Originally Posted by Don In Denver
They are already on separate electrical systems.
So the trolling motor has a separate set of batteries. Did you make a common ground?
My motorguide manual says this:
Establish a 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
Hope this helps.