alt.energy.renewable

>
>
>sallows.roy@gmail.com wrote:
>
>> What would happen if you hooked a fractional horsepower motor to a
>> automobile generator, and fed the power into a bank of 12V deep-cycle
>> batteries?
>
>You'd waste a LOT of power for no good reason. Use the electricity
>directly to charge the batteries.
>
>Graham

Graham, I took "fractional horsepower motor" to mean a gasoline engine, since he spoke of
sourcing one from a weed whacker or rototiller. Basically, he is describing a home-built
series hybrid, with a small gas engine as the prime mover.

Roy, You could do something of that nature, but I believe it would be a mistake to run the
system on 12 volts. A large-capacity car alternator puts out about 80 amps at a nominal 14
volts, so that's only a little over a kilowatt of useful electrical power. If I were going
to do something like that, I'd design around 100-120 volts. That way I could use a
commonplace AC genset to provide my road power. Maybe a Honda EU series. They are nice and
quiet, and run only fast enough to meet the load placed upon them. With higher battery
voltage, you can use lighter-gauge (and lighter-weight) wire and switchgear. Also, there
is much more choice in motors out there.

I'd go with 4 wheels, UNLESS you live in a jurisdiction that licenses 3-wheelers as a
motorcycle, and gives a tax/traffic advantage to them. If you can run in the HOV lane with
a motorcycle, for example, that might be worthwhile. Or if "motorcycles" get a break on
"congestion charges" going into the city.

I'd also consider giving the car enough of a battery bank to complete one commute cycle
with a little reserve. Then you could dispense with the generator for short hops, and just
charge off the mains. Put the generator on a little trailer, and hitch it on when making a
longer journey. That way, you are not constantly toting the mass of the generator when it
is not truly needed, so operating economy will be better than if you did.

I'd also not worry too much about exotic materials and construction techniques in an
effort to save weight. Fine, if you are out to break some kind of record, but for a real
car that you can really use, I think you'd be better off simply purchasing a small, light
car, and converting it. You'll be on the road much more quickly, and the finished product
will look like a real car, instead of a toy.

Gordon Richmond