[C320-list] Inadequate Dedicated Starting Battery

[Troy Dunn]

Couple of nagging issues here.    The original 4AWG cables were for the
charger and windlass.   You can look in my gallery for the original DC
wiring diagram as well as a decent idea of a good way to set up for your
current configuration.   Trying to start your Yanmar engine with a 4AWG
cable and by who knows what path is robbing your starter of power due to
voltage drop/sag.    Even when you are successfully cranking you aren’t
doing it well and that will lead to premature starter failure as well as
battery issues.   Upgrade to 1/0 cable which is really required for the
amps your starter is drawing.

Also if you are using this battery as a dedicated start battery then most
CCAs is the best way to go for deciding which battery to get.
Unfortunately it sounds like maybe your battery is wired through the
combine switch as a reserve battery not a start battery.   Sounds like
semantics but it isn’t.   If you have the normal 1/2/BOTH/OFF switch then
you are most likely just having your G27 battery hanging out in what you
think is full reserve use for your starter…but….your windless might (I say
might because you really need to understand why there are 4AWG cables on
the battery) still be wired to the G27.   That would mean that your G27 is
getting used every time you use that current sucking device at the bow of
your boat.   Now…if for instance you anchor all week, you think the battery
is hanging out…all the while you are actually hitting hard for juice coming
off anchor…then…you have a big problem if you aren’t a)switching to BOTH
while using your alternator or b) have an ACR.

Number 1 is a no brainer your starter can draw huge currents…especially
when it’s hard starting (the current goes up actually)   Your wire needs to
be sized to that current draw and 4AWG isn’t correct.

Number 2 is way more complicated with so many variables…you need more info,
maybe you are fine or could be fine with simple “operational work arounds”
(this is engineer lingo for we messed up the design because we didn’t
understand the requirements so…don’t do that…LOL)

FWIW

Troy Dunn
Hull #514 (Wonky Dog)