Re: [PUP] PPM in general - what should it be ?
Hannu
I think you missed the mark on a few points. You made the point of saying:
Builders build what the market wants. The market does not want safe,
reliable, dependable, cheap-to-maintain items. It does not.
WRONG! People, especially the wives, do want "safe reliable and dependable".
Unfortunately their perception of what provides such characteristics may
not be based on thousands of sea miles of their own personal experience.
Instead they rely on marketing hype.
The people who can afford Nordhavns are accustomed to a certain level of
creature comfort ashore and rightfully expect to have the same in a
permanent home afloat. And why shouldn't they?
Something else to remember. The production boat that is launched today,
was designed two or three years ago. Conditions have changed, technology
has also changed and even people's financial circumstances have changed.
It is therefore hard to have even a new boat meet the latest criteria.
Your repeated use of the word "cheap" and derivatives thereof may in fact
convey the wrong impression. All too often we now see "cheap" consumer
goods that lack quality and reflect the consumer concept of disposable
goods. In the marine world the better choice may well be the more
expensive but totally reliable product that lack in glamor and glitz but
never lets you down.
Sometimes the more expensive item gives longer and better service over a
decade; thus providing a lower total service life cost than the cheap
product.
You wrote:
This makes a PPM;
6:1 L/W ratio
Heavy
Standardisation in mechanical engineering.
Steel
Redundancy in mechanical aspects as much as practical
All components are extremely fit for purpose and chosen for long-term
reliability and capacity
REPLY
I think several list members can and might still object to just about
every point you list with perhaps the one about redundancy in mechanical
aspects.
6:1 L/W suggest that only monohulls are acceptable for passagemaking.
Multi hulls have been making trans oceanic voyages for thousands of
years. More recently several motor multi hulls have made trans oceanic
trips in comfort and safety. But they do not fit the 6:1 ratio.
"Heavy" again suggest only over built heavy displacement hulls are good.
Lighter weight hulls have been built and sucessfully sailed around the
world. As an example; glass light bulbs and fishing net floats that have
floated across an ocean in all kinds of weather dispels the argument that
only heavy construction is safe and durable.
"steel" is yet another assumption that can be disproven. It assumes that
only one hull material is suitable. There are other alternatives that can
make for a lighter weight and equally strong hull. Cold molded wood/epoxy,
aluminum, carbon fiber GRP hulls, all have been made and demonstrated
their durability and strength.
"standardization in mechanical engineering" is so vague, it's hard to even
debate. What "standardization"? It also excludes innovation and adoption
of what has not been done before.
Reading between the lines of your post, I suspect that what you really
meant has more to do with elimination of wasteful energy consumption, and
status seeking options that contribute little or nothing to safe
passagemaking. Those things can rightfully be attributed to over zealous
marketing hype.
As for creature comforts, if the crew is not comfortable, or well rested,
there is no point in making the passage in the first place. Thus making
this whole discussion a moot point.
Best regards
Arild
Bill,
We cook with propane, and rarely fire up the electric oven, although
we do microwave a bit.
In warmish weather, our major current drain is refrigeration. In
winter, in the PNW with short days and heating needs, lights and
heating dominate.
House bank is about 1024 amp/hours at 24v (2048 at 12v). More would
be nice... and if I'm hurting for juice (or find I'm on the low side
at bedtime), then I parallel in 4 additional 8D AGM's that are
normally isolated on the bow and stern thrusters. A dozen 8D AGM's
work nicely. Don't need those extra batteries on thrusters at anchor.
My reserve house bank.
From April to November, our regiment is to run Genset for 3 hours in
the morning, overlapping that with clothes washing and watermaking and
turning on two auxiliary chargers to double my charge rate to >200
amps at 24v.
If its a nice evening and we're BBQ'ing (propane) and sitting outside
until bedtime, we don't have to run in evening. But if we're inside
and watching plasma TV (power suck) and using lots of lighting and
other entertainment gizmos, then we'll run for 2 or 3 hours in early
evening (more watermaking). So 3 to 6 hours a day on Genset depending
on weather and what we're doing.
In winter cold temps, given I haven't installed diesel heat yet, we
run the genset a lot for electric heat. Once I get diesel heat
installed, I'd expect winter run time to drop back to the 6 or 7 hours
a day range. Lots of lighting and we're inside burning power a lot
more due to cold and darkness.
Hope this helps... John
On Dec 7, 2008, at 11:55 AM, bill wrote:
John Marshall,
In a recent post to this list you estimated an extra daily hour of
genset run
time due to sub zero appliances. Also a house bank of 8 8D's and a
charge
rate of 220 amps per hour @ 24V.
May I ask what your normal, at anchor charging regimen, is? And
isn't your
batttery bank on the small side for a boat of your displacement and
inherent
hotel needs?
What do you use for cooking?
thanks,
Bill
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John Marshall wrote
We cook with propane, and rarely fire up the electric oven, although
we do microwave a bit.
In warmish weather, our major current drain is refrigeration. In
winter, in the PNW with short days and heating needs, lights and
heating dominate.
REPLY
Once we get past the obvious issues of sea keeping ability, hull strength
and integrity; the biggest ongoing issue facing all cruising boats is how
to manage the available energy resources. This ranges from the most fuel
efficient cruising speed to getting the maximum return on genset run time.
When fuel was cheap and refueling stations plentiful, it was not as much
of an issue. The new reality seems to be, fuel is getting much more
expensive and many of the smaller fuel docks may not continue to stay in
business.
It has for a long time been considered a given that you stop the generator
when the battery is recharged to about 80% of full charge. Once you get
into the later stages of absorbtion and float charge, the genset is no
longer efficient in terms of amp hour output for fuel consumed input.
I do not propose to question thi, but the one thing about this practice
that is a downside is the fact not all of the lead sulfate is reversed
back to lead and lead oxide during each charge cycle. The remaining 15% -
20% remains as lead sulfate and the longer it remains so, the harder it is
to reverse. The accumulation of lead sulfate will eventually lead to
battery failure. Even periodic equalization will not totally remove the
most stubborn remnants. And frequent equalization has its own issues in
terms of damage to the battery.
Boats that frequently tie up to shore power can overcome this because the
duration on shore power will enable the charger to complete the float
stage and hopefully reverse all of the accumulated lead sulfate. But what
about cruisers who routinely stay at anchor for days on end, then make a
short hop to another anchorage?
The float stage must be maintained for several hours to remove the last
vestiges of lead sulfate. Battery engineers make the assumption that the
charging regime is done without simultaneously depleting the same battery
bank with an ongoing load. Unfortunately this is the norm for cruising
boats.
One solution might be to split the house bank and bring one half up to
float charge with wind or solar panels while the other half is used to
support hotel load on board. This may or may not be workable, depending on
how big the hotel load is.
Has anyone developed a good routine?
best regards
Arild
Arild,
Once a week, I leave the genset running until the entire bank (I've
got all 12 8D's in parallel when I do this) is fully charged. That
takes a few hours longer than the usual ~80% charge. I gives me a
chance to fully fill the water tank and run bed linen and towels and
the like through the washer and dryer. I do this even if I've been
underway a fair bit, as the alternator on my John Deere isn't as smart
about charging as my Xantrex. The process is just a lot quicker if the
engine alternator has the bank mostly charged.
One of these days I'm going to switch out the alternator with a
Balmar or similar that has an external smart charger that optimally
handles Lifeline AGM's, and that would eliminate the need for the long
genset run. We never sit at anchor for more than a week without moving.
And a couple of times a year, I Condition my AGM's (Lifeline's term
for what is called Equalization on flooded cells) by holding the bank
at 31.2v for 8 hours to recover any lost capacity. That's tricky as
all the other 24v loads and lights need to be turned off for that
period.
John
On Dec 7, 2008, at 1:46 PM, 2elnav@netbistro.com wrote:
John Marshall wrote
We cook with propane, and rarely fire up the electric oven, although
we do microwave a bit.
In warmish weather, our major current drain is refrigeration. In
winter, in the PNW with short days and heating needs, lights and
heating dominate.
REPLY
Once we get past the obvious issues of sea keeping ability, hull
strength
and integrity; the biggest ongoing issue facing all cruising boats
is how
to manage the available energy resources. This ranges from the most
fuel
efficient cruising speed to getting the maximum return on genset run
time.
When fuel was cheap and refueling stations plentiful, it was not as
much
of an issue. The new reality seems to be, fuel is getting much more
expensive and many of the smaller fuel docks may not continue to
stay in
business.
It has for a long time been considered a given that you stop the
generator
when the battery is recharged to about 80% of full charge. Once you
get
into the later stages of absorbtion and float charge, the genset is
no
longer efficient in terms of amp hour output for fuel consumed input.
I do not propose to question thi, but the one thing about this
practice
that is a downside is the fact not all of the lead sulfate is reversed
back to lead and lead oxide during each charge cycle. The remaining
15% -
20% remains as lead sulfate and the longer it remains so, the harder
it is
to reverse. The accumulation of lead sulfate will eventually lead to
battery failure. Even periodic equalization will not totally remove
the
most stubborn remnants. And frequent equalization has its own issues
in
terms of damage to the battery.
Boats that frequently tie up to shore power can overcome this
because the
duration on shore power will enable the charger to complete the float
stage and hopefully reverse all of the accumulated lead sulfate. But
what
about cruisers who routinely stay at anchor for days on end, then
make a
short hop to another anchorage?
The float stage must be maintained for several hours to remove the
last
vestiges of lead sulfate. Battery engineers make the assumption that
the
charging regime is done without simultaneously depleting the same
battery
bank with an ongoing load. Unfortunately this is the norm for cruising
boats.
One solution might be to split the house bank and bring one half up to
float charge with wind or solar panels while the other half is used to
support hotel load on board. This may or may not be workable,
depending on
how big the hotel load is.
Has anyone developed a good routine?
best regards
Arild
http://lists.samurai.com/mailman/listinfo/passagemaking-under-power
To unsubscribe send email to
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UNSUBSCRIBE and nothing else in the subject or body of the message.
Passagemaking Under Power and PUP are trademarks of Water World
Productions, formerly known as Trawler World Productions.
There is a downside to long, slow charging, at least when it comes to
AGM batteries, which would be a big issue with solar. Lifeline (and I
assume this applies to all low-resistance AGM's) is very specific that
for repetitive charging, you should charge at a rate of 0.2 x battery
bank capacity in amp/hours, otherwise you'll lose capacity over time.
So you get clobbered on both ends if you aren't careful. Here's the
link:
http://www.lifelinebatteries.com/manual.pdf
In my case, when I parallel all 12 batteries, I've got 1530 amp/hours
capacity at 24v (charge relays automatically connect thruster
batteries to house bank during charge). Per Lifeline, I should have an
initial NET (after house loads) charge current of AT LEAST 306 amps,
with a maximum of 5x capacity -- a staggering 7650amps (you really
can't charge these batteries too fast). Between my Xantrex 4KW
inverter/charger and two additional Mastervolt chargers (each rated at
50amps at 24v), I can't get above 220 amps at 24v.
Guess I need to add yet another 100 amp at 24v charger. Good news is
that its more load for the genset (makes it more efficient) and
shortens bulk recharge time.
But that said, I've never met anyone who could achieve a 320amp charge
rate at 24v on their boat (640 amps at the usual 12v). That's ~8kw,
net of house loads and charger efficiency losses -- probably need 10KW
with only light house loads on the DC system just to charge.
It also says that bringing the house bank back up with my engine-
driven 170amp at 24v alternator is a recipe for short battery life and
short alternator life. Which says I have to do the bulk charge with
the Genset even if I'm underway. Not many people think of doing that
when pulling out of an anchorage with a half-depleted house bank.
And clearly, if you go to solar charging, stick with old-fashioned
flooded cell batteries. You can't get enough amperage for a large AGM
bank unless your whole boat is covered in solar cells. Even then...
Arild is right... energy management gets to be a huge deal if you need
a lot of power. And the idea of split battery banks sounds better all
the time.
John Marshall
On Dec 7, 2008, at 1:46 PM, 2elnav@netbistro.com wrote:
John Marshall wrote
We cook with propane, and rarely fire up the electric oven, although
we do microwave a bit.
In warmish weather, our major current drain is refrigeration. In
winter, in the PNW with short days and heating needs, lights and
heating dominate.
REPLY
Once we get past the obvious issues of sea keeping ability, hull
strength
and integrity; the biggest ongoing issue facing all cruising boats
is how
to manage the available energy resources. This ranges from the most
fuel
efficient cruising speed to getting the maximum return on genset run
time.
When fuel was cheap and refueling stations plentiful, it was not as
much
of an issue. The new reality seems to be, fuel is getting much more
expensive and many of the smaller fuel docks may not continue to
stay in
business.
It has for a long time been considered a given that you stop the
generator
when the battery is recharged to about 80% of full charge. Once you
get
into the later stages of absorbtion and float charge, the genset is
no
longer efficient in terms of amp hour output for fuel consumed input.
I do not propose to question thi, but the one thing about this
practice
that is a downside is the fact not all of the lead sulfate is reversed
back to lead and lead oxide during each charge cycle. The remaining
15% -
20% remains as lead sulfate and the longer it remains so, the harder
it is
to reverse. The accumulation of lead sulfate will eventually lead to
battery failure. Even periodic equalization will not totally remove
the
most stubborn remnants. And frequent equalization has its own issues
in
terms of damage to the battery.
Boats that frequently tie up to shore power can overcome this
because the
duration on shore power will enable the charger to complete the float
stage and hopefully reverse all of the accumulated lead sulfate. But
what
about cruisers who routinely stay at anchor for days on end, then
make a
short hop to another anchorage?
The float stage must be maintained for several hours to remove the
last
vestiges of lead sulfate. Battery engineers make the assumption that
the
charging regime is done without simultaneously depleting the same
battery
bank with an ongoing load. Unfortunately this is the norm for cruising
boats.
One solution might be to split the house bank and bring one half up to
float charge with wind or solar panels while the other half is used to
support hotel load on board. This may or may not be workable,
depending on
how big the hotel load is.
Has anyone developed a good routine?
best regards
Arild
http://lists.samurai.com/mailman/listinfo/passagemaking-under-power
To unsubscribe send email to
passagemaking-under-power-request@lists.samurai.com with the word
UNSUBSCRIBE and nothing else in the subject or body of the message.
Passagemaking Under Power and PUP are trademarks of Water World
Productions, formerly known as Trawler World Productions.
A point of clarification. I was only thinking of solar as a trickle charge
to top up the battery bank in float stage. There is no way you can
achieve anywhere near a good bulk rate with solar. The boat cannot support
enough square footage area of solar panels.
There is another good reason for the split bank concept. If you cannot
provide enough charge current to get above the 0.2 X battery capacity A-H
capacity then reducing the bank size while bulk charging may be the only
way. Leece-Neville use to make a wonderful 300 Amp @ 24V alternator. They
still provide data sheets on the Prestolite website but the product line
(VLF) is now listed as being discontinued.
I have one of these monsters and I know of a few more surplus units.
You may also be able to find one of the bigger rebuild shops with reman
units in stock.
However, there is another way. The trucking industry uses 160 amp
Leece-Neville alternators - at least on the older (pre 2000) trucks. Some
clever mounting using jack shafts and pillow bearings can provide you with
a 2X 150A = 300 Amp charging plant that can be driven by a coaxial flex
coupling and drive shaft.
John also wrote:
"That's ~8kw, net of house loads and charger efficiency losses --
probably need 10KW with only light house loads on the DC system just to
charge".
REPLY
Quite true, but that is still only about 15 HP of power from the engine.
If you have a 25HP or larger wing engine, its quite doable.
regards
Arild
---------------------- original message --------------------------
There is a downside to long, slow charging, at least when it comes to
AGM batteries, which would be a big issue with solar. Lifeline (and I
assume this applies to all low-resistance AGM's) is very specific that
for repetitive charging, you should charge at a rate of 0.2 x battery
bank capacity in amp/hours, otherwise you'll lose capacity over time.
So you get clobbered on both ends if you aren't careful. Here's the
link:
http://www.lifelinebatteries.com/manual.pdf
In my case, when I parallel all 12 batteries, I've got 1530 amp/hours
capacity at 24v (charge relays automatically connect thruster
batteries to house bank during charge). Per Lifeline, I should have an
initial NET (after house loads) charge current of AT LEAST 306 amps,
with a maximum of 5x capacity -- a staggering 7650amps (you really
can't charge these batteries too fast). Between my Xantrex 4KW
inverter/charger and two additional Mastervolt chargers (each rated at
50amps at 24v), I can't get above 220 amps at 24v.
Guess I need to add yet another 100 amp at 24v charger. Good news is
that its more load for the genset (makes it more efficient) and
shortens bulk recharge time.
But that said, I've never met anyone who could achieve a 320amp charge
rate at 24v on their boat (640 amps at the usual 12v). That's ~8kw,
net of house loads and charger efficiency losses -- probably need 10KW
with only light house loads on the DC system just to charge.
It also says that bringing the house bank back up with my engine-
driven 170amp at 24v alternator is a recipe for short battery life and
short alternator life. Which says I have to do the bulk charge with
the Genset even if I'm underway. Not many people think of doing that
when pulling out of an anchorage with a half-depleted house bank.
And clearly, if you go to solar charging, stick with old-fashioned
flooded cell batteries. You can't get enough amperage for a large AGM
bank unless your whole boat is covered in solar cells. Even then...
Arild is right... energy management gets to be a huge deal if you need
a lot of power. And the idea of split battery banks sounds better all
the time.
John Marshall
o;?
Although an interesting concept -- I tend to agree with Ken that there is no
perfect passagemaker; at least there is no perfect passagemaker for a group
as large and diverse as this list. I am also a little troubled by the
emphasis on "cheap," but I assume that you really mean inexpensive -- but
even that is something oftentimes in the eye of the beholder.
If you were going to pursue any meaningful PPM discussion I think that you
would need to travel on at least a couple of different paths, defined by
whether this is a cruising couple (retired; full time live aboard; still
working; "young;" taking a couple of years off and combinations thereof)
and a general total budget (500k; 1M). Of course that would take us down
several different paths and quickly become unmanageable.
Let's face it, the "needs" and rational "wants" of a couple that plan to
retire and live aboard while cruising the world are far different than those
of a young couple that plan to take a year or two to cruise and then return
to the "normal" world. The calculus is also far different between a couple
and a single male.
When I started designing our current build, Michael Kasten first had us try
to decide what we absolutely wanted out of the boat, what we would like, how
we planned to use the boat and for how long. We then had to decide a
general, very broad price range. These generated an approximate size and
much of our layout and equipment needs. The fine tuning was a series of
compromises and tradeoffs, with the cost gorilla always lurking over each
decision. For example, we have two kids of different genders and it was
very important for Debbie and I to make sure that the boat had three
separate sleeping areas so that the kids could always visit for holidays
regardless of where we were. We absolutely insisted on a covered aft deck
area, that we have enjoyed immensely on our '78 Gulfstar. To us, those
design "musts" took precedent over almost every other competing aspects of
the design. To others, these would be a meaningless waste of space.
All along the way there were cost and "gizmo" tradeoffs. Our decision to
have twin keels and paravanes was influenced, in some measure, by the cost
of active stabilizers as opposed to the passive method. Also, we were
worried about the long-term reliability of active stabilizers and the spotty
performance during the Nordhavn North Atlantic Rally pushed us away from the
more complex technology and toward the simpler and less expensive means of
roll stabilization.
Arild is correct, also, that designs have a natural time lapse and
technology marches forward even after your design decision has been made.
The reliability of active stabilizers has improved greatly since the NAR and
that was probably a significant learning event for the builders and the
stabilizer manufacturers. Our decision to use twin keels had long since
been, however (truth be told, though, I still think I would have shied away
from the extra expense and additional complexity).
Now, it ain't over with the design either.
I will never forget my first visit to YachtSmiths International -- who we
eventually selected to build our dream -- when Brian Smyth (one of the two
guys that runs YS) told me that there would undoubtedly be changes along the
way as the boat went from 2D drawings to 3D metal, wood, glass and equipment
I confess I did not believe him, but he turned out to be quite correct.
Once the boat begins to take shape and you start climbing on and in it,
suddenly little design alterations that never occurred to you appear out of
thin air and, sometimes, what looked great on paper doesn't seem to be what
you envisioned initially. Being in the space can be quite different than
simply imagining it. A good. Flexible and imaginative builder is an
absolute must.
Truth be told, you would be hard pressed to start designing a group PPM with
a specific cost figure. Kasten could really only give us general guidelines
and said that it would really need to await submission of the plans to
builders to get their cost estimates. Even then, when we solicited bids,
the results varied widely, by 80+ percent.
For Debbie and I, we wanted something that was safe at sea, could handle a
long passage, and had systems that leaned toward the simple and easy to
repair as opposed to the more complex and difficult to repair. We also
wanted some measure of luxury as well. I know that many can live without
air conditioning at night. My hat is off to you, but here in Florida doing
so for many many nights out of the year would make a night out on the hook
miserable. Some like camping; we don't. We hate the all night generator,
though, so we wanted the ability to run the air conditioner in the master
cabin overnight on battery/inverter power alone. We ended up with a huge
battery bank (1700 amp hours @ 24v) to meet our design needs. And dang it,
I confess that I want a TV in each stateroom and lots of speakers to play
high quality, loud music whenever I wanted to throughout the boat. No one
needs air conditioning, flat screens, and a great sound system, but I want
the boat to be a home, not just a way to get across the Atlantic.
We chose aluminum, but steel is probably less expensive (but has a lower
resale value and must be painted).
You really have to think about how you will live on the boat -- particularly
if it will be home for 15+ years. While there are some neat design and
efficiency reasons to have a 6:1 L/W ration, in reality I think that is
unreasonable, unless you are going to end up with a very long boat, which
will be expensive almost regardless of what you put inside. At 6:1 L/W a 50
foot boat will only be 8.33 feet wide -- and a lot less than that below deck
That severely restricts your living space and its usability, especially if
the boat is intended as your long term home and not just a mechanism to take
a year cruise. You would need a 72' boat just to get a 12 foot beam.
We are probably better off discussing systems as opposed to the perfect boat
Any systems discussion will allow anyone thinking about a build, purchase,
or major refit to decide how any particular design feature will fit into
their concept of a perfect passagemaker. There can be more than one PPM,
after all.
By the way -- no small part of what will be our PPM was the result of input
from the T&T list (our initial design predates PUP). Heck, in the end, I
owe the electrical design for our PPM to Arild, who I eventually hired to
fine tune what Kasten originally specified. Arild, of course, came right
from our midsts. The T&T forum and now PUP has been, and continues to be, a
huge resource for me, even now, as my systems are finalized. As such, I
suspect that if anyone is in the same "what do I design/build" stage that I
was in a four years ago, a discussion of passagemaker systems could only
help.
Alan Wagner
Building 53' Aluminum Passagemaker
Kasten designed / YachtSmiths Built
-------Original Message-------
From: hannu venermo
Date: 12/7/2008 2:43:49 AM
To: passagemaking-under-power@lists.samurai.com
Subject: Re: [PUP] PPM in general - what should it be ?
This makes a PPM;
6:1 L/W ratio
Heavy
Standardisation in mechanical engineering.
Steel
Redundancy in mechanical aspects as much as practical
All components are extremely fit for purpose and chosen for long-term
reliability and capacity
Can you drive the 300a model off a single belt? Not sure what my
current drive belt is called, but its an inch or so wide. If so, it
might be possible to replace my current Leece-Neville 170A model with
the 300A. Tks for heads up on the spec sheet. I'm guessing a used unit
might be floating around out there somewhere.
John
On Dec 7, 2008, at 5:21 PM, 2elnav@netbistro.com wrote:
A point of clarification. I was only thinking of solar as a trickle
charge
to top up the battery bank in float stage. There is no way you can
achieve anywhere near a good bulk rate with solar. The boat cannot
support
enough square footage area of solar panels.
There is another good reason for the split bank concept. If you
cannot
provide enough charge current to get above the 0.2 X battery
capacity A-H
capacity then reducing the bank size while bulk charging may be the
only
way. Leece-Neville use to make a wonderful 300 Amp @ 24V alternator.
They
still provide data sheets on the Prestolite website but the product
line
(VLF) is now listed as being discontinued.
I have one of these monsters and I know of a few more surplus units.
You may also be able to find one of the bigger rebuild shops with
reman
units in stock.
However, there is another way. The trucking industry uses 160 amp
Leece-Neville alternators - at least on the older (pre 2000) trucks.
Some
clever mounting using jack shafts and pillow bearings can provide
you with
a 2X 150A = 300 Amp charging plant that can be driven by a coaxial
flex
coupling and drive shaft.
John also wrote:
"That's ~8kw, net of house loads and charger efficiency losses --
probably need 10KW with only light house loads on the DC system
just to
charge".
REPLY
Quite true, but that is still only about 15 HP of power from the
engine.
If you have a 25HP or larger wing engine, its quite doable.
regards
Arild
---------------------- original message --------------------------
There is a downside to long, slow charging, at least when it comes to
AGM batteries, which would be a big issue with solar. Lifeline (and I
assume this applies to all low-resistance AGM's) is very specific
that
for repetitive charging, you should charge at a rate of 0.2 x battery
bank capacity in amp/hours, otherwise you'll lose capacity over time.
So you get clobbered on both ends if you aren't careful. Here's the
link:
http://www.lifelinebatteries.com/manual.pdf
In my case, when I parallel all 12 batteries, I've got 1530 amp/hours
capacity at 24v (charge relays automatically connect thruster
batteries to house bank during charge). Per Lifeline, I should have
an
initial NET (after house loads) charge current of AT LEAST 306 amps,
with a maximum of 5x capacity -- a staggering 7650amps (you really
can't charge these batteries too fast). Between my Xantrex 4KW
inverter/charger and two additional Mastervolt chargers (each rated
at
50amps at 24v), I can't get above 220 amps at 24v.
Guess I need to add yet another 100 amp at 24v charger. Good news is
that its more load for the genset (makes it more efficient) and
shortens bulk recharge time.
But that said, I've never met anyone who could achieve a 320amp
charge
rate at 24v on their boat (640 amps at the usual 12v). That's ~8kw,
net of house loads and charger efficiency losses -- probably need
10KW
with only light house loads on the DC system just to charge.
It also says that bringing the house bank back up with my engine-
driven 170amp at 24v alternator is a recipe for short battery life
and
short alternator life. Which says I have to do the bulk charge with
the Genset even if I'm underway. Not many people think of doing that
when pulling out of an anchorage with a half-depleted house bank.
And clearly, if you go to solar charging, stick with old-fashioned
flooded cell batteries. You can't get enough amperage for a large AGM
bank unless your whole boat is covered in solar cells. Even then...
Arild is right... energy management gets to be a huge deal if you
need
a lot of power. And the idea of split battery banks sounds better all
the time.
John Marshall
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Can you drive the 300a model off a single belt? Not sure what my
current drive belt is called, but its an inch or so wide. If so, it
might be possible to replace my current Leece-Neville 170A model with
the 300A. Tks for heads up on the spec sheet. I'm guessing a used unit
might be floating around out there somewhere.
John
REPLY - off list
These require twin Vee belts or a 10 rib serpentine belt.
a pulley profile chart is also availabel on the Prestolite website.
The surplus units I am referring to are now in the Bellingham WA area. We
got them in new condition still in the original shipping crate.
Mounting is slightly different than what you might be accustomed to. The
mount is a saddle, not your conventional J-180 mount. Last time I looked
all relevant data sheets including mechanical mounting dimensions was
stil on the Prestolite website.
These units were originally intended for locomotive use and were designed
with an end bell having a 3" duct collar for cooling air to be ducted in
from a blower. The highway coach industry also picked up on these.
There is a technical note on the Prestolite website dealing with how to
convert a D-50 oil cooled alternator to one of these air cooled units. On
the busses the alternator is mounted on a PTO shaft in the transmission
and this is also a very dirty area subject to road dirt and flying water
and road salt.
Here again the ducted cooling air is a great way to keep the dirt out of
the alternator. For marine use you can also just dispense with the end
bell and just mount a screen to keep anything from contacting the wire
termination on the diode block.
For USCG use these were de-rated to 200 amps continuous use. The 300 amp
rating is good for about 5 hours running time at maximum amperage.
Cheers
Arild
Tks, Arild... I'll do the research and see how feasible it will be to
mount.
John
On Dec 7, 2008, at 10:23 PM, 2elnav@netbistro.com wrote:
Can you drive the 300a model off a single belt? Not sure what my
current drive belt is called, but its an inch or so wide. If so, it
might be possible to replace my current Leece-Neville 170A model with
the 300A. Tks for heads up on the spec sheet. I'm guessing a used
unit
might be floating around out there somewhere.
John
REPLY - off list
These require twin Vee belts or a 10 rib serpentine belt.
a pulley profile chart is also availabel on the Prestolite website.
The surplus units I am referring to are now in the Bellingham WA
area. We
got them in new condition still in the original shipping crate.
Mounting is slightly different than what you might be accustomed to.
The
mount is a saddle, not your conventional J-180 mount. Last time I
looked
all relevant data sheets including mechanical mounting dimensions
was
stil on the Prestolite website.
These units were originally intended for locomotive use and were
designed
with an end bell having a 3" duct collar for cooling air to be
ducted in
from a blower. The highway coach industry also picked up on these.
There is a technical note on the Prestolite website dealing with how
to
convert a D-50 oil cooled alternator to one of these air cooled
units. On
the busses the alternator is mounted on a PTO shaft in the
transmission
and this is also a very dirty area subject to road dirt and flying
water
and road salt.
Here again the ducted cooling air is a great way to keep the dirt
out of
the alternator. For marine use you can also just dispense with the end
bell and just mount a screen to keep anything from contacting the wire
termination on the diode block.
For USCG use these were de-rated to 200 amps continuous use. The 300
amp
rating is good for about 5 hours running time at maximum amperage.
Cheers
Arild
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To unsubscribe send email to
passagemaking-under-power-request@lists.samurai.com with the word
UNSUBSCRIBE and nothing else in the subject or body of the message.
Passagemaking Under Power and PUP are trademarks of Water World
Productions, formerly known as Trawler World Productions.