[C320-list] Inadequate Dedicated Starting Battery

[Joe M]

Why 6 volt golf cart batteries and starting battery?

I have a pair of interstate 4d’s that do it all. The last set lasted 8
years.

Joe 2002 C320 hull #902

On Tue, Dec 7, 2021 at 9:58 AM Onat Dogruer <onatdogruer at gmail.com> wrote:

> Hi Bob,
>
> I tend to be very cautious before commenting without knowing how things are
> wired on someone's boat. However, the issue doesn't sound like a wire gauge
> issue. Typically older diesels have a higher cranking amp requirement,
> recommended 450-500CCA min starting battery. Our 1998 has a Yanmar 3GM30F
> and starting surge is 283A.  The start surge is only for a second or two
> and once the engine kicks up, alternator starts feeding back. Our setup is
> slightly similar; we have deep cycle golf cart batteries but we always
> start on that bank. Aux battery serves as an emergency start.
>
> G27 batteries should be more than adequate; even a good G24 will suffice.
> The issue might be the 'new' battery may not actually be in good
> condition.
> Alternatively, there may be a loose terminal (even a slight wobble will
> decrease output).  If I were facing this, I would start by the simplest and
> check the terminals, go over the wiring of the house bank and of the
> starting battery, and lastly may do a load-test on the starting battery.
>
>
>
> On Tue, Dec 7, 2021 at 8:54 AM Bob Hoyt <rehoyt at gmail.com> wrote:
>
> > I recently installed a Duralast G27 Marine battery to serve as a
> dedicated
> > starting battery to go with my house batteries (4 six-volt golf cart
> > batteries in series). I installed it just forward of the starboard
> battery
> > compartment. The existing cables are listed as 4 gauge, so I thought they
> > were adequate.
> > With a fully charged new battery and either a cold or warm engine, the
> > motor will barely turn over. With the battery selector on all, it starts
> > quickly. Is the group 27 battery underpowered or do I need to change the
> > wire from the battery to the main switch and wire from the switch to the
> > starter motor to 2 gauge? Thanks
> >
> > Bob Hoyt
> > Hull 154
> > 1994 C320 "Ikigai"
> > Pensacola, Fl
> >
> >
> > --
> >
> > *Robert (Bob) Hoyt MD, FACP, FAMIA, ABPM-CI*
> >
> > *Associate Clinical Professor, Department of Internal Medicine*
> >
> > *Virginia Commonwealth University*
> >
> > *Richmond, VA*
> >
> >
> > *CAPT (Ret) USN*
> >
> > InformaticsEducation.org  <http://InformaticsEducation.org>
> > rehoyt at gmail.com
> >
> > Cell: 850-384-5235
> >
>