The wallet-lightening Lightning

2 September 2007


Yesterday’s Telegraph included a fine article on Britain’s answer to Californian electric car company Tesla: the Lightning Car Company.

The two firms are not quite aiming for the same outcome – Tesla’s roadster is due to set owners back about £50,000, while the British company is asking for the same sum just as a deposit. When the Lightning eventually turns a wheel under a paying customer, it will have lightened their wallet to the tune of £150,000.

The Lightning’s aluminium honeycomb and carbon composite monocoque looks attractive – albeit in a kind of stuck-in-the-60s fashion – and the chassis will be four-wheel drive via hub-mounted motors. It’s a shame, then, that the car must suffer from such a long nose, which puts the driver’s bum a long way rearward within the wheelbase. This is not great for driving feel, nor vision at junctions, and is flatly nonsensical in a car that won’t have an engine under the bonnet.

The wheel motors that will stand in for a rumbing V8 will be supplied by a small UK company called PML Flightlink, which developed them with automotive intentions prior to the Lightning link-up. In August last year PML showed off a proof-of-concept electric vehicle based on a BMW Mini to demonstrate its technology. The deal with Lightning is not exclusive – so we can expect to hear more from PML and its “Hi-Pa Drive” motors.

The batteries will be supplied by Altair Nano of Nevada, and are reportedly top-notch, cutting-edge stuff in the world of cramming electrons into small spaces. However, the Telegraph blindly passes on the incredible claim that a 10 minute charge will yield 90 percent capacity and a 200-mile range - in a sports car designed to go haring around at high speed.

The paper neglects to mention what this might involve, but to its credit the Lightning company does explain a little more fully in the Q&A section of its web site: “Standard single-phase home-type power source can be used to charge overnight... For a fast charge a 3-phase power supply is required.”

So yes, for a fast charge owners will be mucking about with 415-volt industrial power cables. Which can be a bit on the dangerous side. We advise potential owners not to try unplugging the car in the rain, unless they wish to witness real lightning at close quarters.

3 comments:

Technopete said...

Yet again Auto IT shows a disregard for homework and detail. If you look on the Lightning site you link to then you will find that the charging cable used is the same, whether you charge from a single phase or 3-phase power source.

Further, if you look up 3-phase power on Wikipedia, you find that the voltage to ground is a maximum of 240 volts for any phase. You only get 415 volts because the voltage on one phase can be negative while on another it is peak positive (e.g. 240 volts), so the maximum difference between the two phases is 415 volts. But you would have to grab the cable for one phase in one hand while touching another phase with the other to get above 240 volts.

Why have you got this thing against electricity anyway? An electric car will reduce the total energy consumption by a factor of 2+ and the CO2 emissions by a factor of 4+ (for the current mix of electricity generation fuels), with the potential of further reductions as electricity generation goes more towards renewables. Further, the emissions of other pollutants are a few percent of those caused by petrol / gasoline. And look at the acceleration you get....

Auto IT said...

Yet again technopete shows an unhealthy disrespect for the dangers of electricity.

240V is quite enough to burn or even kill and unlike a domestic power supply, which will blow a fuse or trip a switch at 13 amps, a three-phase supply configured to charge the Lightning in 10 minutes will need to deliver hundreds of amps before it detects a problem.

For example, the battery in the PML demonstrator stores 21kWh, and it seems likely that this is smaller than the battery envisaged for the Lightning. To charge PML's battery to 85% capacity in 10 minutes, assuming a very generous 100% charging efficiency, requires all three phases to deliver about 150 amps, for about 450A in total. Ask an electrician - this is very dangerous territory.

Auto IT is not against electric cars - Auto IT is a determined fan of electric cars. It is glib statements about 10-minute recharging times that are the problem.

For the record, Auto IT's author trained as an electrical and electronics engineer to PhD level and does not need to look up three-phase on Wikipedia.

Auto IT said...

Anyone interested in charging electric vehicles should follow the comment threads at the Tesla Motors blog post "Electrical Survey".

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