24 VDC appliances?
 

"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

24 VDC appliances?
 

"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

24 VDC appliances?
 

"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

24 VDC appliances?
 

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

24 VDC appliances?
 

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

24 VDC appliances?
 

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

24 VDC appliances?
 

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

24 VDC appliances?
 

"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

24 VDC appliances?
 

"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

24 VDC appliances?
 

"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

24 VDC appliances?
 

"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

24 VDC appliances?
 

"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

24 VDC appliances?
 

"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

24 VDC appliances?
 

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?

24 VDC appliances?
 

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?

24 VDC appliances?
 

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

24 VDC appliances?
 

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

24 VDC appliances?
 

"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

24 VDC appliances?
 

"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

24 VDC appliances?
 

(Larry W4CSC) wrote
My shop heater in winter is a 1KW Honda EU1000i power plant. I welded a
pipe nipple on the little exhaust port . . .

Hmm. The manual that came with my EU1000i went to great lengths in
several languages to *don't do that*! I suppose if the length was
short, not too restrictive, not near flammable materials, it could
work.

Its quiet enclosure . . . hidden away behind the cabinets.

Hmm, The EU1000i wasn't designed to operate in an enclosure, might be
hard on the plastic parts. Although big ventilation grates might make
such an installation viable.

Of course, restricting the exhaust with a long length of tubing and
letting the generator recycle a good dose of it's own (hot) cooling
air would just make it work harder and produce *more* heat g.

24 VDC appliances?
 

(Larry W4CSC) wrote
My shop heater in winter is a 1KW Honda EU1000i power plant. I welded a
pipe nipple on the little exhaust port . . .

Hmm. The manual that came with my EU1000i went to great lengths in
several languages to *don't do that*! I suppose if the length was
short, not too restrictive, not near flammable materials, it could
work.

Its quiet enclosure . . . hidden away behind the cabinets.

Hmm, The EU1000i wasn't designed to operate in an enclosure, might be
hard on the plastic parts. Although big ventilation grates might make
such an installation viable.

Of course, restricting the exhaust with a long length of tubing and
letting the generator recycle a good dose of it's own (hot) cooling
air would just make it work harder and produce *more* heat g.

24 VDC appliances?
 

The warning in the manual is for the carbon monoxide and to keep you
from suing them if you do what they tell you not to......

The enclosure has a big outlet where the heat comes out the end of the
genset and two intakes, one in the bottom and one near the bottom on
the end with the outlets. The plastic doesn't even get as warm as it
would sitting in the sun being eaten alive by the UV rays from the
sunshine. It runs 8 hours a day on the road all summer in a modified
tool box bolted to the back door it just fits in. It's cooler in the
cabinet than in the sun because of the volume of air the blower in it
creates....

Operating in the van, in winter, the only end that gets warm is where
the hot air comes out of it to heat my truck. I'd guess doing this
recovers near 95% of the energy of the consumed fuel.

Too bad boats don't use Deutz air-cooled diesels. You could dump the
heat overboard in the summer around the dry stack and divert it into
the cabin in winter to recover the waste heat with a
thermostatically-controlled shutter to regulate its cabin temperature
through a muffler to block the noise. I had Deutz V-16 engines
driving 200KW gensets in Iran and they were fantastic engines, even
running where the OAT was over 100F all day long! One injector
clogged in 2 years and that was our fault some idiot put the filter in
wrong. Change the oil every 150 hours and she'd just run and run
24/7/365



On 13 Jan 2004 21:51:56 -0800, (Mark) wrote:

(Larry W4CSC) wrote
My shop heater in winter is a 1KW Honda EU1000i power plant. I welded a
pipe nipple on the little exhaust port . . .

Hmm. The manual that came with my EU1000i went to great lengths in
several languages to *don't do that*! I suppose if the length was
short, not too restrictive, not near flammable materials, it could
work.

Its quiet enclosure . . . hidden away behind the cabinets.

Hmm, The EU1000i wasn't designed to operate in an enclosure, might be
hard on the plastic parts. Although big ventilation grates might make
such an installation viable.

Of course, restricting the exhaust with a long length of tubing and
letting the generator recycle a good dose of it's own (hot) cooling
air would just make it work harder and produce *more* heat g.

24 VDC appliances?
 

The warning in the manual is for the carbon monoxide and to keep you
from suing them if you do what they tell you not to......

The enclosure has a big outlet where the heat comes out the end of the
genset and two intakes, one in the bottom and one near the bottom on
the end with the outlets. The plastic doesn't even get as warm as it
would sitting in the sun being eaten alive by the UV rays from the
sunshine. It runs 8 hours a day on the road all summer in a modified
tool box bolted to the back door it just fits in. It's cooler in the
cabinet than in the sun because of the volume of air the blower in it
creates....

Operating in the van, in winter, the only end that gets warm is where
the hot air comes out of it to heat my truck. I'd guess doing this
recovers near 95% of the energy of the consumed fuel.

Too bad boats don't use Deutz air-cooled diesels. You could dump the
heat overboard in the summer around the dry stack and divert it into
the cabin in winter to recover the waste heat with a
thermostatically-controlled shutter to regulate its cabin temperature
through a muffler to block the noise. I had Deutz V-16 engines
driving 200KW gensets in Iran and they were fantastic engines, even
running where the OAT was over 100F all day long! One injector
clogged in 2 years and that was our fault some idiot put the filter in
wrong. Change the oil every 150 hours and she'd just run and run
24/7/365



On 13 Jan 2004 21:51:56 -0800, (Mark) wrote:

(Larry W4CSC) wrote
My shop heater in winter is a 1KW Honda EU1000i power plant. I welded a
pipe nipple on the little exhaust port . . .

Hmm. The manual that came with my EU1000i went to great lengths in
several languages to *don't do that*! I suppose if the length was
short, not too restrictive, not near flammable materials, it could
work.

Its quiet enclosure . . . hidden away behind the cabinets.

Hmm, The EU1000i wasn't designed to operate in an enclosure, might be
hard on the plastic parts. Although big ventilation grates might make
such an installation viable.

Of course, restricting the exhaust with a long length of tubing and
letting the generator recycle a good dose of it's own (hot) cooling
air would just make it work harder and produce *more* heat g.

24 VDC appliances?
 

"Larry W4CSC" wrote in message
...


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.

What you would need is thermal mass. The key word here is "mass". It will
take a lot of it, if you intend to pull heat out of it all night long. And
it will be heavy. How much weight would you feel comfortable hauling up the
mast?


I know someone who has homemade panels hanging from the
sunny side window sills to the ground below.

This works great IF you have a sunny exposure BELOW the area where you use
or store the energy. I have known people who live on a steep hill with a
southern exposure (northern hemisphere, which means that the slope gets a
lot of sun). It is somewhat common to construct a solar heater out of black
ABS pipe that runs down the hill a ways. Heating swimming pools is common,
but I know one person who had copper pipes embedded in the concrete slab of
his home and ciculated the warm water to heat the slab.

The key is that warm air/water will rise, so if the source of heat is lower
you can create a natural flow of water. If the source of heat is above,
then you will need to pump the water, and you may end up using more energy
pumping than you would have heating.

Rod

24 VDC appliances?
 

"Larry W4CSC" wrote in message
...


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.

What you would need is thermal mass. The key word here is "mass". It will
take a lot of it, if you intend to pull heat out of it all night long. And
it will be heavy. How much weight would you feel comfortable hauling up the
mast?


I know someone who has homemade panels hanging from the
sunny side window sills to the ground below.

This works great IF you have a sunny exposure BELOW the area where you use
or store the energy. I have known people who live on a steep hill with a
southern exposure (northern hemisphere, which means that the slope gets a
lot of sun). It is somewhat common to construct a solar heater out of black
ABS pipe that runs down the hill a ways. Heating swimming pools is common,
but I know one person who had copper pipes embedded in the concrete slab of
his home and ciculated the warm water to heat the slab.

The key is that warm air/water will rise, so if the source of heat is lower
you can create a natural flow of water. If the source of heat is above,
then you will need to pump the water, and you may end up using more energy
pumping than you would have heating.

Rod

24 VDC appliances?
 

Fatal Error.
The heating element is resistive. 120V 2KW element is approx 7 ohms. Reduce
voltage to 24 v and current draw drops to 3.5 amps. Power is not a constant.
"Larry W4CSC" wrote in message
...
Wouldn't actually make much of a difference. If the 2KW water heater
were running on 12V, it would draw 167A. On 24V it would still draw
83.3A, draining the batteries in a matter of minutes, not hours......

Then, comes the problem of battery real estate. in the same space it
takes to put 500 amp-hours of 12V batteries, you get 250 amp-hours of
24V batteries.....the same exact kilowatt-hour rating. If you
parallel two 130AH 12V deep cycles, you get 260AH at 12V. If you
series them, you get 130AH at 24V......the same exact power output in
KwH. You can use smaller wire, though....(c;

Running large electrical loads of batteries is a pipe dream on these
boats at any voltage. There just isn't room for a proper battery
bank, like you'd need. A 350AH large golf cart battery, which is only
6 volts, is only 2.1Kwh but at a very low rate like 20A, not 200A. We
run 4 of these monsters in 2 banks in series-parallel to get 12V at
700AH in Lionheart's engine room. You can't use all 700AH because
that would really shorten their life, so you only discharge them about
400-500AH before charging, and that's stretching it. Then, it's so
hard to get that last 15% to full charge, there's no point running the
charging engine for hours more so you lose 15% more capacity charging
them only up to 85% of full specific gravity. This battery bank of 4
is about 4' x 20" x 24" tall and 400 pounds of ballast. In
comparison, each CELL of 126 cells in a WW2 submarine is about 7' high
by 4' by 3' and puts out 2V at 6,250AH to drive the sub 48 hours at
only 2 knots on TWO 126 cell banks...one forward, one aft. WW2 subs
carried nearly 1000 TONS of batteries to accomplish this level of
power. No wonder they sank a perfectly good boat!

With an 80A alternator running flat out, you can recharge Lionhearts
400AH "standard discharge" in about 5.5 hours. Charging too fast, and
this is almost too fast, makes charging more dangerous (heat) and
boils off the electrolyte (hydrogen). With a tapering charge, it
takes longer...6-7 hours. At 80A, the fanbelt better be TIGHT!
Charging monster battery banks is another problem altogether.....

Nothing is funnier than a boater with a new 4KW inverter carrying his
electric heater down the dock with a big smile on his face.......

The real answer is a super quiet insulated diesel genset with a small
starting battery and a hundred gallons of #2 fuel oil.....an immense
pool of liquid power...(c; The Navy prefers nuclear power but the
refueling is messy.



On Sat, 10 Jan 2004 22:20:53 GMT, misia
wrote:

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 want
to go totally electric (no gas)

Regards Mi

24 VDC appliances?
 

Fatal Error.
The heating element is resistive. 120V 2KW element is approx 7 ohms. Reduce
voltage to 24 v and current draw drops to 3.5 amps. Power is not a constant.
"Larry W4CSC" wrote in message
...
Wouldn't actually make much of a difference. If the 2KW water heater
were running on 12V, it would draw 167A. On 24V it would still draw
83.3A, draining the batteries in a matter of minutes, not hours......

Then, comes the problem of battery real estate. in the same space it
takes to put 500 amp-hours of 12V batteries, you get 250 amp-hours of
24V batteries.....the same exact kilowatt-hour rating. If you
parallel two 130AH 12V deep cycles, you get 260AH at 12V. If you
series them, you get 130AH at 24V......the same exact power output in
KwH. You can use smaller wire, though....(c;

Running large electrical loads of batteries is a pipe dream on these
boats at any voltage. There just isn't room for a proper battery
bank, like you'd need. A 350AH large golf cart battery, which is only
6 volts, is only 2.1Kwh but at a very low rate like 20A, not 200A. We
run 4 of these monsters in 2 banks in series-parallel to get 12V at
700AH in Lionheart's engine room. You can't use all 700AH because
that would really shorten their life, so you only discharge them about
400-500AH before charging, and that's stretching it. Then, it's so
hard to get that last 15% to full charge, there's no point running the
charging engine for hours more so you lose 15% more capacity charging
them only up to 85% of full specific gravity. This battery bank of 4
is about 4' x 20" x 24" tall and 400 pounds of ballast. In
comparison, each CELL of 126 cells in a WW2 submarine is about 7' high
by 4' by 3' and puts out 2V at 6,250AH to drive the sub 48 hours at
only 2 knots on TWO 126 cell banks...one forward, one aft. WW2 subs
carried nearly 1000 TONS of batteries to accomplish this level of
power. No wonder they sank a perfectly good boat!

With an 80A alternator running flat out, you can recharge Lionhearts
400AH "standard discharge" in about 5.5 hours. Charging too fast, and
this is almost too fast, makes charging more dangerous (heat) and
boils off the electrolyte (hydrogen). With a tapering charge, it
takes longer...6-7 hours. At 80A, the fanbelt better be TIGHT!
Charging monster battery banks is another problem altogether.....

Nothing is funnier than a boater with a new 4KW inverter carrying his
electric heater down the dock with a big smile on his face.......

The real answer is a super quiet insulated diesel genset with a small
starting battery and a hundred gallons of #2 fuel oil.....an immense
pool of liquid power...(c; The Navy prefers nuclear power but the
refueling is messy.



On Sat, 10 Jan 2004 22:20:53 GMT, misia
wrote:

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 want
to go totally electric (no gas)

Regards Mi

24 VDC appliances?
 

We use both 12 and 24 systems. They higher the required amperage the better
it is to use a higher voltage. We run winches, fridge, and autopilot hyd
motor with 24 volt. All else is 12v.
We use two 12 volt banks and one very large 24 volt bank. Charging is from
both 12 and 24v HO alternators but are getting ready to add additional
charging systems.

Gas for cooking, diesel for heating. Hate to run a $20k motor to heat the
cabin.

Good luck,

B
"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 want
to go totally electric (no gas)

Regards Mi

24 VDC appliances?
 

We use both 12 and 24 systems. They higher the required amperage the better
it is to use a higher voltage. We run winches, fridge, and autopilot hyd
motor with 24 volt. All else is 12v.
We use two 12 volt banks and one very large 24 volt bank. Charging is from
both 12 and 24v HO alternators but are getting ready to add additional
charging systems.

Gas for cooking, diesel for heating. Hate to run a $20k motor to heat the
cabin.

Good luck,

B
"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 want
to go totally electric (no gas)

Regards Mi

24 VDC appliances?
 

On Wed, 14 Jan 2004 12:36:42 -0800, "Rod McInnis"
wrote:


"Larry W4CSC" wrote in message
...


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.

What you would need is thermal mass. The key word here is "mass". It will
take a lot of it, if you intend to pull heat out of it all night long. And
it will be heavy. How much weight would you feel comfortable hauling up the
mast?

How about we transfer the heat into the thousands of pounds of lead in
the KEEL? Is that mass enough??...(c;

I was referring to a way we could heat the cabin in the DAYTIME, to
reduce the cost of load of heating it, not eliminate it. If you
pumped air from the cabin up into a black plastic bag, of sorts,
exposed to the sun, the air coming back out into the cabin would be
more than enough to heat the boat in the daytime....for free.

I know someone who has homemade panels hanging from the
sunny side window sills to the ground below.

This works great IF you have a sunny exposure BELOW the area where you use
or store the energy. I have known people who live on a steep hill with a
southern exposure (northern hemisphere, which means that the slope gets a
lot of sun). It is somewhat common to construct a solar heater out of black
ABS pipe that runs down the hill a ways. Heating swimming pools is common,
but I know one person who had copper pipes embedded in the concrete slab of
his home and ciculated the warm water to heat the slab.

Agreed, hence the FAN to overcome the problem, forcing air to
circulate against its will into and out of the bag.

The key is that warm air/water will rise, so if the source of heat is lower
you can create a natural flow of water. If the source of heat is above,
then you will need to pump the water, and you may end up using more energy
pumping than you would have heating.

Rod

Pumping air into the thing is easy. 12V muffin fans draw almost no
power and move a LOT of air.

24 VDC appliances?
 

On Wed, 14 Jan 2004 12:36:42 -0800, "Rod McInnis"
wrote:


"Larry W4CSC" wrote in message
...


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.

What you would need is thermal mass. The key word here is "mass". It will
take a lot of it, if you intend to pull heat out of it all night long. And
it will be heavy. How much weight would you feel comfortable hauling up the
mast?

How about we transfer the heat into the thousands of pounds of lead in
the KEEL? Is that mass enough??...(c;

I was referring to a way we could heat the cabin in the DAYTIME, to
reduce the cost of load of heating it, not eliminate it. If you
pumped air from the cabin up into a black plastic bag, of sorts,
exposed to the sun, the air coming back out into the cabin would be
more than enough to heat the boat in the daytime....for free.

I know someone who has homemade panels hanging from the
sunny side window sills to the ground below.

This works great IF you have a sunny exposure BELOW the area where you use
or store the energy. I have known people who live on a steep hill with a
southern exposure (northern hemisphere, which means that the slope gets a
lot of sun). It is somewhat common to construct a solar heater out of black
ABS pipe that runs down the hill a ways. Heating swimming pools is common,
but I know one person who had copper pipes embedded in the concrete slab of
his home and ciculated the warm water to heat the slab.

Agreed, hence the FAN to overcome the problem, forcing air to
circulate against its will into and out of the bag.

The key is that warm air/water will rise, so if the source of heat is lower
you can create a natural flow of water. If the source of heat is above,
then you will need to pump the water, and you may end up using more energy
pumping than you would have heating.

Rod

Pumping air into the thing is easy. 12V muffin fans draw almost no
power and move a LOT of air.

24 VDC appliances?
 

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
Keep the world clean - no HTML in news or mail !

24 VDC appliances?
 

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
Keep the world clean - no HTML in news or mail !

24 VDC appliances?
 

I knew what Larry intended: why didn't you?

Brian W

On Wed, 14 Jan 2004 20:59:50 GMT, "Morex Support"
wrote:

Fatal Error.
The heating element is resistive. 120V 2KW element is approx 7 ohms. Reduce
voltage to 24 v and current draw drops to 3.5 amps. Power is not a constant.
"Larry W4CSC" wrote in message
...
Wouldn't actually make much of a difference. If the 2KW water heater
were running on 12V, it would draw 167A. On 24V it would still draw
83.3A, draining the batteries in a matter of minutes, not hours......

24 VDC appliances?
 

I knew what Larry intended: why didn't you?

Brian W

On Wed, 14 Jan 2004 20:59:50 GMT, "Morex Support"
wrote:

Fatal Error.
The heating element is resistive. 120V 2KW element is approx 7 ohms. Reduce
voltage to 24 v and current draw drops to 3.5 amps. Power is not a constant.
"Larry W4CSC" wrote in message
...
Wouldn't actually make much of a difference. If the 2KW water heater
were running on 12V, it would draw 167A. On 24V it would still draw
83.3A, draining the batteries in a matter of minutes, not hours......

24 VDC appliances?
 

If y'all would just hang on for the next design generation of auto
electronics, you might could use the 42 volt electrics.....

Brian Whatcott Altus OK

On Wed, 14 Jan 2004 17:12:08 -0500, "Bryan B"
wrote:

We use both 12 and 24 systems. They higher the required amperage the better
it is to use a higher voltage. We run winches, fridge, and autopilot hyd
motor with 24 volt. All else is 12v.
We use two 12 volt banks and one very large 24 volt bank. Charging is from
both 12 and 24v HO alternators but are getting ready to add additional
charging systems.

Gas for cooking, diesel for heating. Hate to run a $20k motor to heat the
cabin.

Good luck,

B
"misia" wrote in message
mail.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 want
to go totally electric (no gas)

Regards Mi

24 VDC appliances?
 

If y'all would just hang on for the next design generation of auto
electronics, you might could use the 42 volt electrics.....

Brian Whatcott Altus OK

On Wed, 14 Jan 2004 17:12:08 -0500, "Bryan B"
wrote:

We use both 12 and 24 systems. They higher the required amperage the better
it is to use a higher voltage. We run winches, fridge, and autopilot hyd
motor with 24 volt. All else is 12v.
We use two 12 volt banks and one very large 24 volt bank. Charging is from
both 12 and 24v HO alternators but are getting ready to add additional
charging systems.

Gas for cooking, diesel for heating. Hate to run a $20k motor to heat the
cabin.

Good luck,

B
"misia" wrote in message
mail.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 want
to go totally electric (no gas)

Regards Mi

24 VDC appliances?
 

"Morex Support" wrote in message
able.rogers.com...
Fatal Error.
The heating element is resistive. 120V 2KW element is approx 7 ohms.
Reduce
voltage to 24 v and current draw drops to 3.5 amps. Power is not a
constant.


I am sure that Larry wasn't suggesting that a 120 volt heating element be
used at 12 volts. What he was suggesting is that IF a 24 volt equivalent
device could be found, then it would draw 83 amps.

Oh, and by the way, your example is way off also. In most cases, heating
elements have a dramatic increase in resistance as they heat up. The element
in question may have a resistance of 7 ohms when it is dissipating 2KW, but
if you drop the voltage the resistance will drop also.

This resistance change is even more dramatic on a light bulb. Take a low
wattage light bulb and measure the resistance when it is cold and you may be
surprised! This is why cutting the voltage in half to incandescent lights
does NOT cut the current in half!

Rod McInnis

24 VDC appliances?
 

"Morex Support" wrote in message
able.rogers.com...
Fatal Error.
The heating element is resistive. 120V 2KW element is approx 7 ohms.
Reduce
voltage to 24 v and current draw drops to 3.5 amps. Power is not a
constant.


I am sure that Larry wasn't suggesting that a 120 volt heating element be
used at 12 volts. What he was suggesting is that IF a 24 volt equivalent
device could be found, then it would draw 83 amps.

Oh, and by the way, your example is way off also. In most cases, heating
elements have a dramatic increase in resistance as they heat up. The element
in question may have a resistance of 7 ohms when it is dissipating 2KW, but
if you drop the voltage the resistance will drop also.

This resistance change is even more dramatic on a light bulb. Take a low
wattage light bulb and measure the resistance when it is cold and you may be
surprised! This is why cutting the voltage in half to incandescent lights
does NOT cut the current in half!

Rod McInnis

24 VDC appliances?
 

"Bryan B" wrote in message
...
We use both 12 and 24 systems.


Just out of curiosity, who is "we" ?

Rod