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Question on electric cars coming in the future

  1. Aug 14, 2008 #1
    Hi. I've been planning to get an electric car around 2010 or after when most manufacturers will have cars out. After some searching I've seen Chevy will have their Volt which can go 40 miles on a charge. Mitsubishi is making one (the Colt) that will go 90 miles on a charge. I'm not sure of the charge times of the two cars but I think they are relatively long. Then I find Lotus teaming with Zap to make a car that goes 350 miles. This Lotus will be 4-6 times more powerful than the former cars also (I'm assuming). Also the Lotus car will be able to charge in 10 minutes.

    Now here are my questions,
    How does the Lotus car get such a big difference? I'm imagining that Lotus has better engineers? Maybe they're engineering systems on the car that will charge the battery on deceleration (like Prius cars do) and then another system that "supercharges" the car during acceleration? By supercharging I mean giving it extra power to accelerate, like superchargers do on petrol cars.

    If I remember my electromagnetism correctly, could they be doing something like wrapping the axles with coiled wire and magnetizing the axles? Doing this, as you accelerate the axles turn faster and faster creating bigger and bigger current. The increasing current could produce and increasing magnetic force that can help propel the vehicle.

    Then when the driver releases the "throttle" the vehicle switches this system to a charging system to charge the battery.

    I'm curious to figure this stuff out so maybe it'll be possible to buy an electric Colt, for example, and outfit it with a "supercharging" system.
  2. jcsd
  3. Aug 14, 2008 #2


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    The lotus uses electric motors in the wheel hubs. The chevy is a hybrid vehicle so keeps the existing engine and power train and adds an electric motor. Both can do regenerative braking = using the motor as an alternator to recover energy and increase battery life.
    edit - The chevy is a little smarter than existing hybrids like the prius, it runs on the electric motor all the time and uses the IC engine to power it when needed, this makes the drive train simpler.

    The main difference with the lotus is likely to be the batteries, the ones in the chevy need to built for a mass market - taking into account price, lifetime, reliability etc. The lotus battery technology isn't published but it's going to be a bit more specialised.
    I'm not sure I believe the 10min chargeup, I suspect that some marketing spin is involved, it's a 10min top-up.
    Last edited: Aug 14, 2008
  4. Aug 14, 2008 #3
    I have heard that the Tesla (an obvious tribute to Nikola) is quite a performer.


    ...and not bad looking.
  5. Aug 14, 2008 #4
    I see. So this Lotus car is 4-6 times more powerful because it has 4 motors rather than 1 like the Volt?

    Why couldn't these makers harness the vehicle's momentum and turn that into electric energy too? I'm talking about while accelerating.
  6. Aug 14, 2008 #5
  7. Aug 14, 2008 #6
    You cannot get more energy out of a system than you put into it. PERIOD!! Whatever energy you get out of whatever system you use to get it will have come from the battery...and you won't get all of it back.

    In a sense, they are harnessing the momemtum when they use generation in the motor to slow the car and charge the battery (taking the place of scrubbing off the kinetic energy by heating the brake discs)...but that only works in deceleration.
  8. Aug 14, 2008 #7
    I remember now. Putting 4 electric motors parallel, all 4 will get equal amounts of current (current takes path of least resistance). So the differences in power of the cars is in the battery.

    Do inductors produce an opposing force to a magnetic field moving through it? This area I forgot. I see the energy stored in an inductor is equal to the amount of work required to get the current moving through it. This is why this inductor effect isn't used during acceleration?
  9. Aug 14, 2008 #8


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    No, but it might be lighter since it doesn't have a transmission, differential and drive shafts. As you said the power is limited by how much you can take from the battery.

    It's not really correct to call it an inductor.
    An electric motor also behaves as a generator. If you put electricity in it turns, alternatively if you turn it you get electricity out. Exatcly the same motors are used to charge the batteries under breaking. All the brake pedal does is reverse the connections to the battery.
  10. Aug 18, 2008 #9
    Nikola Tesla had a 1930 Pierce Arrow which he demonstrated. The car had an electric engine and a box of vacuum tubes and antennae which pulled broadcast energy to power it. Like many of Tesla's inventions, how it was done remains a mystery. (Note, please, this is not a "water car.")

    Reading his biographies (one of which claimed he must be an alien), most of his work defied conventional wisdom. He invented the Radio, (Marconi was denied the patent - it belongs to Tesla), Alternating current, almost all the energy-generating dynamos and generators in use today, and more inventions than any inventor I've studied. Edison hated Tesla, because Tesla was the superior inventor. When Tesla won the bid to power the Chicago World's Fair with AC rather than DC, Edison refused to let Tesla used any of his light bulbs, so Tesla invented a light bulb virtually overnight that did not infringe on any of Edison's work.

    His Wardenclyffe Tower was never finished, because J.P.Morgan realized belatedly, that free energy powering transportation, lighting, and communication that did not go through any meter would not make him any money. After Westinghouse reneged on the handshake agreement to pay Tesla for his inventions, Tesla rarely drew out his inventions in any manner that could be stolen. He invented things that he never built, but after getting them straight in his mind went on to make second and third generation inventions based on his unpatented thought. Many lesser inventors and engineers backward-engineered his inventions and crafted the inventions he had perfected, taking the inventions as their own and not giving him credit.

    That Pierce Arrow would come in handy today, wouldn't it?
    Last edited: Aug 18, 2008
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