Has JCB saved engines?
Discussion
Polite M135 driver said:
I don’t know. I take your point that at steady speed the mass makes minimal/zero difference (I don’t know which, I don’t remember the formula for friction and if mass is in it or not). But cars don’t spend all their time at steady state speed, do they? The clue to this is that you can both get in and out of them without being horribly mutilated and also go places in them.
Although you have made me wonder if trains should never stop at stations but instead pick up passengers with something like those funny mail bag collecting They used to (?) have.
The main problem with mass and efficiency is that the amount of energy you have to throw away whenever you use the friction brakes is proportional to the mass of the car. Although you have made me wonder if trains should never stop at stations but instead pick up passengers with something like those funny mail bag collecting They used to (?) have.
The reason mass is much less of a problem with electric and hybrid cars is that they have the option of not using the friction brakes and instead recovering a good chunk of that energy into the battery.
cidered77 said:
Swanon's Law on Solar is that the price reduces 20% for every doubling of shipped volume. Easily googleable graph shows still very much happening.
I find it extremely hard to believe the volume of R&D money put into batteries won't see improves in storage capacity (other posts here seem to confirm), but my point was the option to go off grid is as much about cost as it is on performance of a home battery + solar, and increased volume in battery production of course will continue to reduce price.
Roll forward 10 years and the number of people drawing the majority of their power from off the grid will be significantly higher than now, which causes all manner of issues on how you fund the grid - which we'll all still need. Tis a tangential point to this whole thread, anyway.
You'd hope so. I have a lot of roof real estate that's crying out for solar, I've barns I could build a battery in. I could go completely off grid and switch over to EVs. It would be a great thing to do. The problem is that it remains hugely expensive and the Grid is just infinitely more efficient, more environmental and cheaper to source electricity from. I find it extremely hard to believe the volume of R&D money put into batteries won't see improves in storage capacity (other posts here seem to confirm), but my point was the option to go off grid is as much about cost as it is on performance of a home battery + solar, and increased volume in battery production of course will continue to reduce price.
Roll forward 10 years and the number of people drawing the majority of their power from off the grid will be significantly higher than now, which causes all manner of issues on how you fund the grid - which we'll all still need. Tis a tangential point to this whole thread, anyway.
Beyond the cost hurdle, not many people have enough roof or domestic storage space for enough solar and batteries to be self sufficient anyway. That's a function of the inefficiency of solar panels and batteries.
The truth is that the electricity that gets wired to our homes is going to be cheaper and greener than almost anything anyone can produce domestically.
Even Musk has given up lying about solar as not even he can get enough people to fall for it.
And most of the conmen in the UK have returned to selling double glazing.
DonkeyApple said:
You'd hope so. I have a lot of roof real estate that's crying out for solar, I've barns I could build a battery in. I could go completely off grid and switch over to EVs. It would be a great thing to do. The problem is that it remains hugely expensive and the Grid is just infinitely more efficient, more environmental and cheaper to source electricity from.
Beyond the cost hurdle, not many people have enough roof or domestic storage space for enough solar and batteries to be self sufficient anyway. That's a function of the inefficiency of solar panels and batteries.
The truth is that the electricity that gets wired to our homes is going to be cheaper and greener than almost anything anyone can produce domestically.
yeah definitely won't work for all - although, if there *is* a material improvement (or these trends continue), then for example it's not impossible to imagine new builds mandated to have solar roof panels, in the same way they're mandated to be properly insulated...Beyond the cost hurdle, not many people have enough roof or domestic storage space for enough solar and batteries to be self sufficient anyway. That's a function of the inefficiency of solar panels and batteries.
The truth is that the electricity that gets wired to our homes is going to be cheaper and greener than almost anything anyone can produce domestically.
I've got 4 large roof surfaces south/south east facing, and a garage loft filled with crap that would be a great candidate- but not everyone in that position. around 2025 when I likely switch to EV for the family bus (got one more iteration to go for me when i replace the current one), then having much cheaper energy generated at home makes a significant difference in running costs over 10-15k miles per year....
thatdude said:
Vintagejock said:
More than likely. Eventually battery powered trucks will surely have to carry more weight in batteries than actual payload. And of course for all the eco warriors, how do you generate the electricity in the first place?
Nuclear fusion, duh. It's only 20 years away from being commercially applicable!
Killboy said:
Residential solar is a non-starter.
Its actually started sorry to let you know https://www.tesla.com/solarroofAPontus said:
Batteries might be 'crap', but they're a damned sight better than the million year old 'tech' ICE cars store their energy in.
Except they're not. The issue is energy density and while undoubtedly an electric motor is superior in many ways (although I'm not _too_ sure on power to weight), still as yet nothing beats hydrocarbons for storing lots of easily refillable energy.
A battery is at _best_ ~200Wh/Kg.
Petrol is 46.4Mj/Kg or about 12777Wh/Kg. Even at ~20% efficiency that's still 12x better than the best battery technology.
Volvolover said:
Killboy said:
Residential solar is a non-starter.
Its actually started sorry to let you know https://www.tesla.com/solarroofTalk about breaking a calculator.
Dave Hedgehog said:
thatdude said:
Vintagejock said:
More than likely. Eventually battery powered trucks will surely have to carry more weight in batteries than actual payload. And of course for all the eco warriors, how do you generate the electricity in the first place?
Nuclear fusion, duh. It's only 20 years away from being commercially applicable!
We've only gone from blacksmiths to Ligo (can measure distance from here to nearest star accurate to less than a human hair) in only a few hundred years after all.....
Killboy said:
Volvolover said:
Killboy said:
Residential solar is a non-starter.
Its actually started sorry to let you know https://www.tesla.com/solarroofTalk about breaking a calculator.
Swanson's Law pasted again... i once saw a graph on some of the major exponential change curves of recent years (semi-conductor performance, growth of digital/online businesses; growth of connected devices - that sort of thing); with past predictions of "experts" plotted alongside them, universally pessimistic as exponential change tends to keep going when it has momentum behind it...
Of course it's not a "non-starter" for as long as Swanson's Law keeps going - and it shows no change I can see of stopping. Payoff times of a few years not unrealistic if trends on cost reduction in solar and storage keep going as they are.
otolith said:
The main problem with mass and efficiency is that the amount of energy you have to throw away whenever you use the friction brakes is proportional to the mass of the car.
The reason mass is much less of a problem with electric and hybrid cars is that they have the option of not using the friction brakes and instead recovering a good chunk of that energy into the battery.
Yea, this is obvious and nobody is denying it. But my initial post was a response to someone saying that in some cases it was actively better for electric cars to be heavier. Which can never be true.The reason mass is much less of a problem with electric and hybrid cars is that they have the option of not using the friction brakes and instead recovering a good chunk of that energy into the battery.
Polite M135 driver said:
otolith said:
The main problem with mass and efficiency is that the amount of energy you have to throw away whenever you use the friction brakes is proportional to the mass of the car.
The reason mass is much less of a problem with electric and hybrid cars is that they have the option of not using the friction brakes and instead recovering a good chunk of that energy into the battery.
Yea, this is obvious and nobody is denying it. But my initial post was a response to someone saying that in some cases it was actively better for electric cars to be heavier. Which can never be true.The reason mass is much less of a problem with electric and hybrid cars is that they have the option of not using the friction brakes and instead recovering a good chunk of that energy into the battery.
Driving experience of course is always better lighter, but - we're not talking about fun cars here: we're talking about "transport"....
Polite M135 driver said:
otolith said:
The main problem with mass and efficiency is that the amount of energy you have to throw away whenever you use the friction brakes is proportional to the mass of the car.
The reason mass is much less of a problem with electric and hybrid cars is that they have the option of not using the friction brakes and instead recovering a good chunk of that energy into the battery.
Yea, this is obvious and nobody is denying it. But my initial post was a response to someone saying that in some cases it was actively better for electric cars to be heavier. Which can never be true.The reason mass is much less of a problem with electric and hybrid cars is that they have the option of not using the friction brakes and instead recovering a good chunk of that energy into the battery.
otolith said:
Polite M135 driver said:
otolith said:
The main problem with mass and efficiency is that the amount of energy you have to throw away whenever you use the friction brakes is proportional to the mass of the car.
The reason mass is much less of a problem with electric and hybrid cars is that they have the option of not using the friction brakes and instead recovering a good chunk of that energy into the battery.
Yea, this is obvious and nobody is denying it. But my initial post was a response to someone saying that in some cases it was actively better for electric cars to be heavier. Which can never be true.The reason mass is much less of a problem with electric and hybrid cars is that they have the option of not using the friction brakes and instead recovering a good chunk of that energy into the battery.
SpeckledJim said:
The point I was trying to make was slightly different.
A heavy ICE car is always bad news. It costs more energy to get it up to speed, and then if you brake, you swap that energy to a large amount of heat in the brakes.
Whereas a heavy EV isn't so bad. Yes, it costs more energy to get up to speed, but on slowing down, the weight counts in your favour, rather than against you, as a heavy car will be able to recover more energy than a light car will.
A heavy battery is usually bad news, and sometimes good news. Whereas a heavy ICE is always bad news.
Which (clearly to me?) doesn't say that it's better overall to be heavy. A heavy ICE car is always bad news. It costs more energy to get it up to speed, and then if you brake, you swap that energy to a large amount of heat in the brakes.
Whereas a heavy EV isn't so bad. Yes, it costs more energy to get up to speed, but on slowing down, the weight counts in your favour, rather than against you, as a heavy car will be able to recover more energy than a light car will.
A heavy battery is usually bad news, and sometimes good news. Whereas a heavy ICE is always bad news.
What it says is that if you're heavy, it's better to be an EV than an ICE.
Adding 100kg to your car is less of a problem if the car has regenerative capability than if it doesn't. Don't think that's contentious?
SpeckledJim said:
What it says is that if you're heavy, it's better to be an EV than an ICE.
Adding 100kg to your car is less of a problem if the car has regenerative capability than if it doesn't. Don't think that's contentious?
ICE w/Hybrid. We're comparing shiny new EVs with the worst petrol cars. Let's compare say a Honda NSX (which is a few years old) with an EV. or the energy recovery tech in a F1 car. It's not a level-playing field - pretty sure an NSX-2 made now with the latest battery and ICE technology would be doing 2.0second 0-60s.Adding 100kg to your car is less of a problem if the car has regenerative capability than if it doesn't. Don't think that's contentious?
Edited by fido on Wednesday 9th June 11:45
fido said:
That completely depends on the power supply. If it's from a power station then the energy conversion alone could be 35-60% (gas-fired). Don't get me wrong I do love all the new technologies that are coming on board but I think pure-electric is as myopic as those who touted it at the start of the twentieth century. And they were very popular until ICE vehicles improved.
https://archive.curbed.com/2017/9/22/16346892/elec...
As i wrote i am talking about at the "Car" level.. Be that the plug from your charger you stick in the side, or the nozzle from the petrol pump you stick in the side.https://archive.curbed.com/2017/9/22/16346892/elec...
Edited by fido on Wednesday 9th June 00:08
At this point, the EV sits at around 85% (energy to useful work, ie moving the car around) and an ICE sits at around 22% (typical in the uk)
It gets so much worse for the ICE when we start to include the extraction, refinement and supply chain.
It also is extremely important to understand that an EV is completely agnostic to the source of it's electricity. You could charge it from solar, wind, hell, you could put a generator on a stationary fitness bike and charge the thing yourself if you wanted (best make sure you've had yor weetabix, mind, a 1 kWh is a fair huff puff for a puny human ;-)
How impactful your electricity supply used to charge your EV depends very much where you are in the world. In the UK, our grid last year was on average at 181 g/kWH of CO2. An EV driven in typical uk conditions and speeds does about 3.5 ml/kWh, so just plugged into the grid, a typical EV has a virtual tailpipe emission of 51 g/ml or 32 g/km
An diesel ICE doing 50 mpg has a tailpipe emission of 150 g/km. For every single mile driven it's putting out an additional 118g of Carbon Dioxide. Drive 100 miles and that's 12 kg of extra carbon! On a yearly 7,000 mile typical useage, that's 826Kg, or 417,171 litres more carbon emissions!
And an often missed fact is that absolute efficiency is one thing, but the profile of that efficiency over the distribution network matters as well.
Imagine i have a horse that eats apples and It needs 10 apples a day.
Unfortunately it's a messy eater and drops and looses 8 of those apples (20% efficient, same as your car...) To make sure it eats 10 apples i have to carry a bucket with 50 apples to it each and every day. But carrying that bucket has an efficiency too. It takes effort and i might drop it or loose a few apples out of it. Let say i loose 10%, so now i need to start with 55 apples my bucket!
If my horse was a more careful eater, i would not only have to carry less apples, but at the same 10% loss, i'd loose less apples each day too. (50% efficient eater, 10 Apples per day requires 20 apples in bucket, so 10% loss means i need to start with 22 apples, a loss of 2 apples in the system)
An ICE Is terrible, because it is catastrophically wastefull of the energy supplied to it, and because it is the last thing in a massive supply chain, often starting miles under ground, under hundreds of meters of water in the middle of a sea or ocean!
Killboy said:
Why? Why not compare shiny new EVs with shiny new ICEs?
Because only a few relatively small companies e.g. Mazda, Ferrari are pushing that technology into their road cars. Go back to my link about electric cars in the 20s - it was an 'easy' solution then and it is the 'easier' solution now. F1 is different in that the brightest and best look for the most intricate solutions - for example the ERS is 96 percent (according to an AMG article) and has only been around for a few years. Diesels were mega-popular for the last decade because the government pushed manufacturers that way and now it's EVs. It reminds me of The Current War between Edison and Tesla - instead of using animals to demonstrate that AC is unsafe - we've got Greta and co. telling us bad man use hydrocarbon-powered vehicles.Edited by fido on Wednesday 9th June 11:58
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