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

Go to your local book store, sit down with a cup of coffee, and read a
book.

One I enjoyed was, The Voyager's Handbook:The Essential Guide to
Bluewater Crusing, Authored by Beth Leonard.

"Shaun Van Poecke" wrote in message
...
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.

40ft sail yacht, daily consumption, Mediterranean, summer:
35 to 50ah for fridge, depending on outside air temp.
40ah for nav lights over a full night watch.
20ah for autopilot going to windward, 40ah going downwind in
rough weather.
20ah for all the rest - lights at night, instruments, radio, CD

Amelioration:
Solar panel (60w) 25 - 30ah

Capacity: 600ah

Policy: discharge to 66% max (200ah)

Outcome:
Voyaging: re-charge every 48 hours with 3hr engine time, or 6hr
genny
Day sailing: motoring in and out of harbour suffices (45min a day)
Harbour time: plug into power, or run genny 1hr a day

Detail:
Engine, 100a alternator, smart charger
Genny, 240v 2kw petrol, via smart charger

Strategy:
If you're travelling by sail, you often need the engine enough to
cover all your needs. Fit an AH meter to keep track of what's
going on. The occasional discharge to 50% is acceptable, going
lower is going to affect your battery life. Even so, replacing
batteries yearly would be a damn sight cheaper than fitting and
running a diesel generator!

--
JimB
http://www.jimbaerselman.f2s.com/
Comparing cruise areas within Greece and N Spain

"Shaun Van Poecke" wrote in
:

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.



100AH isn't much of a source. You can only discharge it 50AH, if you
know what's good for it. If you discharge it further, you'll be
replacing it too often.

Whatever power you THINK you'll need is never enough. You'll soon get
bored sitting with one little flourescent light and a flashlight
listening to those same CDs all the time or the waves slapping the hull
and want more, which will drain that little battery really fast. If you
run a 2A anchor light for 15 hours, this time of year, that's 30AH of
your 50AH safe content, each day, right there. The GPS draws 1.5A,
unless it has a depth sounder, then it draws 3A times the number of hours
you're sailing. Notebooks consume their 3AH internal battery in 2 hours,
so that's 1.5A plus the inefficiency of the inverter to run its AC power
charger, let's say 2A. Sailing with GPS/notebook for nav with sonar is
about 5A times the number of hours sailing, without turning anything else
on. 10 hours sailing = 50AH drain. You'll be charging that little
battery twice a day for 3-4 hours at a time if you sail then anchor out.

Batteries charge SLOWLY. That will never change as long as we're using
inefficient lead-acid batteries, no matter how they package and hype it
or what fancy color the plastic case is. To fully charge a discharged
battery...FULLY CHARGE, not just until its voltage rises trying to stuff
50A into it at 16V to charge it in minutes instead of hours. It's a fact
of physics and chemistry, not sales and advertising. Plan on C/10 amps.
100AH/10 is 10A....for the first few hours. Then, it drops off to 5A,
3A, 1.5A after 4 or 5 hours charging from 50% drain. Jokers telling you
they can recharge their superdooper AGM in 30 minutes are dreaming. It's
STILL a lead-acid battery with lead-acid chemistry.... You have plenty
of charger, plenty of genset.

But, let's add some more heavy house batteries to extend the runtime.
That charger will standard charge 300-400AH of house battery capacity.
300AH of supply will take 600AH of battery capacity. I'd think two banks
of L16H 6V golf cart batteries will do the trick, but you could start off
with one bank and add the second one later, but not too much later. It's
not nice to parallel a new bank with one 3 years old. Two batteries in
series to get 12V then two banks in parallel to add up the AH to 660AH is
more sensible. The anchor light will run all night without draining them
dangerously low and leaving you some headroom to make breakfast in the
microwave you haven't discovered you really need, yet. To run the
notebook and microwave, get a 1000 watt Tripplite inverter and mount the
inverter right next to the house batteries through its own 100A fuse with
#4 fine stranded flexible wire from the car stereo shop (or Radio Shack).
If you open it up where the power switch is, you can parallel the tiny
power switch with a remote one with two little wires putting the inverter
control in a more convenient place. Put a neon bulb next to the switch
hooked to the AC output so you can see it's running and looks about the
right brightness. You'll only be drawing 45-50A for a few minutes as the
microwave heats breakfast. I like Tripplite because of its $70K
insurance guarantee I know is honored. They make great inverters that
don't cost an arm and a leg like "marine" inverters, which is nonsense.

Now, where you're going to put the battery boxes for these beasts is YOUR
problem. Being tall, L16H don't take up a lot of deck real estate, but
are more vertical. 100AH little AGM is not near enough. The golf cart
beasts won't cost you much more for 6 times the supply. You'll be able
to replenish their electrolyte with DISTILLED WATER ONLY, please, saving
you lots of replacement costs. They will survive an inversion as their
caps seal. Golf carts flip over, so the caps seal and have a water trap
in them. Remember you MUST LASH THEM DOWN in case the boat broaches!
Way too many battery banks are just sitting there like the boat will
never flip over. How stupid that is.....

POWER is our friend!
In the anchorage, it's not good form to be a smartass showoff and leave
all the deck lighting on for hours standing out like a beacon while your
poorly-planned neighbors with 100AH AGM batteries sit by their candles
trying to find the head with a flashlight...(c;

"JimB" wrote in news:emtjmd$725$1
@news.freedom2surf.net:

Even so, replacing
batteries yearly would be a damn sight cheaper than fitting and
running a diesel generator!


I'm not sure that's true, any mo

http://www.frybrid.com/

I bought 3 gallons of diesel to run a 6.2L GM V-8 in my stepvan service
truck last month. The rest of the fuel was free for the asking at Chinese
restaurants, who were paying to have it hauled off. 3 of us formed a
cartel we call the "French Fried Oil Company". We have fuel running out
our ears. There's 800 gallons in the warehouse as I type....(c;

Running a diesel gets cheaper and cheaper. It only takes a little time
most people don't have....yet.

I'll collect another 200 gallons Friday....(sigh)

In a 26' boat, you're really limited in your ability to increase the
size of your battery bank too far, space limitations being what they
are. I would try to get at least one more battery though. Even so, you
are going to have to be very frugal with your power usage. Therefo

- Get some LED nav lights.

- Get either an LED anchor light or one of those Davis ones (we found
most people were using the Davis ones during our recently completed 2
year cruise around the Pacific).

- For interior lighting, we found that those 110v energy saving
fluorescent ones for your house were the most efficient, even allowing
for the overhead of the inverter (there are small inverters available
that have a VERY low overhead).

- Get a battery monitor (we have the Link 10). This is a requirement,
not an option. At a glance, it will tell you not only the current state
of your batteries (How many amp hours down from full are they?, What is
the current output voltage?), but also what is happening to them at any
point in time (how rapidly are they (dis)charging?).

Even so, you are going to have to be very careful. If you can do
without refrigeration as we did, this helps a lot. Doing without a
water maker (difficult in a 26' boat) helps too.

You'll find that your computer is a real power hog. Use it sparingly.

My advice would be to get the battery monitor now, then go spend a few
days or a week at on the boat away from the dock. This will tell you
what your actual needs are far better than trying to predict them by
sitting down at a desk and adding up how much each gadget uses and how
many hours a day it will be in use.

Above all, don't get so wrapped up in the details of stuff that you
forget to have a great time.

Dan Best wrote:
In a 26' boat, you're really limited in your ability to increase the
size of your battery bank too far, space limitations being what they
are. I would try to get at least one more battery though. Even so, you
are going to have to be very frugal with your power usage. Therefo

- Get some LED nav lights.

- Get either an LED anchor light or one of those Davis ones (we found
most people were using the Davis ones during our recently completed 2
year cruise around the Pacific).

- For interior lighting, we found that those 110v energy saving
fluorescent ones for your house were the most efficient, even allowing
for the overhead of the inverter (there are small inverters available
that have a VERY low overhead).

- Get a battery monitor (we have the Link 10). This is a requirement,
not an option. At a glance, it will tell you not only the current state
of your batteries (How many amp hours down from full are they?, What is
the current output voltage?), but also what is happening to them at any
point in time (how rapidly are they (dis)charging?).

Even so, you are going to have to be very careful. If you can do
without refrigeration as we did, this helps a lot. Doing without a
water maker (difficult in a 26' boat) helps too.

You'll find that your computer is a real power hog. Use it sparingly.

My advice would be to get the battery monitor now, then go spend a few
days or a week at on the boat away from the dock. This will tell you
what your actual needs are far better than trying to predict them by
sitting down at a desk and adding up how much each gadget uses and how
many hours a day it will be in use.

Above all, don't get so wrapped up in the details of stuff that you
forget to have a great time.
Everyone's power/battery requirements are different. The first thing you
need to do is inventory all the devices that use DC. List the items and
the watts required. Then estimate the number of hours of usage for each
device per 24 hour day. Multiply the hours times the watts. Add them up.
divide the total watts by 12.5 (average dc volts), this will give you
the total amp hours per day. Double that and that is them MINIMUM size
battery bank you need.
krj

How much power is us is dependent on how many toys you have on board.
My wife and I lived on our boat for nearly ten years. During the time
at anchor we used about 165 amp/hours per day. Most of which supported
our refrigerator system (Glacier Bay). Our batteries were rated at
880 amps. We could go for about four to five days with out recharging.
We also had 130 watt Solar panels and a wind generator. Our charging
system was two 120 balmar alternators, one on each engine.
You said you are thinking about a 100Ah battery, that's not enough for
one day if you have refrigeration. A small refrigerator will consume
50-60 Amp/hours in a day. Your batteries should never fall below 50
percent of their rated value.

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**.

On 28 Dec 2006 08:34:38 -0800, "purple_stars"
wrote:

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.

Which pretty well summarizes most of the advice that others have
offered:

- a single 100 Amp-Hour battery is not big enough because: 1) It will
not supply enough power to be useful; and 2) It will not accept
recharge current at a high enough rate to recharge quickly.

I have found 440 Amp-Hours to be sufficient for moderate loads over 24
hours: Small refrigerator; some computer and entertainment devices;
navigation equipment; lighting - average total draw between 5 and 10
amps.

440 Amp-Hour capacity can be easily and inexpensively obtained with
(4) 6 volt golf cart batteries in series-parallel. Price is in the
range of $50 to $60 each if you shop around, and they weigh about 60
pounds apiece. If you are careful to avoid discharging below the 50%
level (about 11.6 volts under load), they should be good for 300 to
500 discharge/recharge cycles. A 440 A-H battery bank can be
recharged at a rate of 100 amps up to about the 80% capacity level.