I agree. We actually will have the Spectra watermaker and these are extremely
efficient. I owned one for 5 years on a 31ft boat and with 5 people 2 120W solar
batteries are able to maintain it to provide enough water daily.

If we use spectra, the watermaker will consume approx the same amount of kwh as
the fridge.

We will have the generator as well

M

"Wayne.B" wrote:

On Sun, 11 Jan 2004 22:34:28 GMT, misia
wrote:

I agree electric heater might be the most energy hungry element, especially if
the water has to be retained and temperature maintained in the tank for 10
people onboard.

================================================== ====

To cruise with 10 people in the tropics, you're going to need a water
maker and lots of power. You might as well spring for a decent sized
generator with 110/220 volt power and not worry about finding 24 volt
appliances or stove fuel.

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

I agree electric heater might be the most energy hungry element,
especially if
the water has to be retained and temperature maintained in the tank for 10
people onboard.

This is something that I'm considering to built around hybrid solution.

I came accross this Webasto heater:

http://www.navstore.com/pdf/webasto/Webasto%20TSL17.pdf

What do you think?

I did not check your link, but what you might want to ask your engineer for
would be a design for a water-to-water (Glycol based)heat exchanger to keep
your shower water HOT. This could be done with off-the-shelf electric
components if you have the space, and need only be configured to your space
by your architect and engineer. The electric would be your seldom-used
backup, and you could have your choice of 120, 240, or custom voltage
standard mount heating elements (check off-the-grid, solar, and wind power
resources for these items).

Rob
*
*
*

The exchanger you mention is the engine exhaust exchanger or engine cooling
system exchanger? Do you maybe have any links to practical solutions?

I have found 24V water heater heating elements which could be used as auxiliary.

Regards M



I came accross this Webasto heater:

http://www.navstore.com/pdf/webasto/Webasto%20TSL17.pdf

What do you think?

I did not check your link, but what you might want to ask your engineer for
would be a design for a water-to-water (Glycol based)heat exchanger to keep
your shower water HOT. This could be done with off-the-shelf electric
components if you have the space, and need only be configured to your space
by your architect and engineer. The electric would be your seldom-used
backup, and you could have your choice of 120, 240, or custom voltage
standard mount heating elements (check off-the-grid, solar, and wind power
resources for these items).

Rob
*
*
*

Steve Lusardi wrote:

Mi,
I completely agree with you. Electric is the way to go for both safety and
convenience. I would not have gas unless CNG was available everywhere and
there is the rub. It isn't. The gas of popular choice is LPG and that is
heavier than air. CNG is not. So for me, the best of the rest was electric.
The other responders mentioned the impractcality of using 24V for heating
and cooking. They are correct. In order to be all electric, you must use
240V. Even 120V is impractical because of the wire size required. You need a
large generator, in fact you probably need 2. That means a big boat. The
other problem is the noise from a running generator. I have overcome this
problem with a shaft driven 6KW generator that is silent and a 35KW diesel
generator, but then I have the space. Please be careful of capturing heat
from your engine exhaust. Yes, it is possible, but if you take to much heat
out, you will create acidic deposits that will destroy 316. If you use a
fresh water exchanger and your hot water tank is up to temp and you continue
to run the engine, the exchanger overheats. So you need auxillary cooling,
when your heat demand is low. I guess there is no free lunch.
Steve
"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.

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?

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. I wantMi,
to go totally electric (no gas)

Regards Mi


CNG is not heavier than air???


--

A friend is someone who knows you, understands the essential conflicts in your
thinking, in your morals, and in your philosophy, and like you anyway.

On Sun, 11 Jan 2004 18:02:37 -0600, Dazed and Confuzed
wrote:

CNG is not heavier than air???

=============================

No, it is lighter and will not accumulate in low places such as the
bilge. That has always been CNGs big selling point. For boats big
enough to have a generator/inverter/large battery bank, I'm a great
fan of electric stoves. I've owned an all electric boat for 4 years
now, do a lot of cruising "on the hook", and can't imagine ever going
back to a gas stove of any kind.

Wayne.B wrote:

For boats big
enough to have a generator/inverter/large battery bank, I'm a great
fan of electric stoves. I've owned an all electric boat for 4 years
now, do a lot of cruising "on the hook", and can't imagine ever going
back to a gas stove of any kind.

Just preference I guess, I have had my boat for about 7
years now and while it is big enough to have a couple of
gensets, an inverter, and a very large 120V battery bank I
love my propane stove and wouldn't give it up for anything.

Rick

On Mon, 12 Jan 2004 06:42:21 GMT, Rick
wrote:

Just preference I guess, I have had my boat for about 7
years now and while it is big enough to have a couple of
gensets, an inverter, and a very large 120V battery bank I
love my propane stove and wouldn't give it up for anything.

=================================================

You're choice of course, but I'm not wild about having propane on a
boat, and the convenience of not having separate stove fuel to worry
about is kind of nice.

"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:

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

On Tue, 13 Jan 2004 00:58:42 GMT, Rick
wrote:

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.

Many mid-size yachts (45-80 ft ) have dual 12/24 V systems. 12 V for
electronics that are low-power and often don't come in 24V versions,
24V for Bow/sternthrusters, windlasses, electrical winches etc. Mainly
too keep the cables reasonable.


/Marcus

--
Marcus AAkesson
Gothenburg Callsigns: SM6XFN & SB4779
Sweden
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