"misia" wrote in message
ail.from.there...
On my new boat I will have a powerfull 24VDC battery bank charged by a
diesel generator and auxiliary sources.

How powerful? Are you talking about a thousand amp-hours, or a hundred
thousand amp-hours? I can't imagin the cost, hassle and space rewquired for
the latter, but it is what you would need to provide what you are asking
about.


I did a bit of search but couldn't find much- are there any 24 VDC
appliances such as cooker/oven, fridge, AC and water heater you could
recommend?

In general, it is impracticle to use battery power for creating heat, i.e.,
stoves, ovens, water heaters, etc. It simply takes too much power for too
long to make it practical to store. Nevermind the voltage, it is more of an
issue of watt-hours.


I know I can run standard items through power inverter but I would
prefer not to do it for the sake of reliability/efficiency/cost.

Using the inverter, you have the reliability and cost of just one thing: the
inverter. After that, you can use very reliable and low cost 110 volt AC
appliances. To find 24 volt anything is going to be expensive, and the
bottom line is that DC motors are just not as reliable as AC motors, and
high current/low voltage is harder to work with (and thus less reliable)
than higher voltage/lower current.

I want
to go totally electric (no gas)

Then run your generator when you need the power, and use the batteries for
the small stuff.

A reasonable battery bank can run your lights, refrigerator, and through an
inverter you can run small appliances (such as a blender or short use of the
microwave), TV, stereo, computers, etc.

When looking for 24 volt equipment, take a look at commercial and "mega
yacht" sources. Lights shouldn't be a problem, but you may find that
electronics are scarce and very expensive. Since your battery bank is most
likely made up of a number of batteries in series, you could tap off a 12
volt line and have both a 12 volt and 24 volt system. Use the 24 volts for
the higher wattage stuff, such as the inverter, windlass and lights. Use
the 12 volts for the electronics, such as depth finders, VHF, etc.

Run the stove, water heater, and air conditioning off the generator.


Rod McInnis

"Larry W4CSC" wrote in message
...


I've never figured out why boats in cold climates waste all this
energy going out the exhaust. It's SO easy to make a cast iron heat
exchanger in a dry stack, right next to...or even right IN the exhaust
manifold that will just roast your ears with free heat.

the old Volkswagon Beetles used a heat exchanger off the exhaust manifolds
to heat the car! It was actually pretty nice on cold mornings, as the
heater worked almost instantly after starting the car.



We retrieve some of it with the hot water heater hooked to the water
jacket. Too bad so much heat is simply wasted.


There is a lot of free heat to be had from the engine. The only drawback is
that the engine has to be running! Not what you want when you are swinging
on the hook!

Rod McInnis

Rod McInnis wrote:

When looking for 24 volt equipment, take a look at commercial and "mega
yacht" sources. Lights shouldn't be a problem, but you may find that
electronics are scarce and very expensive.

Most newbuild megayachts are equipped with very
comprehensive AC electrical generation, regulation, and
distribution systems.

The last large (165') yacht I sailed on was wired like most
of its class and used a wheelhouse mounted bank of batteries
to supply the electronics. That bank was float charged by a
charger mounted in the battery room. No one is going to run
DC supplies from a central location on a larger boat.
Depending on the certification standards a local emergency
supply is required in any event.

While I have not bothered to search, the selection of marine
equipment available in 24VDC must be very very small. Most
all little boats use 12VDC, most larger boats use
110/220/480VAC.

There used to be a pretty good selection of 32VDC stuff but
even then most heating was provided by burning fuel
directly. It strikes me as absurd to run a heating or
cooking system on DC unless it comes straight from a DC
generator and even then, nowadays, why bother.

There are several diesel fired heating boilers available for
hydronic heating that can be supplanted with waste heat when
the main propulsion is online or a genset when it's not.

The megayacht industry has developed some outstanding power
management systems but none of them include low voltage DC
for heating or cooking. It just isn't practical, even in
larger scale, and certainly not when you have to burn diesel
in a generator to charge a battery to supply an inverter to
heat a resistance coil to make heat.

Rick

Dear Rod,

I hear you. I absolutely agree on everything you said. The battery bank would be
15kWh capable AGM (for 100%50% discharge). There will be a 12V battery with
24V12V crosscharger.

I have found 90% efficient 5kW inverters in Taiwan for approx $600. M

Rod McInnis wrote:

"misia" wrote in message
ail.from.there...
On my new boat I will have a powerfull 24VDC battery bank charged by a
diesel generator and auxiliary sources.

How powerful? Are you talking about a thousand amp-hours, or a hundred
thousand amp-hours? I can't imagin the cost, hassle and space rewquired for
the latter, but it is what you would need to provide what you are asking
about.

I did a bit of search but couldn't find much- are there any 24 VDC
appliances such as cooker/oven, fridge, AC and water heater you could
recommend?

In general, it is impracticle to use battery power for creating heat, i.e.,
stoves, ovens, water heaters, etc. It simply takes too much power for too
long to make it practical to store. Nevermind the voltage, it is more of an
issue of watt-hours.

I know I can run standard items through power inverter but I would
prefer not to do it for the sake of reliability/efficiency/cost.

Using the inverter, you have the reliability and cost of just one thing: the
inverter. After that, you can use very reliable and low cost 110 volt AC
appliances. To find 24 volt anything is going to be expensive, and the
bottom line is that DC motors are just not as reliable as AC motors, and
high current/low voltage is harder to work with (and thus less reliable)
than higher voltage/lower current.

I want
to go totally electric (no gas)

Then run your generator when you need the power, and use the batteries for
the small stuff.

A reasonable battery bank can run your lights, refrigerator, and through an
inverter you can run small appliances (such as a blender or short use of the
microwave), TV, stereo, computers, etc.

When looking for 24 volt equipment, take a look at commercial and "mega
yacht" sources. Lights shouldn't be a problem, but you may find that
electronics are scarce and very expensive. Since your battery bank is most
likely made up of a number of batteries in series, you could tap off a 12
volt line and have both a 12 volt and 24 volt system. Use the 24 volts for
the higher wattage stuff, such as the inverter, windlass and lights. Use
the 12 volts for the electronics, such as depth finders, VHF, etc.

Run the stove, water heater, and air conditioning off the generator.

Rod McInnis

"Rod McInnis" wrote in message
...

"Larry W4CSC" wrote in message
...


I've never figured out why boats in cold climates waste all this
energy going out the exhaust. It's SO easy to make a cast iron heat
exchanger in a dry stack, right next to...or even right IN the
exhaust
manifold that will just roast your ears with free heat.

the old Volkswagon Beetles used a heat exchanger off the exhaust
manifolds
to heat the car! It was actually pretty nice on cold mornings, as the
heater worked almost instantly after starting the car.

Are you insane? Suffering from Amnesia? We had one of those Beetles in
Minnesota from 1973 until 1985. My wife used to wonder why the other
people in the grocery store weren't wearing snowmobile suits. We
learned to drive one handed so we could scrape the inside of the
windshield with the other. Do you realize how long it takes to heat a
piece of cast iron and the sheet metal floorpan duct when it starts out
at zero, and the heat is coming from 750cc of motor (there were two, so
each only got half the exhaust)

Sheeesh.

del cecchi

"del cecchi" wrote in message
...

"Rod McInnis" wrote in message
...

"Larry W4CSC" wrote in message
...


I've never figured out why boats in cold climates waste all this
energy going out the exhaust. It's SO easy to make a cast iron heat
exchanger in a dry stack, right next to...or even right IN the
exhaust
manifold that will just roast your ears with free heat.

the old Volkswagon Beetles used a heat exchanger off the exhaust
manifolds
to heat the car! It was actually pretty nice on cold mornings, as the
heater worked almost instantly after starting the car.

Are you insane? Suffering from Amnesia? We had one of those Beetles in
Minnesota from 1973 until 1985. My wife used to wonder why the other
people in the grocery store weren't wearing snowmobile suits. We
learned to drive one handed so we could scrape the inside of the
windshield with the other. Do you realize how long it takes to heat a
piece of cast iron and the sheet metal floorpan duct when it starts out
at zero, and the heat is coming from 750cc of motor (there were two, so
each only got half the exhaust)

Sheeesh.

del cecchi


Can you say - southwind heater?
Who needs a passenger seat anyway?

Ahh - blessed warmth!

Mark Browne

"misia" wrote in message
ail.from.there...


I hear you. I absolutely agree on everything you said. The battery bank
would be
15kWh capable AGM (for 100%50% discharge).

So, that would be like 10 of the 8D size batteries?

I hope this is a big boat you are putting these on. That is a lot of space,
not to mention the ~1500 pounds.

Rod McInnis

On Mon, 12 Jan 2004 16:28:35 -0800, "Rod McInnis"
wrote:


"Larry W4CSC" wrote in message
...


I've never figured out why boats in cold climates waste all this
energy going out the exhaust. It's SO easy to make a cast iron heat
exchanger in a dry stack, right next to...or even right IN the exhaust
manifold that will just roast your ears with free heat.

the old Volkswagon Beetles used a heat exchanger off the exhaust manifolds
to heat the car! It was actually pretty nice on cold mornings, as the
heater worked almost instantly after starting the car.

Yes, and it heated near instantly as you started the cold engine.
Didn't take long to heat the heat exchanger directly in the flames!

My VW 411 station wagon with the Porche 914 pancake engine in it did
it even better.....It had a gasoline furnace you could turn on BEFORE
starting the car by turning on a timer on the dash that limited how
long it would run without starting the car. It was like heating with
a jet engine....and sounded like one!


We retrieve some of it with the hot water heater hooked to the water
jacket. Too bad so much heat is simply wasted.


There is a lot of free heat to be had from the engine. The only drawback is
that the engine has to be running! Not what you want when you are swinging
on the hook!

Agreed, but I suppose it would depend on how cold your feet are...(c;

For those times, perhaps what is needed is a black plastic water
heater you could haul up the mainmast to heat some medium for the
night. There's more to solar energy than battery chargers that are 2%
efficient. I know someone who has homemade panels hanging from the
sunny side window sills to the ground below. When the sun shines on
them, it superheats the air on the front of the panel. This air rises
and enters the room through the window sill opening. The hot air
rising sucks house air from the bottom side of the sill into the heat
exchanger to replace that already heated.

When he first built them, he made one for every window. His living
room has 3 that sun hits. Fed up with sweating at 90F, he reinvented
thermostatic dampers to control how MUCH of the hot air was allowed
into the house. At first it was like a furnace out of control! A
boat model could simply be a vertical panel hung over the hatch with a
simple 12V muffin fan to force the air up into the panel which can't
be self-flushing like his home system is. With all the boat stink
problems everyone has, maybe a solar panel could have an opening
outside, heat the air then let the fan suck it into the boat to
displace stinky, wet air out through another hatch.....the leaky one
into the cockpit on a sailboat. Wouldn't hot fresh air be nice all
day in winter?

Del, did anyone ever inspect the dampers to see if they were opening?
The air cooling coming out of my 1KW Honda EU1000i genset, a tiny
engine, more than adequately heats my Air Force stepvan at 30F in 30
minutes. A couple of loops of copper tubing heat exchange more from
the exhaust before it goes outside through the deck.



On Mon, 12 Jan 2004 22:04:10 -0600, "del cecchi"
wrote:


"Rod McInnis" wrote in message
...

"Larry W4CSC" wrote in message
...


I've never figured out why boats in cold climates waste all this
energy going out the exhaust. It's SO easy to make a cast iron heat
exchanger in a dry stack, right next to...or even right IN the
exhaust
manifold that will just roast your ears with free heat.

the old Volkswagon Beetles used a heat exchanger off the exhaust
manifolds
to heat the car! It was actually pretty nice on cold mornings, as the
heater worked almost instantly after starting the car.

Are you insane? Suffering from Amnesia? We had one of those Beetles in
Minnesota from 1973 until 1985. My wife used to wonder why the other
people in the grocery store weren't wearing snowmobile suits. We
learned to drive one handed so we could scrape the inside of the
windshield with the other. Do you realize how long it takes to heat a
piece of cast iron and the sheet metal floorpan duct when it starts out
at zero, and the heat is coming from 750cc of motor (there were two, so
each only got half the exhaust)

Sheeesh.

del cecchi

"Larry W4CSC" wrote in message
...
efficient. I know someone who has homemade panels hanging from the
sunny side window sills to the ground below. When the sun shines on
them, it superheats the air on the front of the panel. This air rises
and enters the room through the window sill opening. The hot air
rising sucks house air from the bottom side of the sill into the heat
exchanger to replace that already heated.

Before they went to flush toilets, the campground we used in Maine as a kid
had 'solar holers' and solar showers. The solar holers were "restroom"
outhouses - like a multiple stall restroom but no water - with south facing
black-inside/clear-top vertical risers with the intake at the bottom and the
exhaust well above the roof of the outhouse, which pulled fresh air through
the outhouses and out the top. No stinky outhouse. Likewise, the hot water
in the showers was a solar black-pipe covering on the bath house roof,
faciing south. Summer in Maine has a *lot* of sunshine hours, so they never
ran out of hot water unless it was raining...

Marvelous thing, the sun....

L8R

Skip

--
"And then again, when you sit at the helm of your little ship on a clear
night, and gaze at the countless stars overhead, and realize that you are
quite alone on a great, wide sea, it is apt to occur to you that in the
general scheme of things you are merely an insignificant speck on the
surface of the ocean; and are not nearly so important or as self-sufficient
as you thought you were. Which is an exceedingly wholesome thought, and one
that may effect a permanent change in your deportment that will be greatly
appreciated by your friends."- James S. Pitkin