Dangers of DIY car brake maintenance

[jb]

I think Hydrogen fuel cells will become more dominant eventually, having all these high powered chargers at all households seem a recipe for disaster one way or another.
Its got the potential to store large amounts of unwanted energy from wind farms, its more like filling up a car at a petrol station and hopefully deterioration will be less horrific plus it has all the advantages of electric drive.

And the government will be able to tax it so everyone's happy.

[Jdsk]

Hydrogen has a big part to play in many applications, possibly including energy storage from renewable sources.

But ordinary private cars isn't one of them. The complexity and cost of compression is far too high.

What sort of disaster are you envisaging with home charging of EVs?

Thanks

Jonathan

[Cowsham]

I never understood why it is more efficient to change chemical energy into mechanical/and heat energy and then into electrical energy to charge a battery, ( chemical stored energy into the battery) and then back into mechanical energy to drive the wheels of a hybrid.

It comes from a combination of factors including the weird but familiar operating envelope of piston engines, the many different conditions under which road cars operate, and the ability to incorporate regenerative braking.

If you only think of operating in a single steady state there is no gain of "efficiency".

Jonathan

Is that Jdsk speak for "nor me" ?

Bottom line is hybrids are not as efficient as straight ic -- that's a fact according to Toyota.

[jb]

Mainly the infrastructure, I imagine there will be (is) adequate safety trips for the users but getting a network that will work across rows of terraced houses and flats - doesn't seem practical. Especially if putting a kettle on after a soap is still an issue with the power companies.

Hydrogen production can only get cheaper it doesn't need piping into everyone's house along various quality / ageing lines and fuel cells are getting better.

[Jdsk]

I never understood why it is more efficient to change chemical energy into mechanical/and heat energy and then into electrical energy to charge a battery, ( chemical stored energy into the battery) and then back into mechanical energy to drive the wheels of a hybrid.

It comes from a combination of factors including the weird but familiar operating envelope of piston engines, the many different conditions under which road cars operate, and the ability to incorporate regenerative braking.

If you only think of operating in a single steady state there is no gain of "efficiency".

Is that Jdsk speak for "nor me" ?

Bottom line is hybrids are not as efficient as straight ic -- that's a fact according to Toyota.

Sorry, I worded that badly. By "It comes from... " I meant "The reasons for building and using hybrid vehicles are ... ".

Jonathan

[Jdsk]

I think Hydrogen fuel cells will become more dominant eventually, having all these high powered chargers at all households seem a recipe for disaster one way or another.

What sort of disaster are you envisaging with home charging of EVs?

Hydrogen production can only get cheaper it doesn't need piping into everyone's house along various quality / ageing lines and fuel cells are getting better.

Hydrogen production will get cheaper, or at least relatively less expensive. Fuel cells will improve.

But the problem with using it as a fuel for cars is the enormous compression that is required to get a useful energy storage density. That would demand a vast amount of new infrastructure, and even then the cost of distribution will be high and the efficiency low.

But I don't understand the "disaster" that you foresee from home charging of EVs. The electrical supply is already in place. And many users who don't have suitable space will charge them elsewhere.

Jonathan

[jb]

The supply cable running to my house is cloth bound & must date from the forties along with the rest of the street - designed to supply a toaster a valve radio and a few lightbulbs. whilst disaster might be the wrong word the frequency of power failure has the potential to become an issue IMHO

[Biospace]

Hydraulic motors in cars?

Yes, Louis Renault proposed the idea back in 1908, the Citroën company ran several hydro powered cars over a million km from the 1950s, noise was the problem, since overcome. Agricultural and industrial vehicles are often powered with hydraulic motors - the bigger the load and more difficult the working conditions, the greater their advantage over electric motors. In a car, you lose the weight and complication of gearbox, clutch and driveshafts and gain the potential for high levels of regen fairly easily.

More recently, Bosch trialled a system of hydraulic hybrid in North American refuse trucks and there was a proposal for this little Peugeot, https://www.extremetech.com/extreme/146 ... 80-mpg-car. I haven't heard any more, presumably in large part because of the industry's mass adoption of electric battery cars. EMs are cheap and available off the shelf, they're improving and the advent of a new generation of capacitors should improve regen in stop-start conditions.

I never understood why it is more efficient to change chemical energy into mechanical/and heat energy and then into electrical energy to charge a battery, ( chemical stored energy into the battery) and then back into mechanical energy to drive the wheels of a hybrid.

As I said above the hybrid yaris on the spec sheet from Toyota themselves said 47MPG while the 1.3 petrol ( T spirit ) said 55MPG from memory -- which left me wondering why anyone would buy the hybrid when the 1.3 was faster, a bigger boot space, much less complex and more economical on fuel.

The way I understand it is that a large part of the electrical vehicle revolution is expected to be dependent on renewable and nuclear energy. As you point out, there is an obvious energy flaw in burning fossil fuel - steam turbines - transmission of electricity - battery charging - electric motor for motive power compared with carrying the liquid fuel direct to where it is burned to release energy in an engine to move your vehicle.

Emissions are cleaner when burning fuel in a power station and move city car exhaust pollution to the countryside. If we only switched delivery vehicles and commuters to battery power, it would make a huge difference to urban and suburban air quality. It's important to remember that motor vehicles represent only a part of NOx, particulate and other pollution - shipping, wood and coal burning and air traffic are all but ignored compared with road transport.

The battery electric car can appear more efficient than it really is as the cost of fuelling it (from a domestic supply) is so low compared with a petrol or diesel equivalent. Two reasons - electricity supply is taxed far less than forecourt fuel and included in this cheaper price is the cost of the losses when turning ff into electricity (~50% loss). At the moment, it's a huge monetary saving to drive around in an EV, but the environmental side is markedly less.

Hydrogen burns clean but it needs plenty of energy to make, there are significant costs over and above propane storage and transportation. Either can be made with excess renewable production, either for use in direct home heating, ICEs or fuel cells.

Thoughts:

• The trolley bus was extremely efficient transport
  Relying entirely on electricity for the home and transport looks like many eggs in one basket, it's potentially a lot of extra control over a population
  Battery electric cars have failed once, because they were slow to charge and large batteries for longer distances rather heavy
  A car with a small engine burning gas used as the generator for an EM, with 20kg of batteries would be very efficient
  I expect fuel cells to replace battery EVs

[Cowsham]

Well I've started a new chapter by building an electric bicycle and had my first run out on it today ( will start a new thread for this ) -- I'm going to use it specifically for commuting and shopping if I need my energy later for physical work after the shopping.

I recon I can save the cost of the bike over the summer maybe even what's left of the summer if fuel prices stay high.

As for transport for the masses there needs to be some benefit to make it work. I've always believed this cos people don't generally change behavior out of the goodness of their heart there's always some selfish reason even if the motive is repentance or guilt that in itself is selfish.

My selfish reason is cost of fuel, more exercise ( rather than the days I go in the car cos I'm too tired from the days standard cycle commute ) or the fun of floating along on a magic bicycle or all three on a nice day.

[peetee]

While we are on the subject of hybrid vehicles, I never really understood why diesel-electric lorries never became the norm. Diesel engines are at their best when run at continuous RPM and electric motors are ideal for accelerating from stationary. Both factors lend themselves to the removal of a mechanical gearbox from the Diesel engine and the substitution of a generator that supplies current to electric motors.

[pete75]

Emissions are cleaner when burning fuel in a power station and move city car exhaust pollution to the countryside.

As a countryside dweller I'd prefer it to remain in the city thank you very much. The activities of urban dwellers produce the pollution so it's only right and proper they suffer it's effects.

[Cowsham]

One benefit from fully electric cars if I understand it correctly is, there's an intention to use electric cars as a storage for the grid or at least a personal storage for your personal use. ie the energy produced by turbines or solar panels could be stored in a grid of electric cars ie your electric car while parked. Then the stored energy used to back up the grid.

I know you're thinking what if I need my car and it's supplying the grid. as I understand when we reach a critical level of electric car ownership ie nearly everyone that has a car has an electric car, one car or a large number of cars disconnecting won't influence the grid.

There'll be logistics around it for sure but I think generally the idea is a good one.

[Biospace]

One benefit from fully electric cars if I understand it correctly is, there's an intention to use electric cars as a storage for the grid or at least a personal storage for your personal use. ie the energy produced by turbines or solar panels could be stored in a grid of electric cars ie your electric car while parked. Then the stored energy used to back up the grid.

I know you're thinking what if I need my car and it's supplying the grid. as I understand when we reach a critical level of electric car ownership ie nearly everyone that has a car has an electric car, one car or a large number of cars disconnecting won't influence the grid.

There'll be logistics around it for sure but I think generally the idea is a good one.

It should reduce the number of power stations needed, although it would be a folly to encourage those who don't need them to have a third or more of a tonne battery pack extra for nothing more than to smooth the grid demand.

Theoretically it would be possible to design removable battery packs for easy replacement on a long journey but I don't see much evidence of this happening. Perhaps it would encourage theft?

Are motorhomes and caravanners going to become extinct, or will they hop 100 miles or less at a time? Or will hybrids with larger engines be available for decades?

[Mick F]

How does - or will - an EV supply current to the grid?

At the moment, you connect your EV to a 250vAC socket, and the electronics in the EV convert it to DC at whatever voltage the battery requires.

So, when the battery if full, the EV would need some more electronic devices to reverse the procedure.
This means, that the charging cable will be "live" with 250vAC, just uncoiling it from under the bonnet ....... or wherever.

Have I got this right?

[Jdsk]

One benefit from fully electric cars if I understand it correctly is, there's an intention to use electric cars as a storage for the grid or at least a personal storage for your personal use. ie the energy produced by turbines or solar panels could be stored in a grid of electric cars ie your electric car while parked. Then the stored energy used to back up the grid.

I know you're thinking what if I need my car and it's supplying the grid. as I understand when we reach a critical level of electric car ownership ie nearly everyone that has a car has an electric car, one car or a large number of cars disconnecting won't influence the grid.

There'll be logistics around it for sure but I think generally the idea is a good one.

How does - or will - an EV supply current to the grid?

At the moment, you connect your EV to a 250vAC socket, and the electronics in the EV convert it to DC at whatever voltage the battery requires.

So, when the battery if full, the EV would need some more electronic devices to reverse the procedure.
This means, that the charging cable will be "live" with 250vAC, just uncoiling it from under the bonnet ....... or wherever.

Have I got this right?

It's called vehicle-to-grid:
https://en.wikipedia.org/wiki/Vehicle-to-grid

It isn't widespread yet, but there don't seem to be any showstoppers, and it could provide a useful amount of storage and balancing.

It does demand connection between the vehicle and the grid but that will be the existing charging cable, which doesn't usually require "uncoiling ... from under the bonnet".

Jonathan