On Sat, 22 Mar 2008 06:15:07 -0400, "Roger Long"
wrote:

A good diesel mechanic up here told me the first question he asks
when a sailboat owner says they are having trouble with their diesel is, "Do
you have refrigeration?" Unless they have a separate generator, he knows
right where to start looking for the problem.

Why is that? Too much time at idle to charge batteries? If so, they
need a bigger alternator and/or larger battery bank.

On Mar 21, 4:37 pm, Richard Kollmann
wrote:
It is interesting to know how other boaters are selecting equipment
and managing electrical power on cruising sailboats. Standard
production sailboats rarely have onboard DC power grids to support
additional electrical loads. Most extended cruisers and live aboard
boaters prefer to have conveniences like refrigeration microwave
ovens, computers and creature comfort items. There must be a limit to
how much daily electrical load that can be supported on a pleasure
size extended cruising sailboat, but what is this limit? I believe
that an average cruising boat's DC power consumption when at anchor
might be at least 50 amp-hrs per day. If equipped with refrigerator
add 10 amp-hours per cu. ft. of box per day. If additional 110 volt
appliances are powered from an inverter the total power grid will be
overstressed unless energy is generated from other than the a engine
alternator.
(clip)

If you are following Skip's Morgan 46 adventures on Flying Pig you
know his plan was to support all his electrical and refrigeration
needs including heating water with 12 volt energy. Skip removed the
engine driven refrigeration system replaced it with a 12 volt
Frigoboat unit. The large generator was removed providing room for a
battery bank. We are still not sure what his actual daily power needs
are but he seems to be managing his energy budget by trimming down the
load and running a small Honda generator when wind and solar power is
not enough. One good piece of information Skip provided if I
understand him correctly is the Hondo 2000 powering a 40 amp DC output
charger can rum 6 hours on 1/2 gallon of gas. I have a 3000 watt
generator that consumes 6 gallons per hour.

Hi, Guys,

Larry's observations about my genset are accurate. I don't know where
you got my consumption figures, Richard, as I thought I'd indicated
that my typical run was ~6 hours per tank when charging and doing
other miscellaneous stuff. That's vs, for example, heating the hot
water tank, which I would never ask the inverter to do, a full-
throttle run, but only for about 15 minutes of the time in a recharge
cycle. The normal recharging run has all the "normal" inverter (no
mikey, no heat gun, no hair dryer) items like computers, handheld and
"dry cell-type" battery recharging, etc., at the same time as
recharging the house; the water heater is typically reheated at the
same time, but the charger turned off for that period.

OTOH, if we forget to turn off the charger, the combined loads is more
than the Honda can handle, and the overload kicks it off. That is, no
power is delivered; the engine continues to idle. The cure is to
cycle the on-off handle until the red light goes out and turn it back
to "on" where it kicks in again. So far, we're very happy with it. It
and the dedicated fuel can live in the cockpit, under Sunbrella
covers, and right next to the scupper drain in the event of leak or
fumes, in a space which might well have been designed for it, the
fit's so good :{))

Meanwhile, I've been wondering if you have some easy, inexpensive,
means of actually tracking the AH usage, both for the reefer and as a
whole. The TriMetric may have such a function overall, but I don't
really know how to separate it on a daily or timed-period basis, and,
of course, not for the reefer. It would also be interesting, but not
something I think I need to have on a permanent basis, to know the
number of cycles the reefer compressor has per day. Ideas on all
that?

Finally, because of the above, I really don't have hard numbers on the
usage, but the individual loads were carefully measured (or as
carefully as a nothing-else-running measure with the decimal amps
readout of the TriMetric) per device, so I'm pretty confident in the
numbers I presented, and in the time of usage per device. If I'm
reasonably accurate in those, the AH daily use should be pretty close.

For all that, as noted, in sunny and breezy conditions, we are fully
supplied for our usage. So far, the Honda supplement has proven
acceptable, though I'd far rather not have to use it other than for my
Hookah rig or other high demand tool-style times. Certainly, though,
offsetting that, I don't believe I want to run 1500 watts for even 15
minutes from the inverter - unless it's blazing and howling outside! :
{)) - to make hot water, so, for passages, it appears we'll be using
that at least occasionally.

Thanks for any pointers to gear for measurement...

L8R

Skip

Morgan 461 #2
SV Flying Pig KI4MPC
See our galleries at www.justpickone.org/skip/gallery !
Follow us at http://groups.yahoo.com/group/TheFlyingPigLog
and/or http://groups.google.com/group/flyingpiglog

"You are never given a wish without also being given the power to
make it come true. You may have to work for it however."
(and)
"There is no such thing as a problem without a gift for you in its
hands. You seek problems because you need their gifts."
(Richard Bach, in The Reluctant Messiah)

On Sat, 22 Mar 2008 09:19:58 -0400, "Roger Long"
wrote:

With a small engine like mine and modest electric loads otherwise, wouldn't
it me more efficient to put the largest compressor that a toothed belt pully
and engine PTO limitations would permit on the front end of the engine?
Then have a large cold plate in the box and draw it down as quickly as
possible keeping the engine under maximum load. It wouldn't give you the
fine temperature control of a constantly running 12 V. fridge system but
would be as good as ice. Drawing down the cold plate would be like buying
ice (and probably nearly as expensive at next year's fuel costs).

The conversion from fuel to electricity to charging and back to motive force
has got to use up more fuel than just running the compressor directly.

Most of the boats I see here use exactly that system. The more
up-market ones have a duel system with both engine driven and A.C.
powered compressors for use at sea and in the marina.

If you really want to get into it find a copy of Nigel Calder's book
on refrigeration systems (he is a fellow Mainiac. It is down to earth
and really teaches you how to build a system.


Bruce-in-Bangkok
(correct email address for reply)

Bob wrote in news:b6e6457e-43de-4228-9e7f-
:

but the genset is tooo noise for my
guests..... So.



That's a FEATURE not a problem....(c;

"Roger Long" wrote in
:

"Jere Lull" wrote

When we're on Xan, we are connected only as we wish.


That's the biggest reason I would like to install refrigeration, to be
a bit less connected to the shore for cold stuff.

You're right about the cost though and it isn't just the installation
and fuel. A good diesel mechanic up here told me the first question
he asks when a sailboat owner says they are having trouble with their
diesel is, "Do you have refrigeration?" Unless they have a separate
generator, he knows right where to start looking for the problem.

--
Roger Long





While we're talking fridges and power requirements, I'd like to describe
a 2.2 cu ft dorm fridge I bought a few years ago for a pittance at a
thrift shop, probably $10. It's seen hard dorm use. I replaced the
door gasket and repaired the plastic inside the door. It's a Norcold,
but I can't find any model plate, sorry.

What's neat about this little fridge is in the back....it's compressor.

Wrapped around the back of the fridge is a rather large, for its size,
condensor that is stood off the fridge so it doesn't heat the
case....you know...like the NEW fridges do...which is stupid. Between
this wrap-around condensor and the rear wall of the fridge is a steel
cylinder about 3" in diameter and 9" long sitting vertically. ONE wire
comes out of it and the steel case is the other conductor. This doesn't
matter because it runs on 40 VAC 50-60 Hz. The compressor gets this
voltage from a little transformer that is specific to the country
they're shipping the unit to. In our case, the transformer is 120VAC to
40VAC. In Europe they use the same compressor, just a 240VAC
transformer.....very logical.

This odd little compressor is not a motor at all! It's a solenoid
driving a single cylinder little pump. The AC makes the plunger in it
vibrate back and forth at 60 Hz, which is also the piston in the
pump...only ONE moving part! I suppose it has reed valves.

We'd not be allowed to build these, today...It uses R12 refridgerant
because R12 is the most efficient and lowest pressure, the reason they
used it for decades in cars before the Algores drove us crazy with the
lie of Global Warming caused by AMERICAN FREON, which was BS to raise
the price of freon from 60c/pound to $10/pound...another story
altogether. The Antarctic ozone hole is LARGER, now that we have
stopped the production of Freon 12, obviously not reported to an irate
nation, because it has nothing to do with it.

Now, using R12 low pressure refridgerant and this little plunger pump is
MOST impressive for use in a vehicle or boat! IT ONLY DRAWS 40 WATTS
WHEN IT'S RUNNING! To use it in the car on a trip, I plug it into a
tiny inverter from Radio Shack rated at 75 watts, built right into the
cigarette lighter plug. I'd bet the whole thing draws 42 watts ONLY
WHEN IT'S RUNNING, which, of course, depends on how much beer it's
cooling and how many times the door opens. there's room in its
"freezer", inside the evaporator sheet metal with a little door, for 2
trays of ice cubes and it will make ice in about 90 minutes. It will
also keep ice cream sandwiches frozen hard packed in there, too.

My calc shows this to be about 3A at 13.8VDC. If it ran wide open,
which it doesn't or we'd have frozen beer in a day, that's only 72AH in
24 hours. It's probably about 60% of that or 43AH per day.....which is
MUCH BETTER than a portable absorption fridge for the car which uses 4A
continuously and doesn't cool worth a damn.....

These fridges, if you are perusing thrift shops, are easy to spot. The
evaporator and beer-can-shaped cylindrical compressors stick out the
back because the compressor must be vertical, not horizontal, in
operation. This shape distinguishes it from the power hog motor
compressors that are squat and fat in most fridges.

It really does keep the beer COLD....for just a little power.....

"Roger Long" wrote in
:

I think adjusting my life style and diet on long cruises may be a
better option. I'm going north where I won't miss cold stuff as much
as I would going south.



Where you live I think what you need is a cold box against the hull so you
can route frigid seawater through a coil of stainless pipes inside the box
with a simple scoop on the hull, underwater, pointed forward to catch the
water going by. Just aft of the scoop, in the trailing low pressure zone,
warmed water from the "fridge" would be released back into the sea,
unnoticed by the greenies fearing it would warm the ocean.

Except for 3 days in August, as I remember swimming in Maine, our problem
would be to keep the beer from freezing solid.

Make the box large with large cooling pipes all the way around the inside
of it. Surplus copper tubing with a zinc pencil would last your lifetime.

I'm from the Finger Lakes of upstate NY. Cold beer there just means
hanging the sixpack off the stern on a line hanging down during the
fishing. Because we'd come back with no beer, the same line can be used as
a fish stringer if the damned fish were biting....(c;

On Sat, 22 Mar 2008 09:19:58 -0400, "Roger Long"
wrote:

The conversion from fuel to electricity to charging and back to motive force
has got to use up more fuel than just running the compressor directly.

That's true if your only requirement is refrigeration. Since I'm a
bit of an electrical junkie I'd probably opt for the big alternator if
I only had room for one or the other. It is possible to get high
output alternators in a small frame however. I have a pair of them on
my boat which are no bigger than the originals.

http://tinyurl.com/249bwl

or

http://tinyurl.com/ynr2l5

"Roger Long" wrote in
:

The conversion from fuel to electricity to charging and back to motive
force has got to use up more fuel than just running the compressor
directly.



It does. They need to power the pulley on the compressor from a pulley on
the POWER PLANT, not the propulsion engine....

"Roger Long" wrote in
:

One of the damndest things I ever saw in a museum was something called
a Shaker refrigerator. It was an insulated box with a slot in the
side. There were two metal balls, about the size of small soccer balls
made of what looked like zinc or galvanized steel with a pipe soldered
on connecting them at the top and separating the balls by about 18".
You put one of the balls in the fire and heated it up to nearly red
hot. After it cooled, you put that ball in the refirgerator and ice
formed on it for about 12 hours. Then, you took it out and put the
other ball in the fire, cooled it, and put it back in the box the
other way round.

I think the balls were filled with ammonia. I suppose you could make
one of these work by putting the ball in the BBQ grill over the
transom.

Clever people those Shakers. Shows how much mental energy is left
over when you aren't spending 18 hours a day trying to get into your
neighbor's wife

--
Roger Long





That's the Absorption Cycle. Go look how any RV refridgerator operates.
The freezing comes because Ammonia just LOVES water. When Ammonia
combines with water heat is absorbed. The gas burner (or electric
heater when the RV is plugged into the park) merely boils off the water
and ammonia to separate them so the cycle can repeat...simply by gravity
flow. There's no pump needed....just heat. I know someone with a
kerosene refridgerator that runs on a kerosene wick lamp. The lamp
heats the boiler, instead of a propane flame. It was a really old
fridge, probably of historic value.

UNfortunately, for sailors, this fridge needs to be LEVEL to operate
properly because it is a gravity-flow device. If the RV is tilted just
a couple of degrees off level...the fridge just stops. They also
sometimes become vapor locked by water being in the wrong place. The
solution to that is also quite simple. Remove the fridge from the
camper, turn it upside down and leave it that way overnight. Flip it
back over and reinstall and it works fine, again. I think this kind of
fridge would be fine if gimbal mounted. They cool just fine in a MOVING
motorhome roaring down the interstate using its 12V heating coil to save
propane. I had a big Dometic refridgerator-freezer in my last motorhome
that would do any sailboat proud. It ran off of 115VAC, 12VDC or
propane, your choice. It would run just as well off an alcohol flame to
keep the fumes out of the bilge. The gimbal mount would level it so it
would work while the boat was heeled over by the sails.

That was a Crosley Icyball refrigerator. A bit more complicated to use than
that. It was an absorption cycle device that you had to recycle manually
every morning. It had a little kerosene burner that kept the hot end
working.

--
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

"Roger Long" wrote in message
...
One of the damndest things I ever saw in a museum was something called a
Shaker refrigerator. It was an insulated box with a slot in the side.
There were two metal balls, about the size of small soccer balls made of
what looked like zinc or galvanized steel with a pipe soldered on
connecting them at the top and separating the balls by about 18". You
put one of the balls in the fire and heated it up to nearly red hot.
After it cooled, you put that ball in the refirgerator and ice formed on
it for about 12 hours. Then, you took it out and put the other ball in the
fire, cooled it, and put it back in the box the other way round.

I think the balls were filled with ammonia. I suppose you could make one
of these work by putting the ball in the BBQ grill over the transom.

Clever people those Shakers. Shows how much mental energy is left over
when you aren't spending 18 hours a day trying to get into your neighbor's
wife

--
Roger Long