UK switching to electric vehicles discussion

[Bald Rick]

I suspect that the thing that will cause a lot of modern cars will be from glitches in the software, sensors and electronics. Some of these will just be annoying, but some will be an MOT failure.

I‘m with you and @Bletchleyite on this. I don‘t change cars ery often, but pretty much every problem I’ve had with my last 3 cars going back 22 years has been the electronics, normally a sesnor sensing somethign thst isnt there.

My personal dislike is electronic handbrakes, but it's almost impossible to avoid them now. There is absolutely nothing wrong with a traditional cable-operated one, and it's better in some ways, e.g. being able to use it to assist in pulling off smoothly without rolling back, with no need for even more electronic junk e.g. "hill start assist" to mitigate its absence.

Now I disagree with this. I’ve had electric handbrakes for 17 years now and much prefer them. There‘s no hill start function or anything like that, it just automatically comes on when I stop and releases when I start moving. Never, ever had a rollback.

What I did have, though, with my traditionally handbraked cars is the cable stretching suddenly to the extent that it wouldn‘t hold the car on a steep hill. That happened twice on two different cars.

 

[Noddy]

Talking of brakes, I’m wondering how much longer it’ll be before manufacturers come up with a system that will allow mechanical brakes to be partially or even completely removed from EVs.

 

[trebor79]

Talking of brakes, I’m wondering how much longer it’ll be before manufacturers come up with a system that will allow mechanical brakes to be partially or even completely removed from EVs.

Never.
Regen braking isn't effective at slow speeds, so the friction brakes bleed in to make a complete stop. That could be overcome with a loss of efficiency, but...
What if the inverter fails, or some other protection kicks in to trip the system? What if the battery is nearly full and you're going down a hill or need to stop suddenly?
What if you need to slow down more quickly than the battery can accept charge?

There's are possible technical solutions to these scenarios. But they all add complexity and cost and don't provide any energy saving benefit over dissipating that excess energy as heat from simple friction brakes.

 

[Bald Rick]

Talking of brakes, I’m wondering how much longer it’ll be before manufacturers come up with a system that will allow mechanical brakes to be partially or even completely removed from EVs.

We’ve had regen braking on the railway for at least 70 years - if there was a way of doing away with friction brakes as back up I’m fairly sure we‘d have found it by now.

 

[Noddy]

Never.
Regen braking isn't effective at slow speeds, so the friction brakes bleed in to make a complete stop. That could be overcome with a loss of efficiency, but...
What if the inverter fails, or some other protection kicks in to trip the system? What if the battery is nearly full and you're going down a hill or need to stop suddenly?
What if you need to slow down more quickly than the battery can accept charge?

There's are possible technical solutions to these scenarios. But they all add complexity and cost and don't provide any energy saving benefit over dissipating that excess energy as heat from simple friction brakes.

Never say never! Formula E have removed rear brakes, so how much longer before we see this from manufacturers (note I did say partially).

 

[miklcct]

at work, at a supermarket / shopping centre while you do your shopping, at the station, at a bespoke charging station, or wherever you park it near home with a charger (which I accept won’t be in place yet!). If you drive an average mileage, and an average EV, you’ll be needing to fully charge every fortnight, or for an hour a day on a slow charger / 10 minutes on a typical quick charger.

last week I drove past an EV charging station in Manchester - with a Greggs on site - and it was reasonably patronised. Park up, plug in, get a coffee, drink coffee, check emails, unplug having gained 100miles range. Definitely the future.

The last time (and my only time) I used an EV was hiring one. The train line was blown out by the storm the day before so I decided to hire a car. The stated range from the manufacturer could get me from Eastleigh to London but when I pick up the car, which was fully charged, had only about 62 miles of range.

I planned to break my journey at Guildford. By the time I reached Guildford there were only 10 miles left, however the parking at my destination didn't have any electric car charging facilities, I then tried finding one nearby from a map but it was out of service, and eventually only after a few tries I could find a charger on street.

After I had done my stuff in Guildford, I went back to pick up the car. However to my surprise it wasn't charged at all! The one I connected didn't work in the few hours I left the car! With just a few miles left I failed to reach London on the day and missed the event.

 

[AM9]

Never say never! Formula E have removed rear brakes, so how much longer before we see this from manufacturers (note I did say partially).

But formula E cars aren't required to be parked on gradients.

 

[DustyBin]

But formula E cars aren't required to be parked on gradients.

If you’re alluding to the need for a hand/parking brake on road cars, it does’t need to be applied at the rear.

 

[AM9]

If you’re alluding to the need for a hand/parking brake on road cars, it does’t need to be applied at the rear.

Not really, but all wheel braking independent of traction on road going vehicles with a parking brake is unlikely to be dropped on safety grounds anyway. Any attempt to restrain a car parked on an incline by electromagnetic means would put an unacceptable drain on the battery, which would eventually release the brake!

 

[trebor79]

Never say never! Formula E have removed rear brakes, so how much longer before we see this from manufacturers (note I did say partially).

Bit different. Controlled environment, skilled drivers wearing helmets etc. What do you think will happen to the average driver with their family in the car if, when driving on a wet day all breaking force is suddenly transferred to the front wheels?

 

[Noddy]

Bit different. Controlled environment, skilled drivers wearing helmets etc. What do you think will happen to the average driver with their family in the car if, when driving on a wet day all breaking force is suddenly transferred to the front wheels?

Oh I don’t doubt that and they are a safety critical system so everyone (manufacturers, regulators, etc) is likely to be extremely conservative. How often does say the inverter or electric motor fail in transit?

 

[AM9]

Oh I don’t doubt that and they are a safety critical system so everyone (manufacturers, regulators, etc) is likely to be extremely conservative. How often does say the inverter or electric motor fail in transit?

Probably more often than even a cable operated parking brake, which when multiplied by the number of road-going vehicles is a significant risk.

== Doublepost prevention - post automatically merged: 11 Nov 2023 ==

Oh I don’t doubt that and they are a safety critical system so everyone (manufacturers, regulators, etc) is likely to be extremely conservative. How often does say the inverter or electric motor fail in transit?

Probably more often than an averagely maintained cable operated paring brake, which is effectively fail-safe, (as in once applied, unlikely to fail until released). Anything relying on the traction or auxiliary battery to restrain the vehicle would eventually fail through lack of power.

 

[Bletchleyite]

Bit different. Controlled environment, skilled drivers wearing helmets etc. What do you think will happen to the average driver with their family in the car if, when driving on a wet day all breaking force is suddenly transferred to the front wheels?

Nothing, because in older cars (typically discs front, drums back) most force is at the front anyway.

Don't confuse it with a bicycle where jamming on the front might throw you over the bars, cars are too heavy for that.

 

[jon0844]

The Telegraph is now blaming EVs for not only being too heavy for car parks but being responsible for the rise in potholes.

 

[DustyBin]

Not really, but all wheel braking independent of traction on road going vehicles with a parking brake is unlikely to be dropped on safety grounds anyway. Any attempt to restrain a car parked on an incline by electromagnetic means would put an unacceptable drain on the battery, which would eventually release the brake!

I agree; it’s probably a moot point for the reasons stated. I was responding on the basis of what @Noddy pointed out in regard to Formula E though.

 

[trebor79]

Oh I don’t doubt that and they are a safety critical system so everyone (manufacturers, regulators, etc) is likely to be extremely conservative. How often does say the inverter or electric motor fail in transit?

Not very often. But there are times regenerative braking is unavailable or degraded for other reasons, such as the battery being at a high state of charge, battery temperature etc.

 

[Bantamzen]

The Telegraph is now blaming EVs for not only being too heavy for car parks but being responsible for the rise in potholes.

Are EVs heavier, I honestly don't know? One thing I really don't like about them is how quiet they are for walkers on country roads. At least a couple of times I've been caught out with EVs coming up behind me on twisty roads without me realising until the last moment. At least with petrol or diesel engines I can hear them from a distance in the countryside, but EVs you can only hear if the road surface is noisy.

 

[AndrewE]

Are EVs heavier, I honestly don't know? One thing I really don't like about them is how quiet they are for walkers on country roads. At least a couple of times I've been caught out with EVs coming up behind me on twisty roads without me realising until the last moment. At least with petrol or diesel engines I can hear them from a distance in the countryside, but EVs you can only hear if the road surface is noisy.

That's a benefit overall, but you really would hope that the drivers would have the courtesy to give you a pip on the horn to warn of their appproach.

 

[GLC]

Are EVs heavier, I honestly don't know? One thing I really don't like about them is how quiet they are for walkers on country roads. At least a couple of times I've been caught out with EVs coming up behind me on twisty roads without me realising until the last moment. At least with petrol or diesel engines I can hear them from a distance in the countryside, but EVs you can only hear if the road surface is noisy.

Modern cars are generally heavier anyway, and batteries alone are indeed heavier than an equivalent ICE powertrain. The real problem with EV weight is that, thanks to increasingly efficient regen, manufacturers have less incentive to engineer weight out of an EV (which takes time and therefore costs money), when the difference it makes in range is less pronounced than you might think. Regen works on Energy = mass * gravity * height and so even if an EV is a 2.5 ton SUV, that takes a huge amount of energy to get moving, all that extra weight does is increase the energy you can and will recover. Now, that’s not to say that weight doesn’t have negative impacts on road wear, tyre wear, handling, pedestrian safety etc etc, but the upfront impact of weight in an EV is unfortunately not a big issue. It’s for this reason that BMW abandoned building their EVs with carbon fibre tubs(The i3 and i8). The expense of the tub was never justified by the weight savings and range benefits it gave.

As for noise I completely agree. My EV is old enough to not have a low speed noise generator, so it really is completely silent at low speeds, and in a city I’ve often had people walk out onto the road not knowing I was there(understandably!)

 

[Roast Veg]

People need to stop buying SUVs. There simply shouldn't be a market for them.

 

[DustyBin]

Are EVs heavier, I honestly don't know? One thing I really don't like about them is how quiet they are for walkers on country roads. At least a couple of times I've been caught out with EVs coming up behind me on twisty roads without me realising until the last moment. At least with petrol or diesel engines I can hear them from a distance in the countryside, but EVs you can only hear if the road surface is noisy.

They are. I test drove a BMW i4 recently, and noted that it was circa half a tonne heavier than my previous 5 Series.

It’s a stretch though to claim that the additional weight causes increased road wear. Half a tonne here and there is inconsequential really.

 

[AndrewE]

It’s a stretch though to claim that the additional weight causes increased road wear. Half a tonne here and there is inconsequential really.

It's not inconsequential. I'm sure that road "wear" is proportional to quite a big power of the weight applied, like 4th or 5th, so it's a lot more... first hit on Google says

We've known this since the 1950s when (maths alert) it was calculated that the change in damage to the road surface is proportional to the difference in axle weight to the fourth power. A two-tonne SUV would therefore do 16 times more damage than a one-tonne car.

 

[DelW]

It's not inconsequential. I'm sure that road "wear" is proportional to quite a big power of the weight applied, like 4th or 5th, so it's a lot more... first hit on Google says

Fourth power has indeed been the accepted value at least since I was at university in the 1970s. While that does mean heavier cars do more damage than light ones, it also means that both are trivial in comparison with large vans and LGVs, and within the rounding errors for the calculations of HGVs which run at up to 12t per axle.

 

[The Ham]

The Telegraph is now blaming EVs for not only being too heavy for car parks but being responsible for the rise in potholes.

Whilst EV's are heavier, there's also a significant rise in delivery vans - which are much heavier.

Of course the poor maintenance (due to lack of funds from central government) can't be the issue can it‽

Fourth power has indeed been the accepted value at least since I was at university in the 1970s. While that does mean heavier cars do more damage than light ones, it also means that both are trivial in comparison with large vans and LGVs, and within the rounding errors for the calculations of HGVs which run at up to 12t per axle.

When working out the design life of a road you don't even count anything other than lorries. Obviously the need to replace the road surface and other maintenance is impacted by car and van volumes.

 

[DustyBin]

It's not inconsequential. I'm sure that road "wear" is proportional to quite a big power of the weight applied, like 4th or 5th, so it's a lot more... first hit on Google says

Perhaps “trivial” would have been a better word as per @DelW. In reality, the roads aren’t breaking up as a result of (some) cars gaining a few hundred kilograms.

 

[Harpers Tate]

One thing I really don't like about them is how quiet they are for walkers on country roads

Interesting comment, that I have seen before elsewhere. I spent a little time at the side of a very average, level road in a 30mph area recently to consider that point (subjectively, only). And my observation is this: as long as the approaching ICE is a relatively small petrol car and is not under stress (eg accelerating hard) and is properly maintained (so, not, for example, some boy racer with a blown exhaust) then in my experience one can not (or at best, hardly) hear the engine above the tyre noise until AFTER the vehicle has passed. In my experience, they make no more noise than an EV whilst behind you. EVs all (I think) have a virtual spaceship-like noise that sounds under 15mph and that is on by default whenever the car is started - although in some (or all?) it can be disabled by the driver after starting.

 

[Bantamzen]

Interesting comment, that I have seen before elsewhere. I spent a little time at the side of a very average, level road in a 30mph area recently to consider that point (subjectively, only). And my observation is this: as long as the approaching ICE is a relatively small petrol car and is not under stress (eg accelerating hard) and is properly maintained (so, not, for example, some boy racer with a blown exhaust) then in my experience one can not (or at best, hardly) hear the engine above the tyre noise until AFTER the vehicle has passed. In my experience, they make no more noise than an EV whilst behind you. EVs all (I think) have a virtual spaceship-like noise that sounds under 15mph and that is on by default whenever the car is started - although in some (or all?) it can be disabled by the driver after starting.

I can honestly say that I can usually hear the sound of an ICE approaching when out and about in the countryside, I specifically listen out for the noise because a lot of the lanes I walk are very narrow, often with high hedgerows. But on the few occasions I've seen EVs, they are much harder to hear especially where the roads are curving and with hedgerows. On one occasion on a lane I know very well two Teslas came up behind me and honestly I had no idea until they were practically on top of me. Thankfully they were driving carefully, otherwise it could have been nasty.

 

[DelW]

EVs all (I think) have a virtual spaceship-like noise that sounds under 15mph and that is on by default whenever the car is started - although in some (or all?) it can be disabled by the driver after starting.

I think this became compulsory two or three years ago. When I specced my current PHEV in early 2020 it was still an option (which I chose). It can be disabled for the current journey only, but I've never done so as it's barely audible from inside the car.

 

[trebor79]

Interesting comment, that I have seen before elsewhere. I spent a little time at the side of a very average, level road in a 30mph area recently to consider that point (subjectively, only). And my observation is this: as long as the approaching ICE is a relatively small petrol car and is not under stress (eg accelerating hard) and is properly maintained (so, not, for example, some boy racer with a blown exhaust) then in my experience one can not (or at best, hardly) hear the engine above the tyre noise until AFTER the vehicle has passed. In my experience, they make no more noise than an EV whilst behind you. EVs all (I think) have a virtual spaceship-like noise that sounds under 15mph and that is on by default whenever the car is started - although in some (or all?) it can be disabled by the driver after starting.

All EVs sold since some date last year must have an audible warning below 28mph. Prior to that it could either be turned off by the driver, or not provided at all. Our 21 plate Tesla makes no noise at all, but our Kia Niro EV makes a spaceship sound in drive and repeated bonging in reverse.

 

[greyman42]

People need to stop buying SUVs. There simply shouldn't be a market for them.

What do you mean by there should not be a market for them? Markets tend to define themselves.