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Re: [Marxism] Electric Cars

Here we go again, comrades....
There are some facts to consider re. electric cars, busses, and the alternatives.
First on the small internal combustion engine. I take as an example a 30 hp marine diesel of ancient vintage designed to run at 2500 rpm ±10% manufactured for the last 30 years by Yanmar, a Japanese company. Running at 2500 rpm at its maximum output, this engine produces 18.5 KW and consumes 0.63 gal/hr (±6%) of diesel fuel, which has a thermal equivalent (i.e., burned completely) of 135,000 BTU/gal. Arithmetic now shows that the engine burns the equal of 85,500 BTU of fuel per hour with an energy potential of 24.8 KW. Since the useful power is 18.5 KW (i.e., all friction, waste heat, etc. is not included as "useful"), the efficiency is 18.5 / 24.8 = 75%.

Electric motors can be made with almost as high an efficiency as you want, but the weight and material costs begin to skyrocket above 92 - 93%. So the power lost by the cited internal combustion engine is 3 times greater than the modern electric motor. But...

Batteries: A lithium-metal-hydride battery cell (if the ones I have are representative) charges at 1.42 volts and delivers most of its charge at 1.25 volts. This is 88%, a very good number for any battery. Nevertheless, efficiency of the battery-motor combination is 81%. One can get a lot of power from a battery in a hurry, but the losses go up as the *square* of the rate of power draw. The same holds for the losses during charging. Since I don't yet have at hand cells designed for very rapid charge and discharge rates, I can't testify as to their efficiency but I can say they are not likely to be better than the 88% I've measured. (The batteries I have measured are designed to charge at a rate of 50% of their ampere-hour capacity. I.e., a 200 Ahr battery is to be recharged at a 100 amp rate.) The aim of current research is to increase battery capacity (stored ampere-hours) relative to their weight, bulk and cost. Increasing their charge rate is subject to the *square* law of diminishing returns and not much improvement is expected if efficiencies are maintained.

Delivering electric power to the customer is woefully inefficient except for major users like metal smelting and refining. The "power grid" is barely operable, to say nothing of its efficiency. For the last century, the engineers have been asked to minimize the capital cost of power distribution first, maintenance second and reliability third, and efficiency is down, down the list. For example, the current power distribution transformers are efficient only because they cannot be made less efficient and be kept from burning up. And so forth. Delivering power from Hoover Dam to Los Angeles or from Niagra Falls to New York City is a disaster from an efficiency standpoint. Off the top of my head, I'd say the efficiencies fall below 80%, and again, the losses increase as the *square* of the demand rate. As an aside, one advantage to nuclear power could be (possibly, perhaps, maybe) the short distance between generator and consumer. Assuming that car batteries are charged at off-peak hours (to minimize that nagging square law loss), we would be fortunate to get a fuel-to-horse power efficiency of 65%. This number - 10% below the naked diesel - should not discourage us, but rather get our heads out of the clouds.

100 million efficient electric cars would present a technological challenge to a socialist America, to say nothing of the beserk capitalist state we have. There are many challenges besides the transport of individuals that might occupy us first.

Please: notice of any errors or omissions should be sent on or off line to me pronto.
thanks,
--rod



Anthony Boynton wrote:

In regard to David Walter's post, and I guess an
earlier discussion, there is a lot going on with
electric cars, beyond the Telsa (the silicon valley
luxury electric sports car David mentioned.)

I suggest readers check out ZAP and Obvio. ZAP is an
electric car distributor in California which has been
importing cars to the USA from China. The cars are
very small, very slow, and have a short range. Now ZAP
has invested in a Brazilian company, OBVIO which plans
to produce a much faster car, with greater range, and
significantly reduced charging times. ZAP has signed a
contract to buy 50,000 of these cars and import them
into the USA.

Brazil and China both have government supported R&D
programs to develop alternative fuel cars, and have
put significant resources into electric car
development.

Electric cars, even with lead acid batteries, are
definitely more environmentally friendly than are any
fossil fuel burning vehicles.

In the first place, current electric motor technolgy
is 2-3 trimes more eneregy efficient than internal
combustion engines.

In the second place electricity can be generated
without burning fossil fuels, and without burning any
carbon: wind, tidal, geothermal, hydroelectric, solar
and nuclear are all possible. (All have their
environmental prices, but none emit CO2 into the
atmosphere.)

In the third place even thermal generation burning
fossil fuels in a large plant is cleaner than burning
fossil fuels in millions of small engines. There are
economies of scale which include the possiblity of
burning at higher temperatures, for more complete
combustion, and investing in very expensive
technololgy to clean the "exhaust".

As David said, rapid advances in battery technology
are the key to advances in electric car development.
This is not just because of environmental issues, but
because of practical issues. Lead acid batteries are
very heavy, must be recharged freqently, and take
hours to recharge.

To power a small four door sedan converted from
interanl combustion to electric power requires between
12 and 20 standard 12 volt lead acid car batteries.
The range of such a car between recharging will be
anwywehre between 60 and 200 miles, its maximum speed
is likely to be less than 60 mph (depending on
design), and it could take up to 8 hours to recharge
the batteries (depening ont he system used).

Converting internal combustion cars to electric is a
growing trend, with more than 100,000 such vehicles no
the road in the USA and Canada.

The guy who is the key player at Tesla has been
promoting this trend for years. In fact, they even
have electric drag racers, which accelearate up to 200
mph on short runs.

Right now I have an old Mazda 323 sitting in my garage
waiting for me to get enough money to buy the rest of
the parts to convert it into Colombia's first electric
car.

All the best, Anthony






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