You need to wire the graphs independently to the cranking batteries, ground cranking battery to last trolling motor battery, and lastly do not run your transducer cable down the trolling motor head power wire that goes to your foot pedal, instead run it down the frame of the trolling motor mount that mounts to your boat. I think if you run your power to the cranking battery you should solve the issue. Also make sure the fuse in the head of the trolling motor is intact, and ground your trolling motor. Try these suggestions should work, it did work for me and my birds. I still get erratic depth readings for some reason in 8ft or less of water for some reason, trying to figure this one out still!