TterrovaHhumminbir Interference
I just installed a Terrova 55/US2 on my boat, attached the 597ci-hd-di-combo Humminbird transducer to the trolling motor, gave it a test and had nothing but vertical lines on the display. I tried grounding the trolling motor to the boat ground, and this helped a little, but it was far from a satisfactory solution. I read up on all the other things that could help, taking the motor to a authorized Minn Kota repair shop and having the motor fixed, replacing the standard power cable with a shunted cable, and adding filters to other various parts of the motor controls, but rather than jump in to all that, I tried powering the Humminbird from a separate battery, - - - problem solved; the display was perfectly clear, not a bit of interference anywhere.
I would definitely recommend this as a first step if you experience any interference from a Terrova. It may save you having to do anything else.
B-