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four, reducing it to #4
wire, which is 0.360
(23/64) inches in di-
ameter, about half the
diameter of the aver-
age pinky. Once again,
for these reasons, the
argument for 24 volts
is strong indeed
aboard both new and
refit vessels.
In addition to the wire
girth and heft advan-
tages 24-volt systems
afford, there are sev-
eral other advantages
that are worth consid-
ering when making
this decision. Typically,
24-volt equipment is
more rugged because
the designers know it
will often be used in
severe or commercial
service (remember, many military small vessels are 24 volt,
as well as commercial craft). Additionally, 24-volt motors for
pumps, fans and blowers run cooler and hence last longer.
Halogen and incandescent lamps also run cooler and last
longer when designed for and operated with 24-volt service.
Many new electronics, VHFs, SSBs and radars in particular,
are designed to operate at any voltage between 11 and 30
volts. In the case of the radar, these units operate with
higher efficiency at 24 rather than 12 volts. As a rule of
thumb, it’s generally safe to assume that if a piece of electri-
cal or electronic gear is designed to operate on 24 volts, it’s
being used aboard military and commercial craft and as a
result it will be long lasting and is constructed of high quality
A Composite System, 12 and 24 Volts
Wiring a vessel for 24 volts is relatively straightforward. It
must be pointed out, however, that virtually no recreation
vessel is wired solely for 24 volts. As wide as, and continu
ously growing, the range of available 24-volt gear is, ther
will almost certainly be the need for 12-volt service aboar
It’s unlikely that you will be able to find a 24 volt cell pho
charger, hand held spot light or LP gas range igniter and
even if you could source these items in 24 volts, they wo
in all likelihood, be expensive and difficult to service or re
place in the event of a failure.
It is at this point that the vessel owner, boat builder or ref
yard must decide which gear will operate from 24 volts a
which gear will operate at 12 volts. Because the primary
of switching to 24 volts is to reduce wire size, it only stan
to reason that the highest ampere consumers and suppli
become strong candidates for 24-volt service. This includ
engine starters and alternators, bow and stern thruster,
Terminal Connections
Inverter/Charger Control Panel
Converter Breaker On Circuit Panel
Technician Working on a Battery Bank