I've mentioned this befo you should simply parallel the bank and
install a small starting battery. If you want it to be high quality
and "idiot proof" and a battery combiner (the smaller ones are cheap.
Why invest in an "emergency" starter when the same money give you a
proper solution?

BTW, the small Yanmar will *usually* starts with under 5 seconds of
cranking, but it isn't self bleeding, so it can get balky if the line
gets dirty or airbound. I just started my two engines after winter
layup - one fired quickly, but the other took about 30 seconds of
cranking. My point is that in real life problems always come in
groups - the morning your battery dies could also be the morning the
fuel filter clogs. Why rely on a pack of D cells that cost the same
as a proper battery?


Roger Long wrote:
It's amazing how complicated simple things are when you start thinking
about them.

A little research in Calder's book shows that he, at least, considers
bilge pumps on the battery side common.

But..

I've already decided to run both my batteries as close to parallel as
possible to minimize the depth of the discharge cycles and get maximum
life out of the expensive AGM cells. This goes against the
conventional wisdom of always maintaining a dedicated starting
battery. I'm going against the grain because:

a.. This is a sailboat and I will not be helpless if the engine
doesn't start. I've cruised in boats with no engine at all.
b.. The engine can be hand started, at least in warm weather.
c.. I'm going to be mostly daysailing and short cruising this year.
d.. I have very minimal ship's service loads so it is unlikely that
I'll run the batteries flat.
e.. I can start this little engine with a portable emergency
battery. It's even been done with a handful of flashlight batteries.
So, if I want a dead ship except for the bilge pump, I have to decide
which battery to use. That means that a long run of pumping with the
charger off, as could happen with the boat unattended in a storm,
would drain one battery down. I also would only have half the battery
capacity for bilge pumping under the same circumstances. That is not
ideal. Worse, if one battery did die, I would have to get into the
panel and switch the bilge pump. That's not good.

I guess that, for now at least, I'll just leave things as they are
with the bilge pump wired into the bus. That means leaving the switch
on "Both" when putting the boat away and being sure to turn everything
except the bilge pump off.

A good solution for my situation would be two bilge pumps, one on each
battery. That would provide redundancy. It should be simple to run a
second line and another through hull in this boat. I'll just wire them
into the same float switch. I'm going to take a look tomorrow. We're
doing a lot of through hull work anyway and we'll have the equipment
right there to punch one in above the waterline.

The ramifications just go on. I just realized that the bilge
discharge fitting is 3/4 and the pump hose is 1 /18. That means there
is a reducer somewhere. That's a kludge I'd better track down. That
would be another reason to go to two pumps of the same total capacity.

Roger Long wrote:
That's an excellent point. Exactly the kind of insight that prompted
my post.

The cables in this case are about half an inch in diameter and three
feet long. With just 10 amps of charging current per group 24 battery
I agree that it won't be a problem. I cleaned up the battery
connections bright and shiny when I put the batteries in and I'll do
the other connections when I install the charger.

I'm glad you understand the significance of this issue, and it sounds
like you won't have a problem. Single 0 (1/0) cable should handle 10
Amps for over 100 feet with less than a 2% drop.

However, readers should be aware that a 100 Amp current will have a 2%
voltage drop in 10 feet of single 0, and 14 feet of double 0. this
will be a few tenths of a volt, enough to give a distorted reading of
the charge state.

In my case I have both a 100 Amp alternator and a 100 Amp shore
charger. The shore charger is about 3 feet of 2/0 away, but the
alternator is 15 feet. The next time I running it with a high rate
I'll have to test the battery post voltage so see if its running
higher than expected.

On Sat, 07 May 2005 21:44:17 GMT, "Roger Long"
wrote:


I've already decided to run both my batteries as close to parallel as
possible to minimize the depth of the discharge cycles and get maximum
life out of the expensive AGM cells. This goes against the
conventional wisdom of always maintaining a dedicated starting
battery.

Modern electronic equipment can cause some annoyance/inconvenience
when powered from the same battery as used to start the engine.

When you start the engine, the battery voltage will drop significantly
- this may be enough to turn off depth sounders and other things that
have "soft" (electronic) power switches, and may cause
microprocessor-based equipment to reset - your GPS may have to start
from scratch re-acquiring satellites, and the radar will have to go
through the 90 second warm-up routine again.

Whether this is a serious problem, minor annoyance, or insignificant
will depend on the equipment on board, the circumstances, and on the
user....



--
Peter Bennett, VE7CEI
peterbb4 (at) interchange.ubc.ca
new newsgroup users info : http://vancouver-webpages.com/nnq
GPS and NMEA info: http://vancouver-webpages.com/peter
Vancouver Power Squadron: http://vancouver.powersquadron.ca

I actually agree with all your points and it's probably the advice I'd
give someone else. However, I'm opting for simplicity and economy
over the certainty of being able to start the engine in all
circumstances. I'm not even going to invest in the emergency battery.
The proper place for that, as you say, is in a box hooked up with the
combiner, etc.

My emergency propulsion for this year at least, will be good ground
tackle and the willingness to wait for a wind. I'm going to try hand
starting. If it does prove impossible I'll invest in a more
sophisticated system. This is also a boat with no major electrical
loads. I'll also be upgrading a lot of stuff before starting long
cruises. This will be a duff around close to home and get to know the
boat summer. I'll probably be spending a lot more time working on the
systems than sailing. Aside from saving money, I'll have a much
better idea at the end of the summer exactly what the boat needs and
how I want to set up a more complex system.

Even on a cruise Downeast, sailing in to anchor and rowing ashore to
pick up a $40 car battery for a jump start wouldn't be a major
emergency in this part of the world. Another two or three hundred
dollars could be spent on much more critical things at this point than
avoiding the slight possibility of that exercise.

--

Roger Long



"Jeff" wrote in message
...
I've mentioned this befo you should simply parallel the bank and
install a small starting battery. If you want it to be high quality
and "idiot proof" and a battery combiner (the smaller ones are
cheap. Why invest in an "emergency" starter when the same money give
you a proper solution?

BTW, the small Yanmar will *usually* starts with under 5 seconds of
cranking, but it isn't self bleeding, so it can get balky if the
line gets dirty or airbound. I just started my two engines after
winter layup - one fired quickly, but the other took about 30
seconds of cranking. My point is that in real life problems always
come in groups - the morning your battery dies could also be the
morning the fuel filter clogs. Why rely on a pack of D cells that
cost the same as a proper battery?

After all the crap with the Capn and other trolls, it's nice to have a
discussion going on here where solid information comes back.

My electronics outfit is pretty minimalist and the starting loads
about as small as they get. Starting from the two battery bank
shouldn't produce much drop with this little engine. This is
confirmed by someone who has been running the same kind of boat for
ten years this way.

However, before installing radar or a hard mounted GPS, I will
consider that adding a dedicated starting battery is an essential part
of the installation.

On this boat, I think I would go with the smaller size battery used in
aircraft. If they will start the 320 cubic inch, 160 hp, engine in my
172, they ought to get this little diesel going.

--

Roger Long



"Peter Bennett" wrote in message
news.com...
On Sat, 07 May 2005 21:44:17 GMT, "Roger Long"
wrote:


I've already decided to run both my batteries as close to parallel
as
possible to minimize the depth of the discharge cycles and get
maximum
life out of the expensive AGM cells. This goes against the
conventional wisdom of always maintaining a dedicated starting
battery.

Modern electronic equipment can cause some annoyance/inconvenience
when powered from the same battery as used to start the engine.

When you start the engine, the battery voltage will drop
significantly
- this may be enough to turn off depth sounders and other things
that
have "soft" (electronic) power switches, and may cause
microprocessor-based equipment to reset - your GPS may have to start
from scratch re-acquiring satellites, and the radar will have to go
through the 90 second warm-up routine again.

Whether this is a serious problem, minor annoyance, or insignificant
will depend on the equipment on board, the circumstances, and on the
user....



--
Peter Bennett, VE7CEI
peterbb4 (at) interchange.ubc.ca
new newsgroup users info : http://vancouver-webpages.com/nnq
GPS and NMEA info: http://vancouver-webpages.com/peter
Vancouver Power Squadron: http://vancouver.powersquadron.ca

Roger, I like your parallel bilge pump idea, but I'm not sure how you can
run this through one float switch as I've never heard of a DPST bilge
switch. Is there such an animal available? Without it you will have
difficulty isolating one battery bank from the other.

I'm quite new to the sailing game and can't address many of your points, but
I've risked my life and family in many other kinds of self-reliant endeavors
and I've found that it is most important to rely on YOUR style of operation,
not just "general practices". The row-in-for-a-quick-battery approach had
me in stitches; not because I was laughing at you, but because it resembled
my own unconventional, but practical, style of risk assessment: If you're
not vulnerable, why be defensive!
Padeen

"Roger Long" wrote in message
...
I actually agree with all your points and it's probably the advice I'd
give someone else. However, I'm opting for simplicity and economy
over the certainty of being able to start the engine in all
circumstances. I'm not even going to invest in the emergency battery.
The proper place for that, as you say, is in a box hooked up with the
combiner, etc.

My emergency propulsion for this year at least, will be good ground
tackle and the willingness to wait for a wind. I'm going to try hand
starting. If it does prove impossible I'll invest in a more
sophisticated system. This is also a boat with no major electrical
loads. I'll also be upgrading a lot of stuff before starting long
cruises. This will be a duff around close to home and get to know the
boat summer. I'll probably be spending a lot more time working on the
systems than sailing. Aside from saving money, I'll have a much
better idea at the end of the summer exactly what the boat needs and
how I want to set up a more complex system.

Even on a cruise Downeast, sailing in to anchor and rowing ashore to
pick up a $40 car battery for a jump start wouldn't be a major
emergency in this part of the world. Another two or three hundred
dollars could be spent on much more critical things at this point than
avoiding the slight possibility of that exercise.

--

Roger Long



"Jeff" wrote in message
...
I've mentioned this befo you should simply parallel the bank and
install a small starting battery. If you want it to be high quality
and "idiot proof" and a battery combiner (the smaller ones are
cheap. Why invest in an "emergency" starter when the same money give
you a proper solution?

BTW, the small Yanmar will *usually* starts with under 5 seconds of
cranking, but it isn't self bleeding, so it can get balky if the
line gets dirty or airbound. I just started my two engines after
winter layup - one fired quickly, but the other took about 30
seconds of cranking. My point is that in real life problems always
come in groups - the morning your battery dies could also be the
morning the fuel filter clogs. Why rely on a pack of D cells that
cost the same as a proper battery?

Great info, Larry, I've been convinced about the dual battery switches since
I came up with the idea myself. : ), and I really like your light indicator
application. As a commercial electrician I sometimes received odd looks
when I announced the implementation of my most sophisticated and reliable
measuring instrument - a 100w bulb in a pigtail - which told me more, in
many cases, than a Fluke o-scope.

But (and isn't there always a but), I don't understand your reasoning about
the "little wires" in a charger. Yes, I'm aware of the Wal-mart mentality
of cranking these units out with as little copper as possible (try jumping
your car at -50 with a set of Walmart cables! Zip-cord has a new
application.), but since no current (to speak of) passes through these
during a hard start, and assuming correctly gauged wires to the battery
switch, why would the charger react badly to a normal start? This is, one
must assume, a start from a healthy battery.
Padeen


"Larry W4CSC" wrote in message
...
"Doug Dotson" dougdotson@NOSPAMcablespeedNOSPAMcom wrote in
:

Bilge pump should not be wired though a battery switch. If you have a
switch that even has a "both" position, then there is a better way.
House bank
should be unique with a separate starting battery. A switch to
parallel the starting bank to the house bank in the case of an
emergency is a good idea.

DOug



Great advise, Doug. Lionheart has two battery switches, side-by-side.
One
selects which L-16 house battery bank, normally left in BOTH and the other
selects which battery (starting or house or both) is connected to the
diesel starter, normally left in STARTing battery. The house connection
simply connects the starting switch to the common of the house switch.
Set
both switches to BOTH parallels everything in the boat, the ultimate
jumper
cables..(c; Of course, you can switch everything to OFF to unpower it all
except the permanently-connected bilge pumps and battery chargers(one for
house, one for starting). Bilge pumps and chargers connect through their
own safety fuse block located on the side of the house battery boxes,
directly connected BOTH NEGATIVE AND POSITIVE. Bilge pumps do NOT have an
OFF position, which I consider REALLY STUPID in any boat! Stalled bilge
pump blows the fuse, which has a neat 12V bulb across the fuse for EASY
IDENTIFICATION. It'll light up the space until you press the new fuse
into
the holder. Why more don't do that remains a mystery to me.

As to connecting the chargers upline from the battery posts, I'm against
it. The chargers have enough trouble measuring the battery's voltage
because they are wired so cheap by the manufacturers...i.e. such little
wires. Every time a load current passes through the wires and corrosion
from the battery switch, where the charger would be connected, to the
battery, this voltage drop would be measured as an increased drop in
battery voltage by the charger. This screws up the charging cycles.
Nope,
connect the chargers directly to the battery being charged without load
current carrying wires in the path.

For safety, Lionheart has a 100A fuse in the jumper link between the 6V
batteries in series, one on each bank. Any shorts, except directly across
one battery's terminals, would simply blow the fuse, not burn the boat to
the waterline. 200A on #2 is a safe limit with the switch in BOTH and
Amel
has master breakers where we connect our wiring to the original boat
French
wiring. Starting the Perkins through one 100A fuse may blow it if the
engine were locked, but doesn't when it is "normal" as we tried it.

If there's any power left....we can crank it...(c;

Any 12/24V fuse or breaker can have a trouble light on it, easy. Just
wire
an indicator light ACROSS the fuses in all circuits. The current through
the load that blew the fuse will light the bulb. If the bulb is full
brightness, it's a pretty good indication the load has a short to negative
that needs to be cleared before you blow more fuses or retrip the breaker.
I like the way it shows me what fuse/breaker is tripped while we're all
sitting in the dark or in a dark engine room. I use bright red indicator
lights that give me plenty of light to replace the fuse, but of course
they
go out or go dim when you clear the short. Just turn on the load and
they'll light back up so you can see the fuse holders.....cheap at any
Ratshack.

Given a sufficiently sized cable, the electrical equivalency will be equal.

"engsol" wrote in message
...
On Sat, 07 May 2005 11:00:11 GMT, "Roger Long"
wrote:

I'm about to install an onboard battery charger.

Is there any reason why the charging leads can not go to the ends of
the battery cables at the selector switch instead of snaking into the
box and being put on the terminals? This would be easier and neater
and minimize the chance of things getting switched at battery change.

When we put the batteries in, the yard made a good point. Switching
one battery end for end so that either the two + or - terminals are
side by side greatly minimizes the chance of a massive short if
something gets across the terminals while the system is on.
Everything should be dead whenever the box cover is off but this is
real life and both boating and aviation are a good place for a belt
and suspenders approach.

Roger, the only concern I'd have is that chargers rely on knowing
the "real" battery voltage. If you have load on the batteries while they
are being charged, the extra voltage drop due to "remote"
sensing might not be to your abvantage. Having said that, I suspect
that with clean terminals and big cables the problem would be minimal.
Norm B

Good point, Jeff. Thanks. I'm quite familiar with 120 through 480 volt
drops, but it's nice to be reminded how dramatic 12v drops can be.
Padeen


"Jeff" wrote in message
...
Roger Long wrote:
That's an excellent point. Exactly the kind of insight that prompted
my post.

The cables in this case are about half an inch in diameter and three
feet long. With just 10 amps of charging current per group 24 battery
I agree that it won't be a problem. I cleaned up the battery
connections bright and shiny when I put the batteries in and I'll do
the other connections when I install the charger.

I'm glad you understand the significance of this issue, and it sounds
like you won't have a problem. Single 0 (1/0) cable should handle 10
Amps for over 100 feet with less than a 2% drop.

However, readers should be aware that a 100 Amp current will have a 2%
voltage drop in 10 feet of single 0, and 14 feet of double 0. this
will be a few tenths of a volt, enough to give a distorted reading of
the charge state.

In my case I have both a 100 Amp alternator and a 100 Amp shore
charger. The shore charger is about 3 feet of 2/0 away, but the
alternator is 15 feet. The next time I running it with a high rate
I'll have to test the battery post voltage so see if its running
higher than expected.

Roger,
You'd make it easier for us, and yourself, if you could identify those
cables with a gauge # and class, rather than a diameter. Wire insulation
varies dramatically with its class, allowing a range of conductor size
within a specific measurement. For instance, XLP (insulation designation)
may be as much as .02-.05in larger than THHN.
Please don't take my post as criticism; I'm merely suggesting an alternative
to wire descriptions by diameter.


Roger Long" wrote in message
...
That's an excellent point. Exactly the kind of insight that prompted
my post.

The cables in this case are about half an inch in diameter and three
feet long. With just 10 amps of charging current per group 24 battery
I agree that it won't be a problem. I cleaned up the battery
connections bright and shiny when I put the batteries in and I'll do
the other connections when I install the charger.

--

Roger Long


"engsol" wrote in message
...
On Sat, 07 May 2005 11:00:11 GMT, "Roger Long"
wrote:

Roger, the only concern I'd have is that chargers rely on knowing
the "real" battery voltage. If you have load on the batteries while
they
are being charged, the extra voltage drop due to "remote"
sensing might not be to your abvantage. Having said that, I suspect
that with clean terminals and big cables the problem would be
minimal.
Norm B