4G4: DC Battery Switches
The boat is equipped with a small panel of battery switches
mounted in the engine room on the forward bulkhead. Battery switches
for the engine starting and house batteries are on this panel, along with
a switch to parallel them.
Easily accessed from the engine room,
these switches are also reachable through the door under the
companionway steps in the forward stateroom in an emergency.
Switches just to Starboard of Engine Room - Companionway Door
SWITCH
PURPOSE
Port
Connects Port Engine to the Starting Battery
Starboard
Connects Starboard Engine to the Starting Battery
Parallel
Pairs the Starting and House Batteries
Immediately above this panel is a box with two breakers, the house battery master breakers.
The “Main” breaker is for the House Battery supplying all the DC accessories. The other breaker,
“Spare”, is unused.
An Inverter main battery switch is just forward of the starboard engine at its outboard side.
A Generator starting battery switch is just aft of the port engine on the rear engine room
bulkhead.
The DC House Battery main switch is at the bottom of the DC Breaker panel.
(See page 4.15.)
4G5: DC Battery Combiner
The vessel has a “battery combiner” that works automatically to keep the house and starting
batteries charged all the time. If this electronic device sees any charging voltage on any battery such
as from a charger or an engine or generator alternator, then it combines the batteries electrically, this
applying this charging voltage to all of them. This is valuable because it is therefore combining all the
boat’s charging capacity to any battery that is not fully charged. Since the House Battery is most likely
to be discharged — it is used the most — the combiner brings it back to full charge most quickly, a
most desirable result only possible with such a combiner.
The combiner is also designed to “sense” if a battery has become seriously defective, such as
“shorted”, in which case it does not combine the batteries, lest a bad one ruin the good ones. An
amazing system!
Battery switches are above the inverter.
Note House master breakers top left.
Section 4G: Electrical Systems, DC 4.14