alt.energy.renewable

On Mar 6, 3:57 pm, "Ray King" wrote:
> Todd,
>
> It works for you but to get up to 14 volts you have wasted about 30 watts
> before you begin to push current into your batteries.

Big deal. I'm wasting far more than that in heat off the tiny 4KW
diesel. This system was initially required as a backup on cloudy days
for my PV system. However, its cost is about 1/5 that of one PV panel
and puts out more than 10 times the charging power. I will admit that
it is more hassle than the PV source but it is a better alternative
than expanding the PV source and battery bank. The use of free waste
vegetable oil (WVO) makes it so.


> The auto alternator is
> designed to push 100amps or so at 3000 rpm.

I run my diesel at about 1000 rpm. I figure it will last longer at
that speed even though it's not the peak efficiency point on the
torque curve.

> It takes 3 amps to generate the
> amplification factor for 100amps or 100/3 = 33.

I put in 2W and get out 240W with my current settings. That's an
amplification factor of more than 100.

> If you rewind the field with
> smaller wire to double the amp turns you could not get the amplification
> factor to 66 or even higher. A better way ( if you only need a few amps ) is
> to run the negative output of the alternator ( grounded to the fields
> negative out put ) back through the field so that the output current is
> feeding the field in series. this looses very little energy but you do not
> loose the field power.

I'm not turning the alternator with wind or water, thus driving for
such efficiencies is sort of ridiculous in my case.

> This is easy just float the alternator from ground
> and disconnect any regulators and take the positive output from the
> alternator from the normal positive output and the negative output is the +
> field connection. When you exceed 3 amps you should rewind the field with
> larger wire and fewer turns. This can increase the alt output to the limit
> of the field brushes. You may have to flash the field if you bang the field
> frame and it looses its magnetism.


All very interesting, but the total cost of my solution is $10 (the
junk alternator). I'm quite satisfied to leave it at that and get on
to other things.

/T