I have just gotten my first Fishfinder/Plotter (Lowrance Elite 5 HDI), that I am putting on my open construction 16' Skiff that is powered by a 20 HP 4 Stroke Yamaha. I am running a Transducer off the stern and am going to mount the Fishfinder unit just forward to my rear bench seat. I am looking at two power options: 1) I have a smaller cranking battery (BassPro Power Series AMG Deep Cycle 48 - with approx. 200 Cranking Amps) in the stern, but I have been cautioned by some that this should be a "dedicated" cranking battery, since it is on the smaller size. 2) I have a large Deep Cycle Trolling motor battery in my bow compartment that others have said that is the way to go. I will have to run an extension wire probably 10-12' back to the Unit but that is not a huge problem. I have read a little that one should not run a trolling motor and a Fishfinder off of the same battery as there will be possible "interference" on the Unit from the Trolling Motor. I'm not "electrical" and want to do this correctly. Are there members of the Forum that could help with some advise? Thanks so much!!!