Skip Gundlach wrote in
ps.com:

On Jul 26, 11:49 pm, Wayne.B wrote:
On Thu, 26 Jul 2007 01:51:23 -0000, Skip Gundlach

wrote:
We've already got massive batteries. The issue is properly keeping
them charged. At 750 nominal (less aging) AH, we can go for a long
time with no charge input. But if we don't put in the charge,
eventually the biggest battery bank will be flat, even if nothing is
drawn from it, out of normal charge dissapation (flooded = ?%/
month)...

To recharge 750 AH in a reasonable length of time you need a 3 stage
charging source of 150 to 200 amps (25% of capacity). Don't let
Larry
tell you anything different. Wiring of appropriate size is also
required of course.

If you had a generator you could do that the way we do - use the
charger half of a high powered inverter/charger. Since you don't,
you
will need a seriously high powered alternator with an external
regulator. An alternator of 200 amp capacity will typically be a
large frame Leece-Neville, require two drive belts, and quite
possibly
some custom work on your engine drive sheaves and alternator mount.
All of this is not cheap of course, and it will take some shopping
around just to find someone qualified to do the work. Nothing less
is
going to get the job done however.

I'm obviously missing a great deal of intelligence here.

I had thought we'd properly sized our bank and input sources to allow
for our anticipated usages.

Obviously I was mistaken; I need a large-frame alternator and the
appropriate drive components, in order to only bring my bank to 90%.

Instead, I'm inputting, over an entire day, unless they're already
full, in which case the controllers either divert or disconnect the
load, on average, somewhere between 150 and 300AH, an average (varies,
of course) of 6-12A per hour. Obviously, that's inadequate to keep a
battery topped up, especially a big one.

Trickling it in, I'd expected to rarely stress my batteries, rather
than subjecting it to high inputs for short times, and to, for the
most part, keep them full. I see I'm mistaken and must put not less
than 100A into the battery bank any time I'm charging, and must make
time in my schedule to run the main engine at least often, if not
regularly.

My 370W of solar, and KISS wind generator, are taking waaaay too much
room on the arch considering they're doing nothing to enhance my
charging regime. I figure I can save at least 100 pounds off the load
on the stern if I ditch them. Where I am, right now, in Charleston SC,
at 9AM, I'm only making 10 solar Amps with a bank which reads 13.9.
Yesterday, at 5:30, when I turned off the outside power and fired up
the inverter and put everything I could find on the load, it only was
making 20A. Controllers apparently size the output to the load (?).
I wonder what it would do at noon with a load?

I have no idea what it will do in real-world situations. I've only
seen 25A at the dock, sometimes, and 30A from the wind, but today's
dead calm, so there's nothing there.

Perhaps I'll just have to learn to live on less than 200AH/day, and
buy one of those massive alternators.

You had better learn to live on 200 AH or less if you're going to stay
on a hook! You can have the biggest battery bank around, but if you
can't keep them charged, they won't do you any good. I'd rather have a
much smaller bank that I keep charged rather than a huge bank that's
undercharged.

Solar panels are great if you're somewhere that has lots of sun. I
personally de-rate the panels to 1/2 of their listed wattage to come up
with the *maximum* that I'll see out of them. This is 11 AM - 1 PM sun
and then it falls off before/after that. As the batteries climb in
voltage, you'll see less and less wattage.

Wind is great if you're somewhere that's windy. Summer on the dock in
Charleston doesn't fit that bill. The Bahamas or Caribbean quite often
does. I personally would rather spend $ on wind generators rather than
solar as I feel that you get a better bang for the buck. The wind can
blow for 24 hours, but at best you get 6 hours of good solar generation
without sun-following panels.

On BlueJacket we use about 150-200 AH a day. Refrigeration takes up the
bulk of that at about 85 AH. Replacing all of our incandescent lights
with LED based lights really helped save power. The rest of the power
goes into stuff like making water (about 40 AH), running the computer to
get weather faxes, stereo, watching DVDs on the TV, etc.

Whatever power I don't generate via my solar panels or wind generator, I
make up via the generator powered ProSine inverter/charger. (Note that
I wouldn't recommend ProSine as I've had to replace the unit too many
times.) I don't want to run the engine to charge the batteries as I
don't like to run the engine under light loads and I like to reserve
engine hours to moving the boat.

So you're right where most cruisers are when they find out that they're
power hungry and their generation doesn't match their consumption. The
easiest thing to do is to cut back on the usage, but that only goes so
far. Good luck balancing things. It takes a while to figure it all
out.

-- Geoff
www.GeoffSchultz.org