Author Topic: Electric cars  (Read 697631 times)

Jocko

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Re: Electric cars
« Reply #780 on: February 24, 2018, 02:57:55 PM »
We used lots of Variable speed 3Ø motors and they were extremely reliable and exceptionally low maintenance. DC motors, on the other hand, were the bane of our life with hours of maintenance work ever year.

Jocko

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Re: Electric cars
« Reply #781 on: February 25, 2018, 08:33:39 AM »

Jocko

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Re: Electric cars
« Reply #782 on: February 27, 2018, 09:50:59 AM »
I see CO2 emissions are up due to the dive in diesel sales and upsurge in SUVs. Sooner we get EVs the better.
http://www.bbc.co.uk/news/business-43204734

sparky Paul

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Re: Electric cars
« Reply #783 on: February 27, 2018, 10:20:11 AM »

culzean

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Re: Electric cars
« Reply #784 on: February 27, 2018, 10:32:46 AM »
Big problem with capacitors of any kind (which store electrons / electricity rather than a chemical reaction) is that as they discharge the terminal voltage drops rapidly, this is unlike a battery where the voltage stays pretty constant until they are almost fully discharged. When talking about batteries and capacitors you have to differentiate between energy and power.

https://www.tecategroup.com/ultracapacitors-supercapacitors/ultracapacitor-FAQ.php

in the section comparing batteries with capacitors these people have used the old trick of making the vertical axis of their 'graph' non linear (in fact it is a logarithmic scale) which makes the 'energy density' of capacitor seem better than it is.

So called 'super-capacitors' are good at delivering a lot of current for a short time.  so can help a battery,  but they are not so good when they get discharged at a longer rate, and capacitors are not good at holding a charge for longer periods,  it just leaks away.
« Last Edit: February 27, 2018, 11:09:17 AM by culzean »
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sparky Paul

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Re: Electric cars
« Reply #785 on: February 27, 2018, 12:03:39 PM »
Even with current technology, it's not difficult to convert a discharge curve from a supercapacitor into steady DC with minimal losses.

The rate of storage technology development is bound to increase, particularly now there's greater appetite for it - necessity is the mother of invention. However, it may take many years for a single, effective technology to emerge.

culzean

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Re: Electric cars
« Reply #786 on: February 27, 2018, 12:15:22 PM »
Even with current technology, it's not difficult to convert a discharge curve from a supercapacitor into steady DC with minimal losses.

The rate of storage technology development is bound to increase, particularly now there's greater appetite for it - necessity is the mother of invention. However, it may take many years for a single, effective technology to emerge.

If you look at the capacitor manufactures site in link capacitors are great at power storage but absolute crap at energy density - its not easy to get voltage when there isn't any there.  Capacitors in series (they have such a low voltage per capacitor they have to be connected in series to get anything) also have the nasty habit of getting unbalanced charges, to cure this they have to get a resistor connected in parallel to equalise the voltage across each capacitor)  - but that same resistor is a discharge path for the capacitor - this has always been a problem with capacitors.  They are good for regenerative braking (they can absorb a charge very quickly) and good for very short term boosting (they can release a charge very quickly) - but different characteristics to a battery altogether.

More 'tomorrows World' stuff from EV makers,  fingers crossed that something happens lads. If hype could be translated into actual power we would have 500 mile range from a battery / capacitor the size of a matchbox which would charge up in 20 nano-seconds.
Some people will only consider you an expert if they agree with your point of view or advice,  when you give them advice they don't like they consider you an idiot

sparky Paul

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Re: Electric cars
« Reply #787 on: February 27, 2018, 02:11:09 PM »
If you look at the capacitor manufactures site in link capacitors are great at power storage but absolute crap at energy density

The teams at Bristol and Surrey Universities reckon the polymer they are developing will be 50% more energy dense than lithium-ion. My point is that after years of slow progress in battery technology, efforts are being made to actively look for new technologies & materials.

Jocko

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Re: Electric cars
« Reply #788 on: February 27, 2018, 03:07:40 PM »
A quantum leap in technology is a quantum leap, because it is a breakthrough, not just the evolution of a technology. A jump most people were not expecting. Supercapacitors may well be that for energy storage.

guest4871

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Re: Electric cars
« Reply #789 on: February 27, 2018, 05:15:12 PM »
A quantum leap in technology is a quantum leap, because it is a breakthrough, not just the evolution of a technology. A jump most people were not expecting.

I was reading at the weekend that 30% of the cars in the US were electric until Henry Ford arrived with his Model T.

Jocko

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Re: Electric cars
« Reply #790 on: February 27, 2018, 06:17:18 PM »
News today from Germany. After a landmark court ruling, cities are going to be allowed to ban older diesels, like London's Toxicity charge. Add to that the fact that Geely has just bought 9.7% of Daimler, the owner of Mercedes Benz. Geely is hugely into EVs and already owns Volvo and London Taxi company.
EVs are going to be big in Germany.

Jocko

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Re: Electric cars
« Reply #791 on: March 01, 2018, 07:26:06 AM »
I see Dyson are trying to recruit another 300 engineers as it pushes to have an EV by 2020.
http://www.bbc.co.uk/news/business-43236619

culzean

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Re: Electric cars
« Reply #792 on: March 01, 2018, 09:15:36 AM »
I see Dyson are trying to recruit another 300 engineers as it pushes to have an EV by 2020.
http://www.bbc.co.uk/news/business-43236619

Anyone remember Clive Sinclair (Sir) and his C5 - I am getting Deja-vu all over again.......
Some people will only consider you an expert if they agree with your point of view or advice,  when you give them advice they don't like they consider you an idiot

Jocko

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Re: Electric cars
« Reply #793 on: March 01, 2018, 09:34:13 AM »
Anyone remember Clive Sinclair (Sir) and his C5 - I am getting Deja-vu all over again.......
I feel a bit like that myself!

richardfrost

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Re: Electric cars
« Reply #794 on: March 01, 2018, 12:28:33 PM »
I have come to the conclusion that research into electric cars is not very imaginative. For me, there should be three streams of work...

1. Power storage and delivery, i.e. batteries, capacitors, fuel cells, hybrids of these
2. Motive power, i.e. the future of motors
3. Car design, i.e. stop thinking about how to fit batteries and motors into existing car shapes designed for engines up front, fuel tanks underneath and drive shafts up the middle. Think imaginatively about how new technology could encourage different designs, and not just bland cubes on wheels.

Dyson is seen as some kind of design guru but he has basically reused age-old centrifuge designs to create cleaners which are filthy to empty and hand driers which blow contaminated air drawn from the public toilets onto your hands at high speeds. I wonder how inventive their car designs will be.

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