I've asked about boat batteries before but now we're planning to launch
next weekend and it's time to buy them. So see if this makes sense or if
I'm wrong anywhe

SITUATION:

The boat is a 22 foot 1958 Chris Craft (that we've been restoring for
the past 2.5 years). Engine is a in-line / straight 6 cylinder 130
horsepower and 320 cubic inches. It has a generator with voltage regulator.

The electrical setup I've created calls for two
12 volt batteries. They are on an A/B/ALL
switch with a battery-combiner (BC) between them.
Normally I plan to run with the switch in
just the "A" or "B" position. So when the engine
is running the BC will combine the batteries and
both will be charged. When the engine stops and
we are drawing current for light & such, only one
battery will be supplying power. If that one got
drained we could switch to the other to restart
the boat.

The items that might be drawing power on the boat
a Small bulbs for bow & stern lights, Small bulbs
and LED lights in the cockpit & cuddy/cabin areas,
Instrument back-lighting, Depth Finder. Maybe
something like a radio and/or GPS plugged into
a 12 volt outlet. Also there are two 1100 GPH
bilge pumps, but I don't expect them to run much.

Use: We are in the Northeast and will probably trailer
the boat, using is every other weekend or so. There could
be times we're on vacation with it in a slip for a week
at a time or possibly sleeping on the boat for a night
while moored near some island or something.


QUESTIONS:

TYPE OF BATTERY: I know that Gel or Absorbent Glass Matt
(AGM) are supposed to be better. But for this application
where these is not much vibration, no need to mount the
batteries in any position except "normal" and where the
battery may not get 100% proper storage (ie no trickle
charger all winter) I'm thinking the extra cost is not
worth it. I'm thinking just use regular flooded batteries.

SIZE will be group 24. I believe the space that I have
for the batteries (under the passenger seat) will take
two Group 24 batteries.

CCA/MCA: I really don't know what size Cold Cranking Amps
or Marine Cranking Amps is necessary/good to turn over the
engine I have. I'm guessing that anything in around about 550
is fine. If I can get more for not much more $$ than that's what
I'll do.

RESERVE CAPACITY: I really don't have much draw on these batteries
so pretty much whatever the RC rating is will be fine for my use.

TYPE: I'm thinking that Dual-Purpose is the way to go. It is possible
that I'd draw a batter down when occasionally sleeping on the boat
overnight and Starting batteries don't like that very much.

TWO OF THE SAME: Since they will be charging in tandem (together)
it's best to have two of the same. Also, I'll sometimes have the switch
on "A" and sometimes on "B" so both get approximately the same
useage pattern.

BUYING:
+ Check the date manufactured on the battery and try to get ones that are
less than 3 months old.
+ Try to get them with a longer free-replacement period as this is a good
sign of quality
+ Watch out because replacement are sometimes pro-rated and based on the
LIST price, not retail.

WHERE TO BUY:
?? CostCo ??
?? Specific Brands to look for OR avoid ??


Thanks for reading and for any help or comments!
Gary

SIZE will be group 24. I believe the space that I have
for the batteries (under the passenger seat) will take
two Group 24 batteries.

Make sure you allow sufficient room for battery boxes, and go with the largest
batteries that will fit the space you describe. If you can use Group 27's, that
would be better.


TYPE: I'm thinking that Dual-Purpose is the way to go. It is possible
that I'd draw a batter down when occasionally sleeping on the boat
overnight and Starting batteries don't like that very much.

Why not just go with deep cycle? That way you're more likely to get the heavy
plates that will stand up to severe discharge. A deep cycle battery is "dual
purpose", in so much as that if the CCA rating is sufficient for the engine you
will do
*no* harm to the deep cycle battery using it to power the starter. As you have
already determined, you will damage a "starting" battery with a series of deep
discharge cycles.

WHERE TO BUY:
?? CostCo ??
?? Specific Brands to look for OR avoid ??



I like my Rolls batteries a lot. Surette is the same battery, but made on the
other side of the US/CAN border. Ten year warranty, with the first seven years
non-prorated, full replacement.

OTOH, you could afford to buy cheap batteries a few times for what you'd spend
for Rolls or Surette. Pay now, or pay later.......but if you only intend to
keep the boat a year or two before trading up the average quality cheapies are
probably the way to go.

Gould,

Thanks for the good comments. I will consider if Group 27 will fit. I'm a
little
confused by the deep-cycle vs. dual use. If deep-cycle will be OK for
starting
then why ever buy/make a dual-use?


OTOH, you could afford to buy cheap batteries a few times for what you'd
spend
for Rolls or Surette. Pay now, or pay later.......but if you only intend
to
keep the boat a year or two before trading up the average quality cheapies
are
probably the way to go.


We've worked 2.5 years on this boat. We've got more into her than they sell
for.
It was a labor of love and I expect that I'll keep that boat until I'm dead.
The memories
of my father shaping parts, the work he and I and my brother did, the
support from
the rest of our families & friends, well, it just wouldn't be the same on
another boat.

Not to say I wouldn't buy another boat TOO

I guess I'm generally of the mind of keeping the batteries somewhat on the
cheap side.
Not that I want them to fail, but it seems batteries in boats go every
couple years
anyway. Probably because while I try to store them properly over the winter,
I
can't get down there to "top them off" and and I don't like the idea of a
trickle
charger being connected for weeks at a time without me stopping by to make
sure everything is OK.

Again, Thanks for the comments!
Gary

Thanks for the good comments. I will consider if Group 27 will fit. I'm a
little
confused by the deep-cycle vs. dual use. If deep-cycle will be OK for
starting
then why ever buy/make a dual-use?

You might compare the CCA and the scale weight of a dual purpose battery with
both a starting battery and a deep cycle. I haven't done so, but the comparison
might be interesting.

Starting batteries use thinner plates to create a greater area of exposure to
electrolytes. This results in a greater number of CCA in a given battery size.
Downside, those thin plates disintegrate faster during severe
discharge/recharge cycles..

Deep cycle batteries use heavier plates, at the expense of some CCA. The
heavier plates will withstand serious recharging with less damage than the
lighter plates in starting batteries.

Dual purpose could be anything. A starting battery with such a short warranty
or high margin that the mfg figures he can afford to replace a few under
warranty. A "medium duty" battery slightly heavier than a starting battery but
not as rugged as a deep cycle. A genuine deep cycle battery labeled "dual
purpose" to rake in a few sales from folks who think they have to have a
different battery technology for starting the engine than for running DC loads.
Who knows?

Gary Warner wrote:
The electrical setup I've created calls for two
12 volt batteries. They are on an A/B/ALL
switch with a battery-combiner (BC) between them.

It would be simpler, cheaper, and more foolproof to simply have each
battery on a key switch. The A/B/Both/Off switches create all sorts of
problems from dead batteries to fried alternators.


Normally I plan to run with the switch in
just the "A" or "B" position. So when the engine
is running the BC will combine the batteries and
both will be charged. When the engine stops and
we are drawing current for light & such, only one
battery will be supplying power. If that one got
drained we could switch to the other to restart
the boat.

Exactly!


QUESTIONS:

TYPE OF BATTERY: I know that Gel or Absorbent Glass Matt
(AGM) are supposed to be better. But for this application
where these is not much vibration, no need to mount the
batteries in any position except "normal" and where the
battery may not get 100% proper storage (ie no trickle
charger all winter) I'm thinking the extra cost is not
worth it. I'm thinking just use regular flooded batteries.

Agree. I don't see enough advantage in your usage to get AGMs, unless
the boatteries are in an inaccessible place and will be difficult to
service.

Also, you don't mention it but are you putting in a hard wired charger?
Definitely get & use a 3-stage smart charger no matter how you rig it.



SIZE will be group 24. I believe the space that I have
for the batteries (under the passenger seat) will take
two Group 24 batteries.

Might be too small. If you're using 2 dual purpose instead a starting &
a deep cycle, then you're getting less cranking amps and less amp-hours
capacity.

http://www.cs.ucf.edu/~matt/leadacid/guide.html


CCA/MCA: I really don't know what size Cold Cranking Amps
or Marine Cranking Amps is necessary/good to turn over the
engine I have. I'm guessing that anything in around about 550
is fine. If I can get more for not much more $$ than that's what
I'll do.

Agreed. This is one case where more is better.


RESERVE CAPACITY: I really don't have much draw on these batteries
so pretty much whatever the RC rating is will be fine for my use.

TYPE: I'm thinking that Dual-Purpose is the way to go. It is possible
that I'd draw a batter down when occasionally sleeping on the boat
overnight and Starting batteries don't like that very much.

neither do dual purpose, for that matter deep cycle batteries get rather
upset if you discharge them past 50%


TWO OF THE SAME: Since they will be charging in tandem (together)
it's best to have two of the same. Also, I'll sometimes have the switch
on "A" and sometimes on "B" so both get approximately the same
useage pattern.

If you were oversizing the batteries so that there wasn't risk of
damaging or hard sulfating them starting the engine, I'd say fine. But
since you're limited in size I'd suggest getting a starting battery and
a deep cycle and marking the switches as such. You might also consider
getting two dual purpose batteries and then finding a place for two golf
cart batteries somewhere else for house loads.



BUYING:
+ Check the date manufactured on the battery and try to get ones that are
less than 3 months old.
+ Try to get them with a longer free-replacement period as this is a good
sign of quality
+ Watch out because replacement are sometimes pro-rated and based on the
LIST price, not retail.

Good. I bought two Exide Gr-31 batteries that were approx 6 months on
the slef and they are not really satisfactory. If you can buy dry
batteries and have the vendor fill & charge them, that'd be better too.
Only a battery store will do this though.

Fair Skies
Doug King

Thanks Doug & John H for your comments & thoughts!

Got mine at walmart, wired in parallel.


"Gary Warner" wrote in message
...

I've asked about boat batteries before but now we're planning to launch
next weekend and it's time to buy them. So see if this makes sense or if
I'm wrong anywhe

SITUATION:

The boat is a 22 foot 1958 Chris Craft (that we've been restoring for
the past 2.5 years). Engine is a in-line / straight 6 cylinder 130
horsepower and 320 cubic inches. It has a generator with voltage
regulator.

The electrical setup I've created calls for two
12 volt batteries. They are on an A/B/ALL
switch with a battery-combiner (BC) between them.
Normally I plan to run with the switch in
just the "A" or "B" position. So when the engine
is running the BC will combine the batteries and
both will be charged. When the engine stops and
we are drawing current for light & such, only one
battery will be supplying power. If that one got
drained we could switch to the other to restart
the boat.

The items that might be drawing power on the boat
a Small bulbs for bow & stern lights, Small bulbs
and LED lights in the cockpit & cuddy/cabin areas,
Instrument back-lighting, Depth Finder. Maybe
something like a radio and/or GPS plugged into
a 12 volt outlet. Also there are two 1100 GPH
bilge pumps, but I don't expect them to run much.

Use: We are in the Northeast and will probably trailer
the boat, using is every other weekend or so. There could
be times we're on vacation with it in a slip for a week
at a time or possibly sleeping on the boat for a night
while moored near some island or something.


QUESTIONS:

TYPE OF BATTERY: I know that Gel or Absorbent Glass Matt
(AGM) are supposed to be better. But for this application
where these is not much vibration, no need to mount the
batteries in any position except "normal" and where the
battery may not get 100% proper storage (ie no trickle
charger all winter) I'm thinking the extra cost is not
worth it. I'm thinking just use regular flooded batteries.

SIZE will be group 24. I believe the space that I have
for the batteries (under the passenger seat) will take
two Group 24 batteries.

CCA/MCA: I really don't know what size Cold Cranking Amps
or Marine Cranking Amps is necessary/good to turn over the
engine I have. I'm guessing that anything in around about 550
is fine. If I can get more for not much more $$ than that's what
I'll do.

RESERVE CAPACITY: I really don't have much draw on these batteries
so pretty much whatever the RC rating is will be fine for my use.

TYPE: I'm thinking that Dual-Purpose is the way to go. It is possible
that I'd draw a batter down when occasionally sleeping on the boat
overnight and Starting batteries don't like that very much.

TWO OF THE SAME: Since they will be charging in tandem (together)
it's best to have two of the same. Also, I'll sometimes have the switch
on "A" and sometimes on "B" so both get approximately the same
useage pattern.

BUYING:
+ Check the date manufactured on the battery and try to get ones that are
less than 3 months old.
+ Try to get them with a longer free-replacement period as this is a good
sign of quality
+ Watch out because replacement are sometimes pro-rated and based on the
LIST price, not retail.

WHERE TO BUY:
?? CostCo ??
?? Specific Brands to look for OR avoid ??


Thanks for reading and for any help or comments!
Gary

"DSK" wrote in message
.. .
Gary Warner wrote:
The electrical setup I've created calls for two
12 volt batteries. They are on an A/B/ALL
switch with a battery-combiner (BC) between them.

It would be simpler, cheaper, and more foolproof to simply have each
battery on a key switch. The A/B/Both/Off switches create all sorts of
problems from dead batteries to fried alternators.


Normally I plan to run with the switch in
just the "A" or "B" position. So when the engine
is running the BC will combine the batteries and
both will be charged. When the engine stops and
we are drawing current for light & such, only one
battery will be supplying power. If that one got
drained we could switch to the other to restart
the boat.

Exactly!


QUESTIONS:

TYPE OF BATTERY: I know that Gel or Absorbent Glass Matt
(AGM) are supposed to be better. But for this application
where these is not much vibration, no need to mount the
batteries in any position except "normal" and where the
battery may not get 100% proper storage (ie no trickle
charger all winter) I'm thinking the extra cost is not
worth it. I'm thinking just use regular flooded batteries.

Agree. I don't see enough advantage in your usage to get AGMs, unless
the boatteries are in an inaccessible place and will be difficult to
service.

Also, you don't mention it but are you putting in a hard wired charger?
Definitely get & use a 3-stage smart charger no matter how you rig it.



SIZE will be group 24. I believe the space that I have
for the batteries (under the passenger seat) will take
two Group 24 batteries.

Might be too small. If you're using 2 dual purpose instead a starting &
a deep cycle, then you're getting less cranking amps and less amp-hours
capacity.

http://www.cs.ucf.edu/~matt/leadacid/guide.html


CCA/MCA: I really don't know what size Cold Cranking Amps
or Marine Cranking Amps is necessary/good to turn over the
engine I have. I'm guessing that anything in around about 550
is fine. If I can get more for not much more $$ than that's what
I'll do.

Agreed. This is one case where more is better.


RESERVE CAPACITY: I really don't have much draw on these batteries
so pretty much whatever the RC rating is will be fine for my use.

TYPE: I'm thinking that Dual-Purpose is the way to go. It is possible
that I'd draw a batter down when occasionally sleeping on the boat
overnight and Starting batteries don't like that very much.

neither do dual purpose, for that matter deep cycle batteries get rather
upset if you discharge them past 50%


TWO OF THE SAME: Since they will be charging in tandem (together)
it's best to have two of the same. Also, I'll sometimes have the switch
on "A" and sometimes on "B" so both get approximately the same
useage pattern.

If you were oversizing the batteries so that there wasn't risk of
damaging or hard sulfating them starting the engine, I'd say fine. But
since you're limited in size I'd suggest getting a starting battery and
a deep cycle and marking the switches as such. You might also consider
getting two dual purpose batteries and then finding a place for two golf
cart batteries somewhere else for house loads.



BUYING:
+ Check the date manufactured on the battery and try to get ones that
are
less than 3 months old.
+ Try to get them with a longer free-replacement period as this is a
good
sign of quality
+ Watch out because replacement are sometimes pro-rated and based on the
LIST price, not retail.

Good. I bought two Exide Gr-31 batteries that were approx 6 months on
the slef and they are not really satisfactory. If you can buy dry
batteries and have the vendor fill & charge them, that'd be better too.
Only a battery store will do this though.

Fair Skies
Doug King


Hard to get a nice setup with just the key switches. And my alternator has
survived since 1991 with a Guest 1/2/off switch. 351W Ford motor. I run 2
batteries and use a starting battery in #1 and a dual purpose in #2. Run
the electronics off #2 with a key switch to shut off power to the
electronics and a battery combiner from West Marine to charge the #2
battery. Then I just run the dual battery switch to #1 and turn on the
other switch to run the electronics. If #1 is bad, I can then switch to #2
for starting. Just did this 2 weeks ago, as #2 battery was bad, and only
had $2.69 of warranty left. Running the electronics off their own battery
prevents a couple of problems. Running down the starting battery, the
electronics do not cycle from low power when starting, and the EMF kickback
from the starter / solenoid is isolated from the the electronics, and saves
them.
Bill

And my alternator has
survived since 1991 with a Guest 1/2/off switch.

My understanding is that what can kill an alternator is if the Alt
is putting out power and you switch from, say, #1 to #2. At that
moment when you switch there is no battery connected to the
charging system to take the power thus creating a momentary
surge in power. Some switches are "make-before-break" so
they make the connection to the #2 battery BEFORE breaking
the connections to the #1. (or whichever way you are switching).

But these better type switches can look exactly like the cheaper
type. You have to check the part number (or study it's design
and operation) to determine which type you have.

"DSK" wrote in message
.. .

Also, you don't mention it but are you putting in a hard wired charger?
Definitely get & use a 3-stage smart charger no matter how you rig it.

On such a smally boat with such low electrical draw and only weekend
use do I really need/want a charger? Won't my generator take care of
charging up the batteries?

Other question: I do have a good home based battery charger. It has
both a full charge & trickle charge setting. But I see that trickly charging
all winter is going to kill the battery. So are my choices are basically as
follows ??

A: Charge it when taking it out, then leave it all winter
B: Go to the shop every 2 or 4 weeks and charge it for a while
C: Buy a "smart" or "float" charger and leave that running


And is it really OK to leave a smart charger running and connected to
a battery for weeks at a time without checking on it? The thought
of that just makes me a little nervous.