The generator starting battery outboard of the
generator’s aft end.
Engine starting/house battery
bank engine room stbd.
4G2: DC Batteries
The batteries on this boat are not just one, big all-purpose battery. To have
redundancy, there are actually several “banks” of batteries assigned different tasks. This table
outlines the batteries on the boat, their locations, their charging sources, and what they power:
Battery Name
Location
Charging Source
Use
Stbd Engine &
House Batteries
Engine room outboard of engine.
Starting battery aft-most of the
three.
Engine Starting: Engine alternator and
ship’s battery charger.
House: Engine alternator and inverter.
Operate engine starter and
provide house voltage.
Generator Battery
Engine room aft to starboard of
generator
Generator’s own alternator and ship’s
battery charger
Start generator’s engine
Port Engine &
House Batteries
Engine room outboard of engine.
Starting battery aft-most of the
three.
Engine Starting: Engine alternator and
ship’s battery charger.
House: Engine alternator and inverter.
Operate engine starter and
provide house voltage.
Thruster Battery
Under forward berth
Ship’s battery charger.
Operate bow thruster
A “starting bank” consisting of a 12-volt battery is
used for
starting each main engine only
. That way, we won’t run it down playing
the stereo, for instance, and then be unable to start an engine. This
battery is charged by the main engine’s “stock” alternator when running,
or by the battery charger if it is on when there is shore power or the
generator is running.
In the event of a low engine-starting battery, the operator can
start the other engine or the generator to recharge it.
Note: If it takes more than two attempts to start an engine, turn off its
sea water valve to avoid
water-locking the
engine until it starts; then be sure to turn it back
on!
Another 12-volt battery (in the engine room starboard
aft alongside the Genset) provides 12 volts for starting the
generator, charged by the generator’s own alternator if it is
running, or by the battery charger if it is not and there is shore
power.
A “house bank” consisting of parallel-wired 12-volt
batteries provides power for all the pumps, interior and
exterior lights, horns, navigation and radio gear, etc., the
boat’s “house”. They are charged by the alternators on each
main engine and, when there is shore power or the generator is running, by the inverter if it is
on.
Finally, be aware that the generator system on
Hele Mai
is arranged to automatically
start and charge the batteries whenever battery voltage falls below 11.9 volts. This requires
that, when not on shore power, the shore power/generator selector switch be on “Gen”.
Section 4G: Electrical Systems, DC 4.17