[C320-list] Battery Bank Upgrade - Which starting battery??

[Jeff Hare]

Hi Alan,

   I'm not sure what the ABYC has to say about the fusing here, but
generally, there is no fuse in the starting circuit, so that probably
shouldn't be a concern as the cables are heavy and bolted securely at both
ends.  Other loads however are fused of course.

Also, my suggestion is to get the battery with the highest cranking amps
that conveniently fits your space.  I use an AGM starting battery with about
950 CCA.  The main reason is that it'll last longer if you're not drawing
anywhere close to its max amps during starting.  The other reason is that
should you end up having a fuel problem, you'll appreciate having a much
higher starting reserve on the shelf without fear of draining the starting
battery.

Finally, I recommend an automotive AGM because its more durable, recharges
faster, charges with the same settings you use for your main flooded battery
bank, and you'll never have to worry about checking the water, having it
freeze, or discharge over the winter.  It'll hold a full charge over the
winter without needing to keep it on trickle charge.  Mine was maybe $60
more than the regular automotive battery.  

Whatever you decide Don't get a combo- deep cycle/starting battery.  That
will not work well in this application.  Been there.

Cheers!
-Jeff

-----Original Message-----
From: c320-list-bounces at lists.catalina320.com
[mailto:c320-list-bounces at lists.catalina320.com] On Behalf Of Alan Goodman
Sent: Friday, March 18, 2011 4:02 PM
To: c320-list at lists.catalina320.com
Subject: [C320-list] Battery Bank Upgrade - Which starting battery??



I am in the midst of upgrading my battery bank following the instructions in
the forum archives.  FYI, based upon cost / benefit ($200 each) I installed
2 Interstate SRM-4D lead acid batteries for the house bank providing a
combined capacity of 410 Ah.  (I know, they are not a pure deep cycle
battery, but readily available without paying huge shipping charges)
I am ready to purchase the dedicated start battery.  I am looking at a Group
24 (11x 6 7/8 x 9 1/2 inch) lead acid rated at 800 CCA and 1000 MCA.
Looking at my Perkins shop manual, the required starting current is 540A.
Does this seem reasonable, or am I reading the spec sheet incorrectly?
Also, assuming 540A is correct, I have been looking for a fuse to install at
the battery "+" (Blue Sea MEGA SEA fuse block p/n 5001), but it seems that
300A is the maximum fuse (per Defender Catalog).  I think that this fuse
rating would be inadequate, any other suggestions?     Alan;  Hull #67;
Holland MI; launching last week of April or first week of May, weather and
ice dependent !!
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