Mar 16 2009

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a thirteen amp plug just won’t cut it

I normally read the register for its IT tech related reporting – and I enjoy it just because it is a wonderfully scurrilous rag. However, an article about the Swedish supercar maker Koenigsegg’s “Quant”, which el Reg chose to call “Mary”, piqued my interest somewhat. I can’t quite make the arithmetic work out. To quote the article:

“The Mary has a top speed of 275kph (171mph), a 0-62 time of 5.2 seconds, a range of 500km (312 miles) and is powered by two electric motors pumping out a combined 512bhp (381kW) of power and 715nm (527lb ft) of torque.

While Koenigsegg is shy on exact technical details, its press release abounds with interesting ‘facts’ – including the claim that that it will be possible to charge the Mary’s NLV-developed “redox FAES (Flow Accumulator Energy Storage) to full capacity in 20 minutes and give the vehicle a range of 500 kilometres”.”

Now we if we unpick that a bit we get the following:

– the car uses 381kW of power at peak – let’s say a maximum 200kW at a sensible cruising speed of 100 kph.
– it can travel for 500 kilometers on one charge.
– it can be charged to capacity in 20 minutes.

Now 500 kilometers at 100 kph is 5 hours travel. Multiply that by 200kW and we get 1000kWh. But it can be charged in 20 minutes, so the charge rate must be three times that – i.e. 3000kWh.

No way can you get that through a 13 amp socket.

Permanent link to this article: http://baldric.net/2009/03/16/a-thirteen-amp-plug-just-wont-cut-it/