just_passing@ burntmail.com wrote:

Just Tap off from 2 - 12 volt batteries easiest.
Then you split your load between both. - plus you still have 24 volts
as well.
But you still don't gain - as in energy input must still equal work
output - So amps * volts = watts so you still need the motor hp's to
turn it over. So if you don't need it, its overkill.

There are DC/DC converters to draw 12V from a 24V battery bank but
tapping off of half of a battery bank is not a particularly good idea.
You end up with unequal discharge unless you pay a lot of attention to
juggling loads. Routine recharging of unequally discharged batteries as
one bank will shorten their service life.

What you gain with a brushless is efficiency, lower charging RPM and
reliability. In general, you will burn less fuel to generate a given
amount of amp hours with a brushless than with a regular type
alternator. Their power curves are steeper and start leveling out at
lower RPM. With no brushes, springs etc, the only things that can wear
out are the bearings and Niehoff and Electrodyne oversize those to the
point of excess. They are also electricly quieter. With no brushes
there is no spark and therefore less noise for your radios to contend
with.

The only down side is that they cost to much. Well maybe not compared
to what balmar charges. West marine wants $1,800 for a Balmar 96-275.
You can get the equivelent output from an Electrodyne GEB200 for about
$1,200. You might wonder about a 275 amp alternator being equal to a
200 amp one but the Balmar is COLD rated 275 amps at 6,000 RPM and the
Electrodyne is HOT rated 200 amps at 2,700.)

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com