alternative power sources
HI Dennis,
Of course you are right and I did throw in ohms law without thinking about
the math but knowing that 24 volts would use half the current drain and
smaller wiring, my apologies to everyone for that. My main purpose was
power conservation and reducing weight that would reduce fuel burn and
generally create a greener boat.
As for 120/240 volts AC being lethal! It should be no more lethal on a boat
than it is in the home if it is correctly wired and protected and that
should include using it for an anchor windlass, bow thrusters and davits.
Shore power, generators and invertors supply it for use onboard and it is
used on larger vessels to the same degree you would use it at home. The
lethal aspect has probably been passed down from having 120 volts on small
wet sailing boats.
Cheers,
Graham
Captain Graham Pfister
President & Principle Designer
TrawlerCat Marine Designs
Message: 15
Date: Tue, 17 Nov 2009 17:04:24 -0600
From: "Dennis Raedeke" dennis@wildmountain.com
To: "Power Catamaran List" power-catamaran@lists.samurai.com
Subject: Re: [PCW] alternative power sources
Message-ID: B12C9B76E13F488FBC0A78080A3438A6@dennisr
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=original
Graham,
There is no power conservation using 24v compared to 12v. P=I X E If E= 12
and I= 10 P=120 If E=24 and I= 5 P=120. As you can see the power is the
same and the energy to produce it would be the same. The advantage of using
24v is that as you can see the current is 1/2/ as you say the wire size is
reduced and you will have less heat for the same amount of power in
alternators and motors. When you use 24v as the primary voltage you will
need to also have a 12v battery for the items that are not available in 24v.
Fortunately there is an equalizer sold the will draw 12 equally from the 2
batteries that make up the 24v.
The suggestion of using the lethal voltage of 120vac or 240vac for the items
you suggest is not to my likening.
120/240 on boats can be more dangerous, since you are in an environment with
moisture, which can provide a path to ground IF you are plugged in to shore
power. Under generator or inverter it is less of a problem since they are
floating grounds. Also an isolation transformer provides some of the same
security, but make no mistake, if you can provide a better path to ground than
the wire on a polarized system hooked to shore power, it will use you.
----- Original Message -----
From: Grahammailto:graham@trawlercatmarine.com
To:
power-catamaran@lists.samurai.commailto:power-catamaran@lists.samurai.com
Sent: Wednesday, November 18, 2009 2:00 PM
Subject: [PCW] alternative power sources
HI Dennis,
Of course you are right and I did throw in ohms law without thinking about
the math but knowing that 24 volts would use half the current drain and
smaller wiring, my apologies to everyone for that. My main purpose was
power conservation and reducing weight that would reduce fuel burn and
generally create a greener boat.
As for 120/240 volts AC being lethal! It should be no more lethal on a
boat
than it is in the home if it is correctly wired and protected and that
should include using it for an anchor windlass, bow thrusters and davits.
Shore power, generators and invertors supply it for use onboard and it is
used on larger vessels to the same degree you would use it at home. The
lethal aspect has probably been passed down from having 120 volts on small
wet sailing boats.
Cheers,
Graham
Captain Graham Pfister
President & Principle Designer
TrawlerCat Marine Designs
Message: 15
Date: Tue, 17 Nov 2009 17:04:24 -0600
From: "Dennis Raedeke"
<dennis@wildmountain.commailto:dennis@wildmountain.com>
To: "Power Catamaran List"
<power-catamaran@lists.samurai.commailto:power-catamaran@lists.samurai.com>
Subject: Re: [PCW] alternative power sources
Message-ID:
<B12C9B76E13F488FBC0A78080A3438A6@dennisr<mailto:B12C9B76E13F488FBC0A78080A34
38A6@dennisr>>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=original
Graham,
There is no power conservation using 24v compared to 12v. P=I X E If E= 12
and I= 10 P=120 If E=24 and I= 5 P=120. As you can see the power is the
same and the energy to produce it would be the same. The advantage of using
24v is that as you can see the current is 1/2/ as you say the wire size is
reduced and you will have less heat for the same amount of power in
alternators and motors. When you use 24v as the primary voltage you will
need to also have a 12v battery for the items that are not available in
24v.
Fortunately there is an equalizer sold the will draw 12 equally from the 2
batteries that make up the 24v.
The suggestion of using the lethal voltage of 120vac or 240vac for the
items
you suggest is not to my likening.
Power-Catamaran Mailing List
----- Original Message -----
From: "Pat Reischmann" preischmann@msn.com
120/240 on boats can be more dangerous, since you are in an environment
with
moisture, which can provide a path to ground IF you are plugged in to
shore
power. Under generator or inverter it is less of a problem since they are
floating grounds. Also an isolation transformer provides some of the same
security, but make no mistake, if you can provide a better path to ground
than
the wire on a polarized system hooked to shore power, it will use you.
REPLY
Possibly true on older poorly wired boats. Power demand levels on boats 65
feet and over pretty much requires the use of 120v or 230v AC
Modern leakage current detectors have pretty well eliminated the horror
stories of yesteryear.
Arild
True they do, and most of the time they are running on generators, and all of
them have isolation transformers. This however is not true for the other 90%
of the pleasure boat industry, and I include boats being built currently. 90%
of manufacturers production or custom do not install isolation transformers,
and many do not adhere to ABYC when it comes to GFI protection etc. Today
there is no watch dog or building standard required in this country to build
boats, unless they are for commercial use. Yes things are better because of
ABYC , ISO, NMMA, and others, but the quality of connections, wire, and
electrical engineering are still left up to the conscience and pocket book of
the builder and his commitment to quality control.
----- Original Message -----
From: 2elnav@netbistro.commailto:2elnav@netbistro.com
To: Power Catamaran Listmailto:power-catamaran@lists.samurai.com
Sent: Wednesday, November 18, 2009 2:40 PM
Subject: [PCW] AC power versus DC
----- Original Message -----
From: "Pat Reischmann" <preischmann@msn.commailto:preischmann@msn.com>
120/240 on boats can be more dangerous, since you are in an environment
with
moisture, which can provide a path to ground IF you are plugged in to
shore
power. Under generator or inverter it is less of a problem since they are
floating grounds. Also an isolation transformer provides some of the same
security, but make no mistake, if you can provide a better path to ground
than
the wire on a polarized system hooked to shore power, it will use you.
REPLY
Possibly true on older poorly wired boats. Power demand levels on boats 65
feet and over pretty much requires the use of 120v or 230v AC
Modern leakage current detectors have pretty well eliminated the horror
stories of yesteryear.
Arild
Power-Catamaran Mailing List
On Wed, 2009-11-18 at 15:00 -0500, Pat Reischmann wrote:
many do not adhere to ABYC when it comes to GFI protection etc. Today
there is no watch dog or building standard required in this country to build
boats, unless they are for commercial use.
REPLY
No law says you have to only do the minimum. Several countries have more
extensive and detailed standards. Sometimes serves as good example of
new innovations. If as you say there are no real requirements to do
anything, it also means a designer is free to experiment with better
techniques.
Toroidal isolation transformers weigh less than traditional iron cored
transformers of same kilowatt capacity. We can build a better, lighter
weight electrical system. how about taking 500 pounds out of a typical
system for a 50 foot boat. We can even build a system having less wire
and complexcity than the traditional approach without going to a
computerized digital control system like NMEA 2000 or ePlex.
Sorry, when you say "We" are you a boat builder? I am all for innovation but
"Designer experiments" can cost a lot of money in this business, and making
money is important as is building good boats, otherwise it's a hobby. When I
speak on these subjects it's about doing it in this country.
----- Original Message -----
From: Arild Jensenmailto:2elnav@netbistro.com
To: Power Catamaran Listmailto:power-catamaran@lists.samurai.com
Sent: Wednesday, November 18, 2009 3:28 PM
Subject: Re: [PCW] AC power versus DC
On Wed, 2009-11-18 at 15:00 -0500, Pat Reischmann wrote:
many do not adhere to ABYC when it comes to GFI protection etc. Today
there is no watch dog or building standard required in this country to
build
boats, unless they are for commercial use.
REPLY
No law says you have to only do the minimum. Several countries have more
extensive and detailed standards. Sometimes serves as good example of
new innovations. If as you say there are no real requirements to do
anything, it also means a designer is free to experiment with better
techniques.
Toroidal isolation transformers weigh less than traditional iron cored
transformers of same kilowatt capacity. We can build a better, lighter
weight electrical system. how about taking 500 pounds out of a typical
system for a 50 foot boat. We can even build a system having less wire
and complexcity than the traditional approach without going to a
computerized digital control system like NMEA 2000 or ePlex.
Power-Catamaran Mailing List