So I bought a helix 7 SI this year and notice interference on the helix when I start the trolling motor. They run off the same 12 volt battery but cables are on different sides of the boat. I have a motorguide W55 wireless bow mount trolling motor (12 volt). I borrowed a buddy's battery and had no interference when running them to different batteries. I would prefer to run them to the same battery to save weight as I fish 9.9 limit areas and want to maximize my speed. I am in a basic 14 foot jon boat with no decking. Any ideas? 

 

Also, I saw on another thread you can try using a smaller batter for the finder. I found this one but do I need to be concerned about arcing when charging or using due to how close the terminals are? Or does an arc only occur if metal connects the two. There is a pic below of the battery with a penny for scale. Thanks guys!

You will always get interference when running a trolling motor and fish finder to the same battery. Have to run separate power sources or run to your cranking battery. 

Hook up before plugging in charger.

32 minutes ago, Jig Man said:

Hook up before plugging in charger.

Did this and worked fine. Thanks! Any other tips for interference? I have seen posts where others run off the same battery without issue.

Run a seperate ground wire for the TM mounted TD, the interference is a ground loop from the motor. Insulate the positive batter clip, with a rubber boot or simply electrical tape over the clip handles so they can't short by touching the negative clip.

Tom

4 hours ago, WRB said:

Run a seperate ground wire for the TM mounted TD, the interference is a ground loop from the motor. Insulate the positive batter clip, with a rubber boot or simply electrical tape over the clip handles so they can't short by touching the negative clip.

Tom

Thank you for the help, but can you explain this further? What is the TD? How do I run a ground wire? There is only a black and red wire coming from the TM.

 

Are you saying I should insulate the positive clip so the clip of the TM won't touch the clip from the FF? I don't understand how the positive clip would touch the negative clip? Wait, I think you are talking about my battery charging issue in this part. That now makes sense.

 

Thanks for your help and patience.

2 hours ago, s freud said:

Thank you for the help, but can you explain this further? What is the TD? How do I run a ground wire? There is only a black and red wire coming from the TM.

 

Are you saying I should insulate the positive clip so the clip of the TM won't touch the clip from the FF? I don't understand how the positive clip would touch the negative clip? Wait, I think you are talking about my battery charging issue in this part. That now makes sense.

 

Thanks for your help and patience.

Looking the battery photo closer with a penny for reference the clips handles are insulated and should be OK. TD means transducer, the black wire is your ground and needs to be grounded to the boat hull near the TM. Motor Guide is a metal TM and mounting bolts can be used if the surfaces are metal and not painted. Cranking batteries usually use the outboard motor for a ground, the reason most anglers use that battery to power electronics. 

Tom

 

21 hours ago, WRB said:

TD means transducer, the black wire is your ground and needs to be grounded to the boat hull near the TM. Motor Guide is a metal TM and mounting bolts can be used if the surfaces are metal and not painted. Cranking batteries usually use the outboard motor for a ground, the reason most anglers use that battery to power electronics. 

Tom

 

So if I am following you correctly, I can just attach the black TM wire to one of these bolts on my TM quick release mount and I should be good. Correct? Thanks again for your help. 

On 1/19/2019 at 10:41 PM, WRB said:

Looking the battery photo closer with a penny for reference the clips handles are insulated and should be OK. TD means transducer, the black wire is your ground and needs to be grounded to the boat hull near the TM. Motor Guide is a metal TM and mounting bolts can be used if the surfaces are metal and not painted. Cranking batteries usually use the outboard motor for a ground, the reason most anglers use that battery to power electronics. 

Tom

 

One more question, can I run the ground to the boat if I have an aluminum boat? A thread above made me wonder. Thanks again. 

Yes. You are going to add a jumper wire from the black wire to ground. Aluminum is very conductive and grounds directly to the water.

Tom

 

Thanks again!

 

On 1/19/2019 at 3:14 PM, WRB said:

Run a seperate ground wire for the TM mounted TD, the interference is a ground loop from the motor. Insulate the positive batter clip, with a rubber boot or simply electrical tape over the clip handles so they can't short by touching the negative clip.

Tom

Tried this but it didn't work. Does the boat need to be in the water for a proper ground? I took the negative wire off the battery and attached it to a bolt into the boat. Actually tried two different bolts. No luck. I'm assuming I did something wrong.

3 hours ago, s freud said:

Tried this but it didn't work. Does the boat need to be in the water for a proper ground? I took the negative wire off the battery and attached it to a bolt into the boat. Actually tried two different bolts. No luck. I'm assuming I did something wrong.

Yes, the boat must be grounded by water to have a ground. Your trailer and tires isolate the ground path unless you use the battery negative post, as I recall you are grounding to the boat.

Tom

I know this is old but rather than moving the ground wire from the negative post to the boat.  I think you should leave the ground wire on the negative battery post and run another wire from the negative battery post to the boat.  This should ground the boat, then run a wire from the quick release bracket to the boat.  Or run a separate wire from the negative post to the quick release bracket.  I think this would eliminate the trollers ground loop interference without requiring the boat to be in the water...once again, I think, I’m not sure.

 

I’d like to hear if you solved this, as I’m attempting to tackle the same thing on a large (blue sky 360) kayak.