I thinking about rotating both the hotel loads and the rather modest
starting loads between two deep cycle batteries so the get even
service. I'm aware of the problem with leaving them both connected if
there is an electrical leak or misjudgment about usage. This wouldn't
be as serious anyway as it would on a boat with an engine too big to
hand start.

--

Roger Long

On Tue, 11 Jan 2005 22:46:29 GMT, "Roger Long"
wrote:

I thinking about rotating both the hotel loads and the rather modest
starting loads between two deep cycle batteries so the get even
service. I'm aware of the problem with leaving them both connected if
there is an electrical leak or misjudgment about usage. This wouldn't
be as serious anyway as it would on a boat with an engine too big to
hand start.
Depends on how fast you need the engine started. Say there's a drunk
in a cigarette boat (or a tanker) bearing down on you. Or the wind
died and you have a 3 knot current pushing you on the rocks 50 yards
away. It's not that you have to have a motor ready for instant use to
go sailing. It's the situations you get into because you think you
have a motor ready for instant use.

That said, I sailed for more years than I'd care to remember using the
"rhythm system" for batteries as you describe. I did flatline the
system a couple of times by forgetting to switch from BOTH after
charging but it never got me in any trouble I couldn't get out of.
Regardless, I now have an idjit-proof system I'm much happier with.

Oh, and don't forget, batteries run other things than starters. Bilge
pumps, for example.
__________________________________________________ __________
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/

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



"Glen "Wiley" Wilson" wrote in
message ...
On Tue, 11 Jan 2005 22:46:29 GMT, "Roger Long"
wrote:

I thinking about rotating both the hotel loads and the rather modest
starting loads between two deep cycle batteries so the get even
service. I'm aware of the problem with leaving them both connected
if
there is an electrical leak or misjudgment about usage. This
wouldn't
be as serious anyway as it would on a boat with an engine too big to
hand start.
Depends on how fast you need the engine started. Say there's a
drunk
in a cigarette boat (or a tanker) bearing down on you. Or the wind
died and you have a 3 knot current pushing you on the rocks 50 yards
away. It's not that you have to have a motor ready for instant use
to
go sailing. It's the situations you get into because you think you
have a motor ready for instant use.

That said, I sailed for more years than I'd care to remember using
the
"rhythm system" for batteries as you describe. I did flatline the
system a couple of times by forgetting to switch from BOTH after
charging but it never got me in any trouble I couldn't get out of.
Regardless, I now have an idjit-proof system I'm much happier with.

Oh, and don't forget, batteries run other things than starters.
Bilge
pumps, for example.
__________________________________________________ __________
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:

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 02:27:05 GMT, Skip wrote:

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.

Dual batteries are working fine for me on an Atomic 4 gas engine, and
the system is simple, if not idiot proof. As insurance for those times
I may be an idiot, I carry a "booster pack" which is a sealed battery
complete with jumper cable style clamps and all the appropriate
switching, available at automotive suppliers for around US$50. Light,
cheap, simple and I can use it to boost my car in the winter.

Ryk

If your engine has a compression release, it can be started using a bunch
of D-cells.

"Ryk" wrote in message
...
On Wed, 12 Jan 2005 02:27:05 GMT, Skip wrote:

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.

Dual batteries are working fine for me on an Atomic 4 gas engine, and
the system is simple, if not idiot proof. As insurance for those times
I may be an idiot, I carry a "booster pack" which is a sealed battery
complete with jumper cable style clamps and all the appropriate
switching, available at automotive suppliers for around US$50. Light,
cheap, simple and I can use it to boost my car in the winter.

Ryk

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

Glowplugs, etc are a feature of indirect injected engines. Many
smaller diesels are direct injected and do not require glowplugs. My
Perkins 85HP will start almost instantly even with temps below freezing.

Doug
s/v CAllista

"Me" wrote in message
...
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