Mercury Freshwater Manual page 18

Sensitive electronics, depth finders in particular, should be connected
directly to the main engine battery. If only a one battery system is
used, then connect with separate cables.
ESTABLISHING A COMMON GROUND
MotorGuide recommends isolating the trolling motor battery/batteries
from the main engine battery.
Electrolysis issues: Using the engine starting battery as a source of
power for any trolling motor may cause electrolysis on metallic parts.
• If you have followed the battery wiring and installation
instructions in this manual and your boat continues to have
electrolysis issues, you will need to separate the trolling motor
from any other boat electronics.
• Remove the engine starting battery from the wiring configuration
of the boat and isolate the power circuit for your trolling motor.
Establish a common ground: Common ground means the ground
for the main engine accessories and your trolling motor are
connected to the same negative ground terminal.
• Not having a common ground can cause severe corrosion or
electrolysis. If left unchecked, damage may be caused to your
trolling motor and boat.
• Establishing a common ground connection will allow increased
sensitivity and improve detail on a sonar display.
RECOMMENDATIONS
Battery type: The recommended battery is a 12 volt deep cycle
battery.
Circuit protection: MotorGuide recommends installing a 50 amp
manual reset circuit breaker in line with the trolling motor positive
leads within 180 cm (72 in.) of the batteries. To order a circuit breaker
kit, contact your local service dealer, request kit number MM5870.
Wire size: For optimum performance, MotorGuide recommends the
use of 13 mm (6 gauge) wire if extending the existing wire beyond the
standard battery cable supplied with the product.
WIRING AND BATTERY
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