Shaun Van Poecke wrote:
I'd be really interested to know how much power peopleare using on their
boats. It neednt be too exact, though it would be nice if you had some real
Ah figures, but just generally what size of battery bank you have, what you
use on a daily basis in terms of power, and how often/how long you need to
charge for.


Im about to fit out a thunderbird 26 for cruising and its really tough to
figure out how much power and how much charging im going to need. What im
thinking is probably a single 100Ah AGM battery, a 2000watt generator hooked
up to a 30A charger. I dont really have a lot of power needs, just lighting
(flourescent), a cd player that gets used a couple of hours a day, Nav
lights, and power for my GPS/notebook as needed.

Im hoping to get 2 to 3 days use without charging.

Shaun

What follows will seem like terrible advice by some, and maybe it is.

I'd just "get into it". Get yourself some kind of a generator, some
kind of a battery, and start playing with it and see if you can get it
all to work. I'd suggest a small solar panel and a single deep cycle
battery, probably set you back about 150$us. Then just play with it.
Hook your loads up through a tiny cigarette lighter inverter from the
automobile parts store, and see how it works for you. You can even do
this at home on land if that is where you are, gain experience with the
system while using it, and then think about all of the things that are
annoying you about it. For instance, it won't take long to figure out
that a long period of overcast skies makes your solar panel charge like
crap, so you'll probably decide to get a larger battery bank (two deep
cycles, or whatever, wired in parallel) to take you the distance
between sunshiney times. Or your system might work perfect for your
needs but then after a while you figure out that you are having to keep
a very close watch on your batteries because they are losing water, so
you decide to get some kind of a charge controller to keep yourself
from overcharging the batteries. I have always felt that evolution was
the best way to create a small electrical system so that someone new to
it can actually figure out how to use a digital multi-meter, understand
the charging characteristics of your solar panels or generator, how
fast or slow it is to charge, all that fun stuff. I strong believe
that because there are simply too many variables for any newbie to
calculate, and all of the normal "calculations" come up wrong either
because the math is stupid from the beginning (so-and-so many amp hours
of batteries with a load for blah blah period of time ... right ...
tell me another one!) or because of unseen things you hadn't thought
about like voltage drops over distance, odd battery characteristics,
etc. So my vote would be to just get something and try it, if a 2000
watt generator and a battery is what you want to start with, great, do
that and see how it works for you. But plan on making changes.

In my opinion the best feature of the evolution plan is that you learn
a lot of things that could otherwise only be learned the hard way (i.e.
when it fails at sea). You end up with a very organic result that
suits you perfectly and all the things you bought early on like the
inverter that was too small, the dmm that didn't measure up, the
charger controller that didn't make enough amps, etc, all that stuff
becomes backup equipment in case of an emergency, so you really don't
lose anything and you gain a lot.

All that said, yes, I ran an electrical system with nav lights, laptop,
handheld radio, handheld gps, etc, using a Honda EU1000i generator for
about a month and it worked fine. But I had to run that generator a
lot mostly because I had a very small battery bank and was using a
charger from an automobile parts store. If I would have had a charger
big enough to use all the amps the generator was capable of and a
battery bank big enough to absorb them all it would have been a good
system, but as it was it was a lot of trouble and I always spent a day
or two doing nothing but charging up devices and batteries before I
made any passage anywhere.



....

.... or ... you could add up all the amps your devices take to run and
multiply by the amount of time you wish to run it to get the number of
amp hours and multiply that by **rolls eyes**.