Battery Isolators; Dual Battery Charging Systems - Mercury MerCruiser D2.8L D-Tronic Service Manual

SERVICE MANUAL NUMBER 22
8. Reconnect the wiring harness to the alternator. Coat terminals with liquid neoprene.
9. Connect battery cables to battery.

Battery Isolators

Dual Battery Charging Systems

NOTE: Mercury MerCruiser engines equipped with a 3-wire, belt driven alternator, can use
a battery isolator.
Battery isolators allow the addition of an auxiliary (second) battery to the Mercury MerCruis-
er electrical system. The auxiliary battery is primarily used as a power source for various
accessories installed on the boat. The battery isolator will allow the alternator to charge both
the cranking and auxiliary batteries at the same time while preventing accessories, con-
nected to the auxiliary battery, from drawing power from the cranking battery.
Mercury Marine does not manufacture any battery isolator systems. Battery isolators must
be bought from an outside manufacturer. Mercury Marine suggests following the manufac-
turer's instructions carefully.
IMPORTANT: Alternators used on Mercury MerCruiser engines ARE NOT equipped
with an isolation diode.
Follow battery isolator manufacturer's instructions for wire gauge. Battery isolator
installation must conform to BIA Low Voltage Wiring Standard No. 125-79.
90-860074--1 FEBRUARY 2002
a - Excitation Wire - PURPLE
b - Sensing Wire - RED or GREEN
c - Ground Wire - BLACK
d - Output Wire - BLUE
e - Charge Indicator Lamp Lead - BROWN
e
a
CAUTION
CHARGING SYSTEM
d
c
b
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