I just purchased a Helix 5 sonar for the bow of my Lund. Looked up front and found a set of unused electrical connections but when I checked the voltage I found 24 volts. Tried looking on line for a wiring diagram but didn't find anything specific to the Lund 1775 Impact. Is there another point I can connect up front or would it be better to snake a wire back to the starting battery? Don't like the idea of a power wire just sitting in the bottom of the hull where it could corrode over time. The Terrova is 24 volt. Can I connect the 12V power to the helix to just one of the trolling motor batteries? Thanks for any input or advice!