Electric cars

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Jdsk
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Re: Electric cars

Post by Jdsk »

Mick F wrote: 9 Dec 2021, 3:52pm
[XAP]Bob wrote: 9 Dec 2021, 9:49am What qualifications do you think you need?
Try getting a job as a "jobbing mechanic" working on an EV.
The batteries are ~450V charged at the moment, so whilst it's "low" voltage in electrical legislation terms they do, as you say, pack a punch - my battery will put out 100kW, which is ~220A, for quite some time.
Hence the danger.
Most people invest in a good pair of insulating gloves when they work on the high voltage side of an EV (as distinct from the low voltage, 12V, side).
A car's 12v battery is chicken feed.
450v isn't high voltage, it's the current regulation that is the danger. I suspect that a traction battery will chuck out 500 or 600 amps without blinking an eyelid.
Insulating gloves is a good idea, but you need an insulated floor and insulated shoes too. You cannot risk anything.
Which setting are you considering... DIY, routine servicing, major component failure, swapping batteries, end of life... ?

There are about 300,000 battery-only EVs, 300,000 PHEVs and 700,000 HEVs in the UK at the moment. There aren't many that are very old yet but most of the tasks that will ever be done will have been done by now.

How many electrical adverse incidents have there been in any of those settings?

Jonathan

Screenshot 2021-12-09 at 17.34.33.png
https://www.rac.co.uk/drive/electric-ca ... -electric/
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[XAP]Bob
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Re: Electric cars

Post by [XAP]Bob »

Mick F wrote: 9 Dec 2021, 3:52pm
[XAP]Bob wrote: 9 Dec 2021, 9:49am What qualifications do you think you need?
Try getting a job as a "jobbing mechanic" working on an EV.
The batteries are ~450V charged at the moment, so whilst it's "low" voltage in electrical legislation terms they do, as you say, pack a punch - my battery will put out 100kW, which is ~220A, for quite some time.
Hence the danger.
Most people invest in a good pair of insulating gloves when they work on the high voltage side of an EV (as distinct from the low voltage, 12V, side).
A car's 12v battery is chicken feed.
450v isn't high voltage, it's the current regulation that is the danger. I suspect that a traction battery will chuck out 500 or 600 amps without blinking an eyelid.
Insulating gloves is a good idea, but you need an insulated floor and insulated shoes too. You cannot risk anything.
I have no interest in becoming a jobbing mechanic on anything - what qualifications do you think are needed? What qualifications are needed to be a jobbing mechanic of an ICE vehicle?

450V is high in terms of car voltages - but yes, the current regulation is fun. Particularly since DC chargers are basically hooked directly to the BMS. shorting a traction battery would be bad - don't do it. Mind you a 12V battery will put out 300+A for tens of seconds...

Obviously gloves aren't the only precautions taken, but they are sufficient - when combined with the processes designed to make it safe.
Last edited by [XAP]Bob on 9 Dec 2021, 10:17pm, edited 1 time in total.
A shortcut has to be a challenge, otherwise it would just be the way. No situation is so dire that panic cannot make it worse.
There are two kinds of people in this world: those can extrapolate from incomplete data.
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[XAP]Bob
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Re: Electric cars

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francovendee wrote: 9 Dec 2021, 5:07pm Factoring in the cost of buidling any new car EV or ICE, if you continue to run a ICE already on the road then the carbon footprint would be less.
I'm sure I'm missing something here?
Depends...

It depends what happens to the existing ICE vehicle.
If you're stupid (like the uK government) and scrap relatively new vehicles for an EV discount then absolutely.

But that's not what happens - when someone changes vehicle that vehicle is sold to someone less well off, and they may well sell their previous vehicle to someone less well off.... until we get to the banger which was written off through lack of tyre tread.

So the car you're taking off the road is oldest, least maintained, most polluting vehicle - not that one you "obviously" swapped out.

But in general the "reduce, reuse" sections of the recycling creed do get forgotten.
A shortcut has to be a challenge, otherwise it would just be the way. No situation is so dire that panic cannot make it worse.
There are two kinds of people in this world: those can extrapolate from incomplete data.
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Mick F
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Re: Electric cars

Post by Mick F »

[XAP]Bob wrote: 9 Dec 2021, 10:12pm I have no interest in becoming a jobbing mechanic on anything - what qualifications do you think are needed? What qualifications are needed to be a jobbing mechanic of an ICE vehicle?
No qualifications necessary for fixing an ICE car, just the knowledge on how it works and access to tools etc.
As for an EV, we have a Toyota Hybrid, and we wouldn't/couldn't get it serviced or fixed at a non-certificated garage.

No doubt fixing the engine would be ok, and doing fluids and oil changes etc, but that's where it stops.

All this is notwithstanding running gear and brakes which tent to be the same on all cars.
Mick F. Cornwall
Jdsk
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Re: Electric cars

Post by Jdsk »

Mick F wrote: 10 Dec 2021, 8:48am
[XAP]Bob wrote: 9 Dec 2021, 10:12pm I have no interest in becoming a jobbing mechanic on anything - what qualifications do you think are needed? What qualifications are needed to be a jobbing mechanic of an ICE vehicle?
No qualifications necessary for fixing an ICE car, just the knowledge on how it works and access to tools etc.
As for an EV, we have a Toyota Hybrid, and we wouldn't/couldn't get it serviced or fixed at a non-certificated garage.
Certificated? Or approved by the manufacturer? Opening up of that market is exactly what the EU has been trying achieve, as upthread.

Jonathan
Jdsk
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Re: Electric cars

Post by Jdsk »

Mick F wrote: 10 Dec 2021, 8:48amAll this is notwithstanding running gear and brakes which tent to be the same on all cars.
The transmission is very different in battery-only EVs. No mechanical clutch and in the vast majority no gear changing. (See previous discussion of the extraordinarily complex transmission in your Toyota hybrid.)

There are no scheduled engine oil changes.

The cooling systems are either nonexistent or much simpler.

The brakes have to slow a more massive vehicle, but regenerative braking decreases the wear on the frictional system. AFAICT the net effect is less wear in practice. (Any data out there, anyone?)

That's several service categories where EVs are going to require much less. In addition to nonexistent components being unable to fail.

Jonathan
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[XAP]Bob
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Re: Electric cars

Post by [XAP]Bob »

Occasionally so little wear that the discs need replacing through corrosion, not use
A shortcut has to be a challenge, otherwise it would just be the way. No situation is so dire that panic cannot make it worse.
There are two kinds of people in this world: those can extrapolate from incomplete data.
Jules59
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Re: Electric cars

Post by Jules59 »

If hydrogen ICE vehicles becomes a reality for everyday motoring as opposed to fuel cells I wonder if the ICE could may be made much simpler as there would be no need for the complex emission control systems (exhaust gas recirculation , particulate filters and catalyst convertors). Maybe a stop gap until a more sustainable solution is found.
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[XAP]Bob
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Re: Electric cars

Post by [XAP]Bob »

If you're carrying hydrogen then you go fuel cell - nearly double the range.
A shortcut has to be a challenge, otherwise it would just be the way. No situation is so dire that panic cannot make it worse.
There are two kinds of people in this world: those can extrapolate from incomplete data.
francovendee
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Re: Electric cars

Post by francovendee »

[XAP]Bob wrote: 9 Dec 2021, 10:16pm
francovendee wrote: 9 Dec 2021, 5:07pm Factoring in the cost of buidling any new car EV or ICE, if you continue to run a ICE already on the road then the carbon footprint would be less.
I'm sure I'm missing something here?
Depends...

It depends what happens to the existing ICE vehicle.
If you're stupid (like the uK government) and scrap relatively new vehicles for an EV discount then absolutely.

But that's not what happens - when someone changes vehicle that vehicle is sold to someone less well off, and they may well sell their previous vehicle to someone less well off.... until we get to the banger which was written off through lack of tyre tread.

So the car you're taking off the road is oldest, least maintained, most polluting vehicle - not that one you "obviously" swapped out.

But in general the "reduce, reuse" sections of the recycling creed do get forgotten.
If contemplating buying a brand new car then the choice of EV or ICE will be.
How you feel about range.
Charging points now, not in some uncertain future time.
If the running cost will justify any savings.
The carbon footprint to make either will not be vastly different.
In time, unless another form of power turns up, EVs will gradually have replaced the older ICE cars.
I think many old car users will try to keep their's running for as long as possible until they are un-repairable or fuel becomes megga expensive.
By this time it's to be hoped the charging infrastructure is in place and pitfalls of old EVs are well known.
Jdsk
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Re: Electric cars

Post by Jdsk »

Jules59 wrote: 10 Dec 2021, 9:28am If hydrogen ICE vehicles becomes a reality for everyday motoring as opposed to fuel cells I wonder if the ICE could may be made much simpler as there would be no need for the complex emission control systems (exhaust gas recirculation , particulate filters and catalyst convertors). Maybe a stop gap until a more sustainable solution is found.
[XAP]Bob wrote: 10 Dec 2021, 11:48am If you're carrying hydrogen then you go fuel cell - nearly double the range.
I don't see the attraction of hydrogen ICE for things like cars. It might be different in other niches.

1 Energy chain
There's an enormous loss of energy in generation and transmission for anything based on hydrogen. Possibly something like 60%.

2 Infrastructure
Putting in EV chargers isn't easy but is going OK-ish. Putting in hydrogen is more complex and expensive at every part of the process.

3 Technology
Hydrogen ICE needs a whole of things that battery-only doesn't: reciprocating to circular motion, clutch, gearbox, cooling, starting, ignition, exhaust. And it does need emission control because of the formation of nitrogen oxides in the combustion, and that's probably going to mean catalytic converters. And it won't support regenerative braking.

Jonathan
Last edited by Jdsk on 10 Dec 2021, 5:55pm, edited 2 times in total.
Jdsk
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Re: Electric cars

Post by Jdsk »

Jdsk wrote: 10 Dec 2021, 9:01am The brakes have to slow a more massive vehicle, but regenerative braking decreases the wear on the frictional system. AFAICT the net effect is less wear in practice. (Any data out there, anyone?)
[XAP]Bob wrote: 10 Dec 2021, 9:07am Occasionally so little wear that the discs need replacing through corrosion, not use
Thanks.

I've also read reports of fluid changes being neglected because pads didn't need to be replaced.

Jonathan
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[XAP]Bob
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Re: Electric cars

Post by [XAP]Bob »

Yep - I know of people who can happily do a several hundred mile journey and the only time the brakes get used is when they pull the handbrake on...
A shortcut has to be a challenge, otherwise it would just be the way. No situation is so dire that panic cannot make it worse.
There are two kinds of people in this world: those can extrapolate from incomplete data.
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Mick F
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Re: Electric cars

Post by Mick F »

Slightly off topic maybe?
People who fix cars, smell of cars eh?
What about people working in "environments"?

Back in the olden days, our daughters and Mrs Mick F would meet my ship when we came back from sea/deployment etc.
The girls would say, "Daddy! You smell of Ship!"
I would reply, "You smell of School!"

At the Rising Sun Inn earlier this evening, Gunnislake Garage staff were there having a drink or three.
They smelled of "garage" and oil and engines. All of them - half a dozen? - were manky and in work clothes.
I know all of them. :D

https://www.gunnislakegarage.co.uk
Mick F. Cornwall
pwa
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Re: Electric cars

Post by pwa »

Jdsk wrote: 10 Dec 2021, 4:51pm
Jdsk wrote: 10 Dec 2021, 9:01am The brakes have to slow a more massive vehicle, but regenerative braking decreases the wear on the frictional system. AFAICT the net effect is less wear in practice. (Any data out there, anyone?)
[XAP]Bob wrote: 10 Dec 2021, 9:07am Occasionally so little wear that the discs need replacing through corrosion, not use
Thanks.

I've also read reports of fluid changes being neglected because pads didn't need to be replaced.

Jonathan
I try to make a habit of doing a little bit of heavy braking (with no vehicles behind) once in a while, just to scrub the discs. I don't know if it does any good but it feels like the right thing to do. Apart from that I use the brakes as little as possible, just as I do cycling.
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