I'll let you know when I get the boat

My first two batteries are free, (and therefore probably minimum
quality) when the boat is delivered. Since this boat will seldom, if
ever, see shore power and often sail on and off its mooring, one of my
first projects will be a complete upgrade of the whole power system.
This will probably involve moving to sealed batteries in the bilge
since these boats are stern heavy and a bit tender. I'll also probably
put in a solar trickle system.

--

Roger Long



"DSK" wrote in message
...
Roger Long wrote:
I understand that but, is the load on a 20 hp diesel that you can
start by hand high enough to significantly reduce the life of the
battery?


What's the voltage drop when starting? Starting batteries can see
surges bring them down to as low as 8 volts and bounce back just
fine. DC batteries don't like this.

I'm not sure where the cut-off is, but if the starting load drops
your voltage down below 10, or maybe 10.5 (assuming that you've got
a good current path to starter & ground), then you might consider
staying with a start battery.

Fresh Breezes- Doug King

On Wed, 12 Jan 2005 12:24:16 GMT, "Roger Long"
wrote:
I'll let you know when I get the boat

My first two batteries are free, (and therefore probably minimum
quality) when the boat is delivered. Since this boat will seldom, if
ever, see shore power and often sail on and off its mooring, one of my
first projects will be a complete upgrade of the whole power system.
This will probably involve moving to sealed batteries in the bilge
since these boats are stern heavy and a bit tender. I'll also probably
put in a solar trickle system.

===========================================

With my last boat I used 6 volt golf cart batteries for both starting
and a house bank driving a large inverter. The engines were 350 hp,
454 cubic inch V8s, and they never had a problem cranking, even in
freezing weather.

"Scott Vernon" wrote in message
...
Yes, a deep cycle will start your Yanmar, but you are reducing the
life of the battery by doing so.

Not by enough that you would even notice it. A recreational boat
starts so seldom and a load of 80A isn't enough to do any harm.

There's a reason, other than marketing, why batteries are labeled
'starting' or 'deep cycle' or 'dual purpose'.
I believe the main difference is the thickness of the plates. Starter
batts, are built for short duration, high loads. DC are for less
load over a longer time period. DP are a compromise between the two.

All true.

Doug
s/v CAllista


--
Scott Vernon
Plowville Pa _/)__/)_/)_


"Roger Long" wrote in message
...
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.

--

Roger Long

"Doug Dotson" dougdotson@NOSPAMcablespeedNOSPAMcom wrote in message
...

"Scott Vernon" wrote in message
...
Yes, a deep cycle will start your Yanmar, but you are reducing the
life of the battery by doing so.

Not by enough that you would even notice it. A recreational boat
starts so seldom and a load of 80A isn't enough to do any harm.


Right, I agree. But, being in the MD area, I've got to consider
sometimes starting in cold weather and cranking more than usual.


--
Scott Vernon
Plowville Pa _/)__/)_/)_

Scott Vernon wrote:
"Doug Dotson" dougdotson@NOSPAMcablespeedNOSPAMcom wrote in message
...

"Scott Vernon" wrote in message
...

Yes, a deep cycle will start your Yanmar, but you are reducing the
life of the battery by doing so.

Not by enough that you would even notice it. A recreational boat
starts so seldom and a load of 80A isn't enough to do any harm.



Right, I agree. But, being in the MD area, I've got to consider
sometimes starting in cold weather and cranking more than usual.


Actually, I think the bigger issue is the non-starter loads. If the
boat has a fridge or other high house loads, you want to add house bank
capacity, which then makes it hard to do the "swap 1 & 2" trick. Once
you have dedicated banks it pays to use a proper starting battery.

OTOH, my previous boat had a finicky Westerbeke, which has a pre-heater,
and it never had a problem starting off a Surrette deep cycle.

I also live in the MD area (actually I live in MD proper) , and
"sometimes" isn't really a factor, and "cranking more than usual"
isn't either as long as it isn't the norm. I can start my engine at
freezing temps with maybe 5 revs rather than the normal 2. If your
engine requires alot of revs to start then a dedicated starting
battery is probably a good idea. But even so, 80A isn't a heavy load
for a decent deep cycle battery. I draw 50A to run the refrigeration
and 100A to run the microwave.

Doug
s/v Callista

"Scott Vernon" wrote in message
...

"Doug Dotson" dougdotson@NOSPAMcablespeedNOSPAMcom wrote in message
...

"Scott Vernon" wrote in message
...
Yes, a deep cycle will start your Yanmar, but you are reducing the
life of the battery by doing so.

Not by enough that you would even notice it. A recreational boat
starts so seldom and a load of 80A isn't enough to do any harm.


Right, I agree. But, being in the MD area, I've got to consider
sometimes starting in cold weather and cranking more than usual.


--
Scott Vernon
Plowville Pa _/)__/)_/)_

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.



Are you asking the proper question?
If you have deep discharge batteries for cruising power in lieu of
engine, then you might need to consider being practiced at starting by
hand lest you find yourself without adequate battery to run whatever
including starting the engine. If you have a small engine, keep a small
starting battery for the task... Many production boats in this area
(Great Lakes) have the dual battery configuration successfully, and
occasional white knuckles.

Skip

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/