actually be a safer vehicle.

[robinessex]

GT9 said:

robinessex said:

I'm guessing that's what I enquired about, the motor control system limits current and volts. An electric motor will draw much more current when stalled than when running. This is because when running, it is also acting as a generator, creating an EMF which opposes the applied EMF and reduces the overall current. A DC compound motor can run in series or shunt configuration, a bit like underground trains do. IN a DC shunt motor, torque is proportional to armature current. For a series-wound DC motor, torque increases as the square of the armature current.

EV traction motors are controlled by power electronics, aka, variable frequency drive.

The drive draws DC current from the battery, inverts it using high-frequency switched transistors to produce synchronous (or asynchronous) AC excitation of the motor stator windings.

The back-emf of the rotating magnetic field on the rotor can be produced in several way, either using induction, permanent magnets or a wound field rotor with brushes. There are several configurations in use.

The drive is controlling the current, and thus the torque of the motor, there is no inrush current or stall scenario to worry about.

The motor torque output is controlled at a quasi-fixed value from zero speed up to the constant power speed.

The power output therefore rises linearly from zero speed to the constant power speed.

The purpose of this is to match what is required for constant acceleration of a fixed mass object, i.e. a linear increase in power from zero speed.

This results in a fixed torque at the driven wheels that provides a constant accelerative force, as you alluded to earlier.

In the Tesla Plaid the constant power speed is geared to be at around 60 mph.

Above that, the torque decays, leaving a quasi-fixed power output.

Appreciate that, I'm afraid my memory from college on electrical stuff is a bit out of date and limited.

[robinessex]

Muzzer79 said:

robinessex said:

Puzzles said:

Swmbo has never crashed my M3 P. They’re easy to drive so it isn’t an issue.

Only on PH could someone try to spin quick acceleration into a negative for EV.

1g acceleration on the road? I've experienced that, and it is bloody dramatic. If you did that and wasn't prepared for it, you'd be in trouble before you knew what happened.

But why do you think people will be unprepared for it?

It's not like people are just getting in a random Tesla on the street that they know nothing about and setting off.

People buy cars. They take note of the specification, which is also explained to them by the vendor. If you go to the trouble of speccing an EV with 1000bhp, it won't be a surprise that it's very, very fast.

People will consequently brief whoever else drives it that it's very, very fast.

This is no different to someone who buys a BMW M5, for example. They know it's a fast car - they chose it accordingly. They will also tell other people that it's fast and requires care.

I quite agree that the buyers of these cars will be au fait with their capabilities. IF I was to buy one, I'd immediately look for some deserted place I could explore what it does at least once. It's the scenario of someone, usually family, who borrows it, and despite being told it's powerful and to be careful, doesn't listen or appreciate what its potential is.

[robinessex]

GT9 said:

SDK said:

So a rich person buying a powerful ICE supercar is fine and will not crash it.
But a rich person buying an EV will crash it

The desperation to find flaws in the 'EVil masterplan' is getting a bit tragic now.

This is the second thread this year started by someone claiming electric acceleration is very dangerous.

Sorry Rob

As I've said, I've enjoyed 1g acceleration, if you're prepared, it's ok, but if it hits you when you're not, big oops!I Don't know the power it had, but an Ultima with a 7ltr tuned V8 up its arse gets pretty near to that. That's what I was told.

[robinessex]

smn159 said:

robinessex said:

GT9 said:

SDK said:

So a rich person buying a powerful ICE supercar is fine and will not crash it.
But a rich person buying an EV will crash it

The desperation to find flaws in the 'EVil masterplan' is getting a bit tragic now.

This is the second thread this year started by someone claiming electric acceleration is very dangerous.

Sorry Rob

As I've said, I've enjoyed 1g acceleration, if you're prepared, it's ok, but if it hits you when you're not, big oops!I Don't know the power it had, but an Ultima with a 7ltr tuned V8 up its arse gets pretty near to that. That's what I was told.

You think that road cars should be limited in some way?

What power level is acceptable to you?

Assuming we're talking about cars for the average punter, who just wants point-to-point mobility, guess the norm before EVs came along was between 100-200bhp. Didn't hear any complaints about that. Cars of a sporting nature, it's always been an HP race, so carry on guys.

[robinessex]

SpeckledJim said:

robinessex said:

smn159 said:

robinessex said:

GT9 said:

SDK said:

So a rich person buying a powerful ICE supercar is fine and will not crash it.
But a rich person buying an EV will crash it

The desperation to find flaws in the 'EVil masterplan' is getting a bit tragic now.

This is the second thread this year started by someone claiming electric acceleration is very dangerous.

Sorry Rob

As I've said, I've enjoyed 1g acceleration, if you're prepared, it's ok, but if it hits you when you're not, big oops!I Don't know the power it had, but an Ultima with a 7ltr tuned V8 up its arse gets pretty near to that. That's what I was told.

You think that road cars should be limited in some way?

What power level is acceptable to you?

Assuming we're talking about cars for the average punter, who just wants point-to-point mobility, guess the norm before EVs came along was between 100-200bhp. Didn't hear any complaints about that. Cars of a sporting nature, it's always been an HP race, so carry on guys.

Is an M5 a ‘car of a sporting nature’?

How about an X5M?

Probaly

[robinessex]

smn159 said:

How do you decide who does get to drive them? Is an 'average punter' who saves up and buys one OK? At what point does he or she qualify?

By average, I'm referring to those who have no intrinsic interest in cars, and treat them as another commodity purchase, just like a washing machine. It has been mooted in the past that graded driving licenses been introduced, but a bit too late for that now, the horse has bolted.

[robinessex]

SWoll said:

Dave Hedgehog said:

ChocolateFrog said:

RizzoTheRat said:

I suspect the number of people who can pop in to to a Tesla showroom and buy a £150,000 car may be lower than you think

But a Model 3 performance is easily accessible and still pretty quick, not that I agree with the sentiment at all.

up to 100 not a lot in it between a M3P and a lambo

https://www.youtube.com/watch?v=z-ue1ZzaWgM

A standard Aventador takes 11.2 seconds to cover the 1/4 mile, the Model 3 Performance 11.5. Having owned the latter "pretty quick" is a serious understatement.

I will add though that it was an incredibly easy car to drive slowly if you've got any control over your right foot. I can't say the same about any number of lower performance ICE cars I've had over the years.

Neighbour has just acquired one of those, he's promised a ride in it. Admits he hasn't got his head around how bloody quick it is. Confesses to giving the right foot a good push with the wife onboard, his ears are still recovering from the scream she let out.

[robinessex]

GT9 said:

plfrench said:

There's something quite incredible about how EVs can get the power down. It's clearly as a result of the constant torque that GT9 explained earlier, but it is quite spooky.

Just been out for a spin in my wife's new Cupra Born she got yesterday. It's only 204ps, but the way it gets the power down instantly and without a hint of wheelspin on a wet road is bizarre when you've been used to ICE. My E350d is quicker on paper, but it would not be able to get the power down to accelerate at anywhere near the same rate as the born below 40mph. Witchcraft

I extracted this plot some time ago, i think the EV is actually the Born, I can't remember for sure.
The ICE is probably a Golf GTI.
The chart shows what you are experiencing, which is essentially the addition of kinetic energy in the most efficient way possible.

Just what you'd expect with a feedback control system. Just the maximum amount of power all the time, something no human could achieve. Now you know why F1 wants to keep such away from the cars, otherwise, they'd just circulate with driver right foot in fully down mode all the time.

[robinessex]

TheDeuce said:

robinessex said:

By average, I'm referring to those who have no intrinsic interest in cars, and treat them as another commodity purchase, just like a washing machine. It has been mooted in the past that graded driving licenses been introduced, but a bit too late for that now, the horse has bolted.

Those people aren't going to buy an EV with 1000+hp though

In anycase, whatever your fears, the reality is they're not actually leading to more incidents/crashes in the real world. EV insurance costs have been reducing over the years relative to ICE as the underwriters have gained more data. Many EV's are now cheaper in terms of insurance than their ICE equivalents - probably because of the supreme levels of traction they can deliver and maintain making them slightly safer in some situations.

It strikes me as odd that you should be worried about a something that has already been proven to not be the case.

A look at the accident statistics of AXA Switzerland shows that drivers of electric cars cause 50 percent more collisions with damage to their own vehicles than those of conventional combustion engines,” the insurance giant said in a German-language statement titled, ominously, “AXA Crash Tests 2022 — More collisions and new risks from e-cars.”

The company attributed the higher damage from crashes to what it called “the overtapping effect” that causes electric cars to accelerate far faster than their conventional counterparts using the same amount of force on the acceleration pedal. The “overtapping effect” is “likely to be the reason for the increased claims frequency for high-performance electric cars,” the company added.

“Most electric cars, especially the powerful ones, have a very high torque, which is immediately noticeable when you tap the power pedal. This can result in unwanted, jerky acceleration, which the driver can no longer control,” said Michael Pfäffli, HEAD OF ACCIDENT RESEARCH at AXA Switzerland.

[robinessex]

PastelNata said:

It's true that a 1000bhp saloon (EV or ICE) is potentially dangerous when driven by someone who decides to use that much power and doesn't have the skillset.

I can also see where the OP is coming from in terms of a Lambo etc being 'obviously' fast and demanding of respect where a supercar quick saloon might catch an unwitting driver unawares if they haven't paid too much attention to what it actually is they are driving. But then one would hope anyone buying a 1000bhp vehicle would realise what that is and it doesn't need to be 1000bhp to be too much...EV or ICE.

I would argue that most cars on roads today have more power and speed potential than their drivers have skill to control in any emergency. The driving exam only tests the ability to understand the basic rules of the road and driving ability and doesn't test for any speed over the legal limits - nor does it test for any kind of emergency.

Professional drivers still crash. The OP might fancy himself as being above Mr Average in the driving skill stakes - might also just be in his own mind - as he hoons about in his 400bhp ICE car because 'speed matters' innit? Perhaps this is more a nightmare the OP has being overtaken by "Sharon" in her Tesla and not liking it. Not one bit.

Having qualified as a driving instructor with BSM, I'm happy my driving is better than average. I'm not averse to making progress (safely) when the opportunity arises. It never ceases to make me laugh at those who make comments on assumptions they've made.

[robinessex]

Undercover McNoName said:

robinessex said:

Having qualified as a driving instructor with BSM, I'm happy my driving is better than average. I'm not averse to making progress (safely) when the opportunity arises. It never ceases to make me laugh at those who make comments on assumptions they've made.

Speaking of assumptions, what was it about “Sharons” in powerful cars?

Edited by Undercover McNoName on Friday 17th March 19:30

Check you facts. "Sharon" name was invented by another. I just commented on a female driver who didn't realize her 4-wheel drive car only has the same brakes as other cars.

[robinessex]

smn159 said:

robinessex said:

Having qualified as a driving instructor with BSM, I'm happy my driving is better than average.

They teach high speed car handling skills now?

Cool

They do offer more advanced levels if you want. My driving instructor was ex Police pursuit driver actually. In my early driving days, Essex police were offering a part-time 6-week driving course at the now defunct driving base that was located in Springfield, Chelmsford. Great fun, learned a lot, it was a pity that legislation only allowed Police officers to exceed speed limits during the course. Which, of course, I didn't!!!!!!!!! There were also a few disused WW2 airfields around in those days, myself and mates wore a few tyres out playing around on those.

[robinessex]

smn159 said:

robinessex said:

Check you facts. "Sharon" name was invented by another. I just commented on a female driver who didn't realize her 4-wheel drive car only has the same brakes as other cars.

Except it's in your first post on page 1

I stand corrected. Apologies. !! PS I don't actually know any Sharons

[robinessex]

Pixelpeep Electric said:

inexperienced people can crash high powered cars.

Shocker!

Not if they're driving an EV apparently

[robinessex]

As it's been said before, with a powerful car, you arrive at your accident quicker !!!!