Roger Long wrote:

snip There are very inexpensive battery management and charging
systems now that charge the batteries while leaving them isolated from
each other for normal loads.



It seems Glen and I have gone down similar paths...
If I'm understanding him, both of us _suggest_ the same thing - keep
engine starting energy available in a starting battery.
It gives you both house batteries to draw down without hand starting.
It's not only about the 1-B-2 switch.
Go ahead , use one of those motorcycle size starting duty batteries
instead of another ball buster - you have the house batteries as backup
for hard starting (a second level contingency) if you ever need it.
Just get enough CCA for the job...
It's like buying a little insurance...
Three-way isolation is pretty straight forward - except for non-matching
battery banks with accelerated (smart) charging.

Or do what a large percentage of owners do - live with the dual-battery
discharge rules you suggest (and the outcomes).
As you know, you'll face lot's of compromise decisions as you finish her
out to your satisfaction (not ours).
You will probably live thru whatever decision you make as we all have up
to this point.

Skip

On Wed, 12 Jan 2005 00:53:58 GMT, "Roger Long"
wrote:

My outlook is probably effected somewhat by watching the motorcycle
size battery in my plane start the 160 HP, high compression, engine
briskly on even below zero days.

Not quite what I meant. I'm talking about how long it takes to hand
crank the engine if you manage to flatline both batteries, which you
eventually will do following the protocol you mentioned.

BTW the 1,2 Both switch is an anachronism that I'll be ditching as
soon as I can get the boat back to Maine and overhaul the whole
system.

Which was my point.
__________________________________________________ __________
Glen "Wiley" Wilson usenet1 SPAMNIX at world wide wiley dot com
To reply, lose the capitals and do the obvious.

Take a look at cpRepeater, my NMEA data integrator, repeater, and
logger at http://www.worldwidewiley.com/

"Roger Long" wrote in message
.. .
My outlook is probably effected somewhat by watching the motorcycle size
battery in my plane start the 160 HP, high compression, engine briskly on
even below zero days.

Most aircraft batteries (even if motorcycle size) are AGM or gel. High
energy density for their size. Also, I assume that you preheat your engine
on your aircraft prior to starting.. All aircraft I have piloted require
preheat prior to starting to minimize excessive wear while the oil
decides to be useful. So most aircraft engines are not actually started at
zero temps.

BTW the 1,2 Both switch is an anachronism that I'll be ditching as soon as
I can get the boat back to Maine and overhaul the whole system.

Agreed. An antiquated concept.

There are very inexpensive battery management and charging systems now
that charge the batteries while leaving them isolated from each other for
normal loads.

Not exacty inexpensive but worth it.

--

Roger Long


Doug
s/v Callista

In article ,
"Roger Long" wrote:

My outlook is probably effected somewhat by watching the motorcycle
size battery in my plane start the 160 HP, high compression, engine
briskly on even below zero days.

BTW the 1,2 Both switch is an anachronism that I'll be ditching as
soon as I can get the boat back to Maine and overhaul the whole
system. There are very inexpensive battery management and charging
systems now that charge the batteries while leaving them isolated from
each other for normal loads.

--

Roger Long

There is a BIG difference between a DIESEL engine and a Gasoline engine,
when starting in cold weather. Comparing the two is "Apples and Oranges"
A diesel has a higher Compression Ratio than a Gas engine. Gas
volitilizes at a much lower temp than diesel fuel. Gas engines have
Spark Plugs that ignite the fuel/air mixture, and provides the required
heat of ignition. In a diesel with no glowplugs the only heat generated
is the Heat of Compression, which takes a while to build in the cyl.
That's why they invented Glow Plugs, and Intake Air Manifold Heaters,
to heat the fuel/air past the ignition temp.

Me

In article ,
"Roger Long" wrote:

Is there any reason to consider using dual purpose or a one starting, one
deep cycle set up with a 20 hp Yanmar diesel? I would think the starting
loads on the small engine are low enough that two deep cycle batteries would
do fine.


Just about everything I've seen in the thread is correct, but I have a
couple of odd thoughts for you to consider.

We currently have 2 group 31s, about 230 total AH. Our 2GM20F will start
off a half-discharged group 27, so starting isn't a serious issue. Major
consumption is lights -- many, many lights -- as we're addicted to
reading and night sailing.

Our main problem has been that we motor too little. Usually, we've been
lucky to have even 50% charge.

----

Our last charter, the starting battery connected directly to the
alternator. The house battery was tied in via a simple on-off switch: On
to charge, off otherwise. That's not the best way to charge and it's
possible to drain all the batteries, but you can't fry the regulator.
-----

Last spring, we got a 12 watt solar charger which changed our habits
significantly. When we weekend, we're charged to 100% as we start out.

On our annual 3 week cruise around the Chesapeake, that little charger
satisfied our needs completely as long as we motored into a harbor every
few days. One morning, the battery was dead. A few hours of sun later,
we had enough charge to start.

I'll probably combine the two ideas next time I have to replace a
battery. Remaining 31 goes next to the engine, short leads. House bank
gets beefier, panel goes directly to it. Battery switch is almost always
off.

--
Jere Lull
Xan-a-Deux ('73 Tanzer 28 #4 out of Tolchester, MD)
Xan's Pages: http://members.dca.net/jerelull/X-Main.html
Our BVI FAQs (290+ pics) http://homepage.mac.com/jerelull/BVI/

"Jere Lull" wrote in message
...
In article ,
"Roger Long" wrote:

Is there any reason to consider using dual purpose or a one starting,
one
deep cycle set up with a 20 hp Yanmar diesel? I would think the
starting
loads on the small engine are low enough that two deep cycle batteries
would
do fine.


Just about everything I've seen in the thread is correct, but I have a
couple of odd thoughts for you to consider.

We currently have 2 group 31s, about 230 total AH. Our 2GM20F will start
off a half-discharged group 27, so starting isn't a serious issue. Major
consumption is lights -- many, many lights -- as we're addicted to
reading and night sailing.

Our main problem has been that we motor too little. Usually, we've been
lucky to have even 50% charge.

----

Our last charter, the starting battery connected directly to the
alternator. The house battery was tied in via a simple on-off switch: On
to charge, off otherwise. That's not the best way to charge and it's
possible to drain all the batteries, but you can't fry the regulator.
-----

Last spring, we got a 12 watt solar charger which changed our habits
significantly. When we weekend, we're charged to 100% as we start out.

On our annual 3 week cruise around the Chesapeake, that little charger
satisfied our needs completely as long as we motored into a harbor every
few days. One morning, the battery was dead. A few hours of sun later,
we had enough charge to start.

I'll probably combine the two ideas next time I have to replace a
battery. Remaining 31 goes next to the engine, short leads. House bank
gets beefier, panel goes directly to it. Battery switch is almost always
off.



Ahoy Jere!
Have you moved or am I mistaken? I thought you were in the SanD area. If
you're the same guy, I was seeking information about finding moorage a
couple of years ago around the south bay etc. Never made it to SD though,
but am now in middle Tennessee. Boy the sailing is sure different here!

Rico

In article ,
"Rico" wrote:

Ahoy Jere!
Have you moved or am I mistaken? I thought you were in the SanD area. If
you're the same guy, I was seeking information about finding moorage a
couple of years ago around the south bay etc. Never made it to SD though,
but am now in middle Tennessee. Boy the sailing is sure different here!

No, have only sailed the Right coast, mostly Chesapeake Bay.

--
Jere Lull
Xan-a-Deux ('73 Tanzer 28 #4 out of Tolchester, MD)
Xan's Pages: http://members.dca.net/jerelull/X-Main.html
Our BVI FAQs (290+ pics) http://homepage.mac.com/jerelull/BVI/