Electric Cars

I have watched with some interest the dispute between the New York Times and Tesla Motors, or respectively the reporter who test-drove Tesla’s model S electric car and Tesla’s CEO, Elon Musk. The report on the test drive was damaging to Tesla, inasmuch as it ended up with a picture of the immobile car on a flatbed.

The real problem, IMO, is that the battery-only strategy of the Tesla is not a good engineering solution, given the current state of battery technology, and Tesla is on the defensive as a result. Tesla has attempted to address the problem by populating the US with special charging stations, which apparently can recover the battery to full charge in about an hour after each leg of up to 200 miles. But even with this support, charging adds substantially to driving time on long trips, between extra miles driven to the charging stations and time spent there charging. It also means that the driver must be very conscious of “fuel” management and plan his route like a pilot flying from airport to airport.

I lease a Chevy Volt which has a much shorter battery range than the Tesla (typically in the low 40s) but, unlike the Tesla, has a small gas engine called the “Range Extender” in addition to its battery. This engine removes any anxiety about running out of battery energy, and avoids long inconvenient delays for charging.  It does not recharge the battery, but instead cuts in and out to maintain a minimum charge. Recharging only occurs from utility power, which is intended to be the primary source of energy to operate the car. I have had the Volt for four months and over 4000 miles. I still have not purchased any gas for the car, other than the full tank with which it left the dealership when it was new. I have used a tad less than four gallons of it, about half the tank. Of course this outcome depends on my usage pattern, which is primarily short urban trips. But if I choose to take a long trip, no planning is involved, I just stop at gas stations as necessary.

The Tesla is a more “elegant” solution and uses zero gasoline. But the Volt’s consumption in my hands of less than a gallon every 1000 miles is close enough for me. Yes, I have to carry around what is, in effect, a small genset but, even so, the Volt weighs nearly a thousand pounds less than the Tesla. If the idea is to switch from gasoline to utility power as the primary energy source for the car, the Volt accomplishes that. I guess it fails if ideological purity requires utility power as the sole source. As an engineer, I’m interested in practical solutions and on that basis the Volt wins hands down over the Tesla. I don’t think GM is getting the credit it deserves.

All of the above is my opinion based on the information available to me. Correction of any factual errors is invited.

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Comments

  • ..  On February 20, 2013 at 6:18 am

    The Volt is very clever. For example, it automatically heats the seats on cold days. The theory being that passengers with warm bottoms use less heating and less energy.

    It also automatically uses the “Range Extender” motor from time to time just to keep it in good working condition and to use up the gas as it get old. Lots of thought went into small details that make the most of the energy it does have.

    This isn’t my father’s Chevrolet. He was an engineer and he would have loved the Volt!

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