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Not the Olympics

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Not the Olympics

As an antidote to the Olympic chat, here's a geeky topic in The Register. Using nano-technology the Koreans have developed a technique to enable recharging of Lithium Ion batteries in a few minutes. Just think of the impact on your laptop computer, mobile phone, electric car.
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Re: Not the Olympics

Why does that ring an old bell Undecided
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Re: Not the Olympics

I'm not sure Strat, sounds like new technology to me. However the tiny fly in the ointments for using this for charging electric car batteries in 20 minutes is having a charging system capable of delivering 100 KW/Hours in 20 mins. I guess it is not your average 13 amp plug.
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Re: Not the Olympics

Quote from: AlaricAdair
nano-technology

aka "fairy dust"  Roll eyes
Another interesting problem, apart from how to deliver so much energy in a short time is whether or not there is some "thermal inefficiency" in the recharging process.
i.e. does the battery warm up (as all current ones do) during charging.
Could be explosive!  Crazy
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Re: Not the Olympics

Being a curious soul and an engineer to boot I thought I would do a bit of calculation
Chevrolet Volt - range 40 miles
Battery capacity from minimum to full charge 10.3kwh
Battery pack voltage 300v
Total power to recharge in 20 minutes ignoring efficiency
30.9kw so about 103 amps at 300 volts
Not too bad until you want 120 mile range and then it jumps to over 300 amps - that is a very thick wire  Shocked
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Re: Not the Olympics

Quote from: Oldjim
over 300 amps - that is a very thick wire  Shocked

Hmm, not really. Check the CCA on your car battery - mines about 800.  Cool
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Re: Not the Olympics

Voltage?
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Re: Not the Olympics

Quote from: AlaricAdair
I'm not sure Strat, sounds like new technology to me.

Yeah....probably something I read a few months back regarding attempts to do what these guys seem to have achieved.
Quote from: Oldjim
over 300 amps - that is a very thick wire  Shocked

Maybe some cryogenic cable needed here......and a big bag full of shillings for the meter.
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Re: Not the Olympics

Quote from: HPsauce
Check the CCA on your car battery - mines about 800.  Cool

The battery may be able to supply 800A, but not for very long, and also the wires to the battery would become fuses after a few seconds of continuous use at that current.
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Re: Not the Olympics

How long a car battery supplies current isn't the question, I was just drawing a comparison to the charging current required for one of these "new-fangled" fairy-dust batteries pointing out that the cabling may not be as humungous as might be anticipated.  Cool
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Re: Not the Olympics

According to my old copy of Regulations for the Electrical Equipment in Buildings 300 amps would need a conductor of 120 sq mm and as it would need to be flexible it would have a maximum diameter wire of 0.51mm making up the conductor
This would require about 590 wires making up the core and the approximate diameter of the cable (you would need two plus an earth in total) would be 14mm
So you would have 2 x 14mm diameter plus 1 x 8mm diameter (earth) giving an approximate overall diameter of about 35mm
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Re: Not the Olympics

That's not radically different to the overhead mains cables down our road.  Cool
And the cables into our domestic meter are about 10mm dia each (including insulation).
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Re: Not the Olympics

You must have really thick cables as mine aren't that thick and the supply is rated at 100 amps - i think they are about 8mm diameter and I am not  going out to measure them  Huh but that does match up to the standard
The big difference is that they only have about 8 to 12 strands as they aren't classed as flexible
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Re: Not the Olympics

Quote from: Oldjim
You must have really thick cables

We do.
I think when initially installed they used the same cable as the main overhead trunk up the road, i.e. 2 thick cables (no separate earth, neutral is earthed at alternate posts according to some overhead line engineers I spoke to once).
Subsequently that was replaced with a single cable (presumably twin-core plus strain relief and outer cover) but it was "grafted" onto the existing wiring after coming through our wall.
Still just 100A big fuse though.
Still puts 300A at 300V in context though, perfectly "do-able".  Cool