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Wed 9 Jul 2014 16:12

Any - Analysis of Rechargeable Battery - Electric Cars - Firmbutfair

Given that for every 10 kWh (units) of electricity made 'available for use' in our homes, the far distant, Midlands based fossil fuel (coal or natural gas) powered power station has to generate 37kWh of 'heat energy' then surely it makes much more economic and ecological sense for us to generate our own electricity as close to home as possible? (This is because 27 units of the 'heat energy' generated at the 'distant' power station is 'lost' in the generation process and in its journey of many, many miles over 'lossy' overhead power lines from the 'furnace/boiler/generator' to the wall socket in your home). Similarly, if nuclear power is used to replace the fossil fuel 'furnace' the remaining stages of generation, transmission and distribution are subject to the same 'heat losses' as are involved in those same process stages in the fossil fuel case.

The nominal efficiency of the process is further diminished in the use of mains electricity in our homes to charge up the 400 volt 5/10/22/24 kWh 'battery' in an electric (EV) or in a petrol-electric hybrid (PEHV) car or motorcycle. Typically between 30 and 50% more electricity than is actually stored as usable energy in the battery, has to be 'drawn from the mains' in the battery charging process. Finally the conversion of stored electrical power in the battery to motive force in the car is no more than 85% efficient. Thus 'doing the maths' we can see that for the EV or PEHV, the 'conversion efficiency' from power station to 'motive power on the road' is between 10/37 x 1/1.5 x 0.85 = 0.153 and 10/37 x 1/1.3 x 0.85 = 0.177 i.e. the conversion efficiency is between 15% and 18% with a typical value of 16.4% for coal fired electricity generation. In contrast the conversion efficiency between petroleum based fuels burnt in an internal combustion engine (ICE) and 'motive power on the road' is typically around 18%.

If the petrol/diesel burning ICE had been 'invented' before the electric car and the steam engined car were introduced in Europe, towards the end of the 19th Century, then the electric car would probably never have been seriously considered for anything other than certain 'niche' applications such as milk delivery 'floats' since the 'start/stop' nature of this activity is ideally suited to rechargeable battery-electric propulsion. (Milk delivery floats, and golf buggy carts, commonly seen in the mid to late 20 th century even used heavy Lead-Acid batteries and yet they seemed to work satisfactorily).

P.S. As a final example of benchmarking 'comparison' - the 'conversion efficiency' of solar energy to 240 volt rms a.c. electricity, using modern, roof mounted domestic solar panel arrays etc, is around 15% - makes you think doesn't it ?

Do I feel a range of futuristic, Hydrogen Fuel Cell based, electric, light weight, personal transport vehicles with their associated, supporting, geographic, Europe wide infrastructure coming along in the next decade or so ?

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Wed 9 Jul 2014 16:29

Any - Analysis of Rechargeable Battery - Electric Cars - liammcl

I'm no expert ...by any means, what so ever !:)

...but you may find these "illuminating" ;)

Human generated power ...

Pavements
edition.cnn.com/2011/10/13/tech/innovation/pavegen.../

Gyms etc
www.utilitycharges.co.uk/human-powered-electricity...l

www.independent.co.uk/environment/climate-change/m...l

blog.chron.com/sciguy/2010/02/are-you-ready-to-bec.../

These are just links thrown in ...

Also, maybe with new materials,
(eg graphine etc, increasing conductivity, while reducing weight)
could see a lot less energy being neede to propel a vehicle along ?

www.graphene.manchester.ac.uk/#/explore/the-applic.../

Is the reliance on oil, politically driven?

I know nothing ...I'm just throwing a few ideas about

*edit*...off topic ...heat pumps for the home?
energy.gov/energysaver/articles/heat-pump-systems

Cheers
Liam

Edited by liammcl on 09/07/2014 at 16:38

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Wed 9 Jul 2014 17:59

Any - Analysis of Rechargeable Battery - Electric Cars - Bolt

I read somewhere the use of lead acid batteries could be used instead of lithium ion in petrol/diesel electric cars, as its possible now to store more in them.

But imo all electric cars will not become the norm

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Thu 10 Jul 2014 12:06

Any - Analysis of Rechargeable Battery - Electric Cars - Firmbutfair

Thanks for the links to pavement generators, peizo-electric clothing and graphene Liam.

It would appear that we have a lot of promising developments to look forward to in the near future, e.g. I did not know that graphene absorbed light and stored it as electric charge - very interesting. I guess that the idea of making a motor vehicle body from multiple graphene batteries (to save the additional weight of separate batteries) could therefore be supplemented by graphene solar panels ?

Trevor Bayliss and his hand wound generators for radios and torches etc is a very clever man. I have one for emergency use to charge my mobile phone and my tablet PC.

For my own part I very much favour walking, or cycling (with the necessary high visibility vest and cycle helmet of course) and mass transit systems (railways) for my modes of transport, but my wife and I still manage to 'clock up'' over 8000 miles a year in our family hatchback !

I am also following the development of Hydrogen Fuel Cell driven electric vehicles with great interest and the latest hydrogen generators in the form of the Proton Exchange Membrane Electrloyser looks promising too. Clearly 'change for the better' in modern society will be slow as there is such an enormous ammount of wealth already invested in oil, (petro-chemicals) and other fossil fuel based economies. So for now - why not just have a good breakfast and then cycle to your local tele-working-office-centre for four days per week - or even just 'work from home' if your employer is agreeable. BT began a 'working form home' trial with many of its professional engineering staff over 15 years ago, to enable both the practice and the technology to be evaluated - but I am not sure how widesapread it is in general nowadays! I imagine that working from a local tele-centre would be the option preferred by most employers and employees as 'working from home' can be very stressful with all the normal everyday domestic distractions to deal with. Good luck with your Piezo Pavements etc :-)

Edited by Firmbutfair on 10/07/2014 at 12:09

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Thu 10 Jul 2014 13:01

Any - Analysis of Rechargeable Battery - Electric Cars - liammcl

Cheers :)

A quick scan, of the interknitwerk ;)....

"Modern gasoline engines have a maximum thermal efficiency of about 25% to 30% when used to power a car. In other words, even when the engine is operating at its point of maximum thermal efficiency, of the total heat energy released by the gasoline consumed, about 70-75% is rejected as heat without being turned into useful work, i.e. turning the crankshaft. [1]
(en.wikipedia.org/wiki/Engine_efficiency)

If the friction of moving parts , tyres, and the weight reduced,
the power needed for an electric motor could be reduced a lot...
maybe higher temp. superconductivity would allow direct power from sunlight?
www.simonsfoundation.org/quanta/20140430-decoding-.../

for an electric motor
"Efficiency for an electric (a BLDC) motor of up to 96.5% have been reported, [64] whereas DC motors with brushgear are typically 75–80% efficient."
(en.wikipedia.org/wiki/Electric_motor)

I, myself, have an electric bike (2nd hand £80)
which I addded few lead acid batteries (£45) to give 1 horse power
...it does about 20 miles at 18mph, effortlessly.

Sometimes I use that for work (mobile computer repairs) if the weather is good, and also to give my knobbly knees an airing :)
s103.photobucket.com/user/liammcl_2006/library/Ele...4

to recharge it, uses less power than a laptop, eg 2p , and the bike can be put of trains for free.

If I lived somewhere sunnier, i would definitely use the bike for trips to the supermarket etc a lot more

Cheers
Liam

Edited by liammcl on 10/07/2014 at 13:06

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Tue 15 Jul 2014 14:51

Any - Analysis of Rechargeable Battery - Electric Cars - Firmbutfair

I love the description of your electric bike LIAM. This is clearly the way to go for future personal transport - my conventional push-bike and I weigh less than 90 kg - when standing on the bathroom scales, dressed up and 'road ready', holding the bike above the ground. Thus I am both 'passenger and motive engine' and the bike reperesents just a very small 'overhead' of say 15 kg which is approx 20% (90 - 75 kg). Clearly adding a battery driven electric motor is not going to 'spoil' this initial 'basic model'. If your '20 miles at 18 mph effortlessly' is mostly on battery power, with say just a little help from you pedalling on the uphill bits, then you already have a machne that more than competes with commercial offerings costing in excess of £300 to £800 - well done you !

The modern popularity for 'his and hers' motor cars - used nowadays as a 'human right' and as 'an essential means of personal transportation', is perhaps the most inefficient, stupid 'application' (of a perfectly good invention) known to man. Yes, cars are safer and offer superior weather protection etc but a lot of the lack of safety associated with cycling is due to greedy, selfish, ignorant, careless, poorly trained car drivers who seem to be incapable and/or unwilling to 'share' the public highways with pedestrians, cyclists and lightweight motor cyclists, who whilst 'but they pay little or no VED' do, for the most part pay significantly more than any VED - in Council Tax for the privelege of using the roads and pavements. I am a regular car driver with at least one passenger and often with three or four passengers, but I am also frequently a pedestrian and a cyclist and I have lost count of the times that my wife and I have had to take 'emergency evasive action' whilst cycling or walking together to avoid so called 'collisions' with careless and discorteous van and SUV drivers and the like. Here's hoping for a day in the not too distant future when employees, householders and school children travel just a few miles to their normal place of work, stufy or to the local shops - on foot , on a bike or an efficient public transport service...!

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Wed 16 Jul 2014 00:12

Any - Analysis of Rechargeable Battery - Electric Cars - Peter.N.

Most of the modern developments in electric vehicles have been due to the availability of lithium batteries which have a much better capacity/weight ratio but these are expensive and not without risk but whatever inefeciencies there are in mains electric charging the fact remains that to the consumer they are much cheaper to run than an internal combustion engine, althought these are improving all the time.

The real use of electric cars would be best confined to the 'second' car that never does more than 20-30 miles a day in an urban or suburban area. These could be built with far fewer lead acid batteries thus reducing the weight and cost, with a range of say 50 miles and a top speed of about 40 mph, these would be much cheaper to build and maintain.

In the early days of powered road transport a high proportion of vehicles were electric, in fact there were still quite a few about in the '50s when I worked in London, Harrods were one of the firms still using them. As people became better off after the war and fuel was relitively cheap they lost favour but they could still be used in situations where the internal combustion engine is at its least efficient.

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