Joel, me too, I think I will go back to the external puck……after this trolling motor. Or take it apart and wrap foil around the whole sonar cable and puck to try and sheld it better from the motor in the lower unit. I am happy with the motor just frustrated with the US/US2 as minnkota said it wasn’t their issue.

I posted this under the other US issue but I will post it here.

When I was talking to Vexilar it seem that it is a shelding issue with the US cable by the motor. I think it needs some extra shelding as the issue your seeing is radiated noise.

Please read below as the issue would be with any locater you use with your minn kota.

There are two possible sources of the interference. One is conducted interference, caused by the Pulse Width Modulation speed control in the motor sending pulses into the power circuitry. The other is radiated interference, electromagnetic interference (EMI) from the motor’s lower unit and brush leads. Before you can solve the problem, you’ll need to determine the source of the interference. Here’s how to tell, unplug the transducer from the back of the depth finder. Now run the motor. If you no longer see interference, the problem is radiated noise. If you do, the source is conducted interference from the power line.

To solve conducted interference, you’ll need to connect the main negative trolling motor battery post (where the negative trolling motor power wire connects) to an effective earth ground. This can be the negative post on your cranking battery or the hull of the boat, if it’s an aluminum hull. Use a small wire, 18 gauge wire will do, with a 1 amp fuse. If you have an on-board charging system, you need to be careful. If the trolling motor power wires connect to the charger, and do not connect directly to the batteries, you’ll need to contact the charger manufacturer for further instructions.

If the source of your interference turns out to be radiated noise, you’ll need to add a Ferrite Core, a simple piece that attaches to the transducer wire, or replace your transducer, or possibly both. We have been experiencing this issue mostly with the high-thrust motors. The 36 volt motors are the worst. Last year we developed a new Puck that greatly reduces this noise. A new style transducer along with the Ferrite Core should completely eliminate the noise, even in severe cases.

—–

Minn Kota / Vexilar Interference Solutions

Our testing regarding interference from the Minn Kota motors on our FL-8 and FL-18 depth sounders have found some ways to help eliminate the problem of electromagnetic interference being displayed.

Common Ground – Some boats have a common ground where the negative of the trolling motor battery is connected to the negative of the starting battery. Although this wire has been helpful in the past to eliminate conducted interference from the trolling motor speed control (Pulse Width Modulation) circuitry, we have found that this connection introduces EMI noise into the rest of the boats electrical system. Removing this connection can significantly reduce the interference.

Cable Locations – Making sure that any and all power and transducer cables are as far away from the trolling motor power cables will help reduce interference. Simply neatening up wiring jumbles into neat bundles, separated between deep-cycle and cranking battery sources will help.

Universal Sonar Grounding – The Vexilar trolling motor transducers have a small metal tab that protrudes from the top of the puck. This ensures a good shield ground at the point of the interference, which significantly reduces noise on the display. The Minn Kota U.S. system does not have this ground. The motors transducer cable is shielded, and this shield is only connected through the depth sounder to the cranking battery negative. However, the final ground to earth (the water) is far away from the motor, usually ending at the outboard. Connecting the transducer shield inside the lower unit to the metal motor housing would be the best way to get a good ground, but achieving this after the motor is built is difficult. For aluminum hulls, connecting the negative of the cranking battery to the hull and then connecting the bow mounted depth sounders negative to the hull in front should help interference problems. This is similar to automotive systems where the chassis is the ground current path. For fiberglass hulls, the easiest solution may be simply to use an external transducer that has the ground tab. Another, more invasive, solution may be to tap into the shield within the U.S. adaptor and connect this to a ground point as close to the motor as possible.

Defective Parts – The transducer cable shield is extremely important to clear sonar reading in all marine situations. If the shield is not continuous, the “drain path” for the interference is not complete. Defective transducer cables and adaptors, as well as bad connections within connectors and jacks can cause problems. A simple continuity check to ensure a complete circuit from the earth ground point (outboard lower unit or aluminum boat hull) to the grounding tab on the transducer will tell if there is a problem. For Universal Sonar systems, check from earth ground point to the end of the adaptor plug that connects to the motors transducer cable. Further checking would require a service center visit.

Ferrite Core – A ferrite core is a part that attached to the exterior of a cable that has interference noise within. We found that ferrite cores had little effect on severe interference from the Minn Kota motors. However, mild noise (green color with some orange) was controllable with this solution.

Oh I also forgot to mention. My issue was with Radiated noise. Could be caused by the US cable not being shelded enough by the motor. So when you have a 24v or 36v, your going to have some issues.

What fixed my issue was this. Snapped it on the US cable and it cleaned up the noise.

http://www.radioshack.com/product/index.jsp?productId=3012599

1. You have to have the adapter for your vex to work and I assume you do.

2. What voltage is your motor reason why I ask, see below.

3. Test out the power cables on your vex, plug them into your battery pack that you use for ice fishing to take out your deep cycle or starting battery from the loop. Not good to share the same battery as your trolling motor.

4. Read below as I bet your having some interference. Let me know if I can help you out with something, as I spent about the better part of last fall and this sping messing around with my US2 and my vex.

There are two possible sources of the interference. One is conducted interference, caused by the Pulse Width Modulation speed control in the motor sending pulses into the power circuitry. The other is radiated interference, electromagnetic interference (EMI) from the motor’s lower unit and brush leads. Before you can solve the problem, you’ll need to determine the source of the interference. Here’s how to tell, unplug the transducer from the back of the depth finder. Now run the motor. If you no longer see interference, the problem is radiated noise. If you do, the source is conducted interference from the power line.

To solve conducted interference, you’ll need to connect the main negative trolling motor battery post (where the negative trolling motor power wire connects) to an effective earth ground. This can be the negative post on your cranking battery or the hull of the boat, if it’s an aluminum hull. Use a small wire, 18 gauge wire will do, with a 1 amp fuse. If you have an on-board charging system, you need to be careful. If the trolling motor power wires connect to the charger, and do not connect directly to the batteries, you’ll need to contact the charger manufacturer for further instructions.

If the source of your interference turns out to be radiated noise, you’ll need to add a Ferrite Core, a simple piece that attaches to the transducer wire, or replace your transducer, or possibly both. We have been experiencing this issue mostly with the high-thrust motors. The 36 volt motors are the worst. Last year we developed a new Puck that greatly reduces this noise. A new style transducer along with the Ferrite Core should completely eliminate the noise, even in severe cases.

—–

Minn Kota / Vexilar Interference Solutions

Our testing regarding interference from the Minn Kota motors on our FL-8 and FL-18 depth sounders have found some ways to help eliminate the problem of electromagnetic interference being displayed.

Common Ground – Some boats have a common ground where the negative of the trolling motor battery is connected to the negative of the starting battery. Although this wire has been helpful in the past to eliminate conducted interference from the trolling motor speed control (Pulse Width Modulation) circuitry, we have found that this connection introduces EMI noise into the rest of the boats electrical system. Removing this connection can significantly reduce the interference.

Cable Locations – Making sure that any and all power and transducer cables are as far away from the trolling motor power cables will help reduce interference. Simply neatening up wiring jumbles into neat bundles, separated between deep-cycle and cranking battery sources will help.

Universal Sonar Grounding – The Vexilar trolling motor transducers have a small metal tab that protrudes from the top of the puck. This ensures a good shield ground at the point of the interference, which significantly reduces noise on the display. The Minn Kota U.S. system does not have this ground. The motors transducer cable is shielded, and this shield is only connected through the depth sounder to the cranking battery negative. However, the final ground to earth (the water) is far away from the motor, usually ending at the outboard. Connecting the transducer shield inside the lower unit to the metal motor housing would be the best way to get a good ground, but achieving this after the motor is built is difficult. For aluminum hulls, connecting the negative of the cranking battery to the hull and then connecting the bow mounted depth sounders negative to the hull in front should help interference problems. This is similar to automotive systems where the chassis is the ground current path. For fiberglass hulls, the easiest solution may be simply to use an external transducer that has the ground tab. Another, more invasive, solution may be to tap into the shield within the U.S. adaptor and connect this to a ground point as close to the motor as possible.

Defective Parts – The transducer cable shield is extremely important to clear sonar reading in all marine situations. If the shield is not continuous, the “drain path” for the interference is not complete. Defective transducer cables and adaptors, as well as bad connections within connectors and jacks can cause problems. A simple continuity check to ensure a complete circuit from the earth ground point (outboard lower unit or aluminum boat hull) to the grounding tab on the transducer will tell if there is a problem. For Universal Sonar systems, check from earth ground point to the end of the adaptor plug that connects to the motors transducer cable. Further checking would require a service center visit.

Ferrite Core – A ferrite core is a part that attached to the exterior of a cable that has interference noise within. We found that ferrite cores had little effect on severe interference from the Minn Kota motors. However, mild noise (green color with some orange) was controllable with this solution.

Call them today and they directed me to take it to a service center. They called minnkota after the information I gave them. He told me that minnkota said it would be an issue with my Vex.

If anyone lives near waconia and wouldn’t mind me borrowing their FL8SLT or FL18 that would be great.

I have never had any issues with them. I like making the trip down there cause you never know what they have on hand which is sometimes good and bad. I would call down there if your looking for something specific to make sure they have some on hand.

I never had to worry about breather ports on my cover.

I have 17 footer, full windshield, trolling motor and it also goes over the outboard.

I think mine cost about $480 from CC. Stand up people there and stand by their product. It also comes with bungee straps, they even gave us a couple extra. Fits like a glove 3 years later.