* Posts by Mark Harrison

3 posts • joined 21 Jun 2007

Motorbike crash man fails to notice loss of leg

Mark Harrison

Arrived at the junction...

I think some of your correspondents are missing the point about being able to operate the rear brake, the article clearly says "He clocked his loss when he subsequently arrived at a junction". It appears as though a zealous editor may have removed Lester Haines further comments of, "... and raced through it at 100 mph".

Was his failure to operate the rear-break what caused him to "clock his loss"?

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Quick-charging electric cars could be round the corner

Mark Harrison

Re: Charging capacitance

Bob, you are right, as the simple ideas are the best. From what I remember of being a distracted youth in Physics, capacitors are not great at holding the charge efficiently so what would the true cost of running the car be. The garage may waste 50% of the energy consumed during the times when nobody is "filling up".

I think Service Stations will not offer the theoretical maximum current to drivers, considering it best to give them 15 minutes to browse the shops as their car is juiced up.

Aside: will this mean an end to the much-debated mobile phones ban on forecourts? The warning posters could be re appropriated to warn motorists not to connect their phone to the 500KVA supply?!?!

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Mark Harrison

Realistic use scenario

I think that the comments above should be considered in a realistic usage scenario. I drive 50 miles to work and back each day. This is within the range of current battery-powered cars. Occasionally I drive 500 miles to London and back.. This is outside the scope of battery powered cars so I would never buy one.

If I assume that I am Mr Average, 1% of my journeys would require me to complete a fast charge mid-journey. The remaining 99% would be taken from my domestic connection in my garage overnight (I don't have off-street parking at the moment, so it may prove tricky).

On those (let's say) four occasions a year I do go to a Service Station on the M1 the provider of my 7 billion amps (what did we decide on?) will charge me my left arm and half of my right leg to use their fast-charge service compared with my Economy 7 overnight feed running across the pavement. The govt. will want to support electric cars, so will not charge me too much tax, meaning it will still be cheaper (the consumer's raison d'etre) for me to do a fast charge on the M1 than use a hydrocarbon fuel.

I've got a car that will be green (on slow charge), will have the range I need (on fast charge) and will be cheaper and cleaner to run overall.

Service Stations providing the electricity charging may have to invest in expensive equipment and have their own substation, but they work in a changing market and are in business so will respond (LPG availability is growing). They only really make serious money from cigarettes, bottled water and chocolate bars, don't they? Green subsidies will be on offer, too.

I think that the fast-charge battery of cells will help make positive decisions to buy electric cars easier by removing the range issue, even though the fast-charge is only used occasionally; I like my aircon, I rarely use it, but chose my car because I wanted it to be available for when I do need it.

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