Trolling motor and fishfinder

So I figure I have to ask a question about both, together, in order to be able to post here .<br /><br />Trouble is, I do have such a question.<br /><br />I have a Motorguide 46lb, 12v electric and a Eagle Fishfinder 240 with a portable unit. I am unable to use them together as when I turn the motor on, I get lines all over the finder. This did not happen when I had a cheaper MinnKota 30 lb electric and seems to be due to the variable speed on my new motor (the reason I bought it). I can revert the finders portable box back to D cells (which means buyin D cells) or I can carry a second battery for the finder and switch around when one dies, but I'd like some sort of isolator for the setup.<br /><br />Anyone have any idea how to hook both to the same battery without interference?

Re: Trolling motor and fishfinder

Howdy, TW.<br /><br />Do you have each connected directly (through its own fuse or circuitbreaker) to the battery terminals? If not, try that.<br /><br />Good luck.

Re: Trolling motor and fishfinder

Yes. This is in my 12' cartopper (trucktopper???).<br /><br />I drop the battery in the back of the boat and hook stuff up. No extra wires, switches or anything.

Re: Trolling motor and fishfinder

I've heard of other people having problems like this but I can't remember how they fixed it. If you have a Radio Shack or other type of electronics store near you ask them if a noise suppressor might help.

Re: Trolling motor and fishfinder

Perhaps a capacitor across the leads of the fishfinder? This is basically what a noise suppressor does. The capacitor will act as a shock absorber, soaking up voltage spikes created by the motor, then emitting them during a lull. Smoothing out the signal. No idea if it would really work or not but I would try putting no specific one in paralell just to see if it helps.<br />my .02<br />Craig

Re: Trolling motor and fishfinder

TW, did you catch that part about each in JB's post? if you have 1 wire feeding both at some point in the cabling, it would probably help to separate them.

Re: Trolling motor and fishfinder

Tackelwasher<br />Make sure each has it own 12 volt and ground wire all the way to battery. On the Trolling motor place some ferite beads on both wires near the trolling motor. Do not run the wires for the trolling motor and the wires for the depth finder side by side all the way back to battery. If your have two batteries run just the trolling motor on the deep cycle. <br />On the Depthfinder install a Noise filter near the unit. Also oK to install ferite beads on power cable to depth finder. Last thing is make sure the transducer cable not running next to the trolling motor power cable. <br /><br />The ferite beads will remove RF (radio frequency) interference from power cable. For the trolling motor going to need a big bead to be able to wrap wire around it. On the depth finder the ferite beads will help in two ways one to stop trolling motor interference from getting to depth finder and the other to stop the depth finder interference from getting to your VHF radio. The best noise filter are a LC filter (Coil choke and a Capacitor) and work quite well.<br />Radio Shack did carry both the ferite beads and the LC niose filters. West Marine also did carry the LC noise filters in the past. I have not had to buy one is some time so not sure if either carries them now.

Re: Trolling motor and fishfinder

You should be able to get an inline noise suppressor from Radio Shack. They use them on some car stereo installs to eliminate noise.