Problems with newly installed Garmin 93SV on Trolling Motor- vibration or interferenc

[KevinH-BCB]

I recently purchased a brand Bass Cat Boat and motor. It has the Motor Guide Digital 75 Lbs thrust trolling motor. The rig came with a Hummingbird 788ci HD. I removed the HB and replaced it with a Garmin 93SV yesterday. I tied the new Garmin using the same power source as the Hummingbird (main motor battery). I tried it out today. When I activate the trolling motor, I loose my view in traditional sonar. The side view and downVU (Chirp) seems to be fine when in split screen. When the trolling motor is setting 1 = fine. When is setting 8 it is fine. Its everything in between, you cannot make anything out on the traditional sonar. I tried to upload pictures, but it keeps giving me an error.
Any help would be appreciated!
Thanks!
Kevin

[KevinH-BCB]

I get error 406 when I try to upload the pictures

[Larry3215]

Hi Kevin,

There are a number of possible solutions - which may or may not work. I will PM you my email addy. If you send me the pics I will try to up-load them or convert them so they can be up-loaded. Seeing the pics will help.

Unfortunately there are several different ways interference can be generated and transferred to your sonar.

First a few questions.

Is the 93 transducer mounted to the trolling motor? If so - are you running the cables for the trolling motor and transducer close together at any point? You're easiest fix is to keep the cables as far apart as possible and never run them side by side or tie them together with zip ties etc.

Is there ANY common electrical connection between the trolling motor batteries and the starting battery? Common ground, on-board charger connections, etc.

Answer those questions and send me those pics if you want and I will post them.

[KevinH-BCB]

Thanks for the help - Larry
The transducer is mounted to the trolling motor. The power for the Garmin unit is from the main battery, not the trolling motor batteries. The transducer wire is connected to the trolling motor shaft and along the control / pwr cables, typical with all trolling motor installations. I have soldered the connections and have shrink wrapped them. The old connections to the Hummingbird unit were the same locations and set-up the same. I will check for common ground between the trolling motor batteries and the main starter battery tmr - weather permitting. I do have an on board charger. I'll check to see if it is common to all batteries, but I doubt it. It should be for the trolling batteries only, though I'll check for common ground.
I have run a ground wire from the transducer clamp to ground this morning. The issue is no quite so bad, but still is far from acceptable. I sent a video to you - Larry from today. Hopefully you'll have better luck posted the pictures and video that I have. If you are successful posting pictures and video,please let me know what you did for my future reference.
Thanks again for all of the help!
Kevin

[Larry3215]

Got the pics but not the video.

The easiest first thing to try is separate the cables as much as possible. Thats the most common source of interference.

On the grounding/common wiring - sometimes having the two batteries bonded with a common ground fixes things and sometimes it makes it worse. Sometimes a poor connection on the common ground is the problem. What ever you have now, check all the connections and clean them. If that doesnt work, try disconnecting the common grounds, connections from chargers, etc as a test.

This is some bad interference.

IMG_2932.jpgIMG_2931.jpg

[Larry3215]

Did grounding the clamp help at all? If so, you may need to do some grounding inside the motor controller or the motor itself.

[KevinH-BCB]

No - not really. It did help some, but little. Now with the extra ground to the transducer I get what you see on the right hand pic for about a second, and then did goes to looking like the left had screen. It's fine below a setting of 2 and greater that 8, or your in less than 8 feet of water - strange!

[Larry3215]

That sounds like noise from the motor speed controller. The speed controller pulses power to the motor to control its speed. Slower pulses - further apart - for slower speed, faster pulses closer together - for faster speed. At full speed the power has no pulses at all.

Unfortunately, there are several ways it can get to the sounder. Like I said, the most common is conduction from the power leads to the transducer leads when they are close together. It can also travel through any common connections between the batteries or through the hull or even the water.

Like I said, grounding is often the problem. On some of the Minkota motors, it was necessary to add an internal ground from the control head down to the motor housing. Some guys ran the wire externally and some had Minkota run in internally. Also unfortunately, that isnt always the problem.

You might try calling Motorguide and see if they have any suggestions. I would also call Garmin and see if they have any experience/suggestions with that brand. A Google search for "MotorGuide interference" might turn up some similar reports and maybe some solutions.

Again, what works for one installation may or may not work for another one, but it will give you things to try.

First though, separate those cables.

[TeeDee]

I would support the separating of cables as much as possible theory. Also don't let the ducer cable (if coiled up in the front compartment) get on any power cables period. Next thing that I am doing to mine is to separate the ducer cable from the TM shaft a bit. I hope to accomplish this with some tubing or grommet/gasket material. Also thought about velcro wraps for ducer cable, first wrapping the shaft thne adding the cable. This would get about 1/8" separation and may work. Digital variable speed TM's are much worse than fixed speed ones, as mentioned @ the speed controller. Maxed out you may not even see interference if this is the source. Actually fixed speed units may never see this particular problem.

Also, my particular problem seems to be depth sensitive. Try it in very shallow water, as well as deep and observe the transition depths and performance.

[KevinH-BCB]

Just a short update - I did ohmn out between the negative terminal on the starter battery to the negative on the trolling motors. They do NOT share a ground, so I'm good there. I did not think they would, but is was worth checking, as suggested.
I will do a search on the net regarding Motorguide interference issues.

Larry, TeeDee - When you suggest separate the cables, are you suggesting that I wrap the transducer cable along the trolling motor shaft and pwr cables with something? I've always run the transducer cable along the trolling motor and cabling, to facilitate deployment of the trolling motor. Are you suggesting wrap with electrical tape, spiral wrap, or something like that? I'm not sure of what you are suggesting. Pictures would help alot! Thanks!
Kevin

[Larry3215]

For the initial testing, when I say separate, the important this is physical distance. They should be kept physically as far apart as possible. Inches are better than milimeters and feet are better than inches. Try not to let them touch at any point at all, but better yet have a LOT of distance between them.

The problem is, the power leads on the trolling motor will generate a magnetic field when the speed controller is doing its PWM thing. That magnetic field will induce or transfer the signal to the transducer cable. The closer together they are the stronger the transference will be and the worse the interference will be.

[TeeDee]

Well, I can't do pictures. Really need to learn about that. The utmost thing for me is that the two cables be separated as much as possible. I keep them apart once the ducer cable comes up the shaft to the head. I do not let them be together after that point at all. Because of the variable speed feature sometimes that can introduce interference thru the shaft. I am going to distance my ducer cable from the TM shaft by one of two or three methods. Plastic tubing, or rubber material at the points of tie down or getting my tie-downs to stand away from the shaft. I think about 1/8" will make a difference. I will also, if need be, try to pad between motor head and duceer cable. I will try to do this soon to see what works--if any. Will report back

[KevinH-BCB]

Just an update - Friday, I did the following:
- Ran a ground wire from the negative on the trolling batteries to the starter battery ground buss. Verified that there was a shared ground between the battery sources. Still have the interference.
- separated the transducer from the trolling motor - still interference
- attached ferritte magnets to both ends of the transducer cable, pwr cable to the fish finder, and to the pwr wire on the backside of the trolling motor plug - still interference.
- I removed the trolling motor and took it to an authorized repair shop and had them install an internal ground from the ground wire inside the head to the metal head casing. - No interference.
- I then removed the shared ground wire - still good. Mounted transducer = still good, finished up the installation - I got a spike of interference when I activated the trolling motor. With some experiments, I believe that it was caused by the transducer excess wire being crossed on itself inside the boat. I removed the Transducer wire and coated it with aluminum tape (what a pain). I then taped it up with electrical tape to cover& protect the transducer shielding. I them put spiral wrap on it to protect it and hold it away from the trolling motor and cabling. Hopefully this will correct the issue. I'll have to wait for the weather to cooperate before I can test it on a local lake.

[C Parker]

Glad to see someone fix the interference issue! It gives me hope...

Will you update us on weather or not your homemade shielding works?

Thanks

[Larry3215]

Lwinchester posted a link in another thread (post 7) that sums up the issues and possible solutions very well.

http://www.bbcboards.net/showthread....12#post8057712

[ncbass]

Hey Kevin, any update on this??

[KevinH-BCB]

Update - It is much better. I get a spike when the trolling motor is activated and there is some noise, but readable. Not sure what to do at this point. I am considering swapping out this unit with another. This one is a DownVu version. I also have a ClearVu version, which is the new one. The only thing left to do is to run new power & ground on the opposite side of the boat away from everything else, which. Would be a pain - to say the least.

[catmantwo]

Kevin, since you are running a BCB take a look at their power cable for graphs in their online store.
Solves a lot of power problems, not too difficult to install.

http://www.basscatstore.com/powercableforgraphs.aspx

[Scoand70]

I recently purchased a brand Bass Cat Boat and motor. It has the Motor Guide Digital 75 Lbs thrust trolling motor. The rig came with a Hummingbird 788ci HD. I removed the HB and replaced it with a Garmin 93SV yesterday. I tied the new Garmin using the same power source as the Hummingbird (main motor battery). I tried it out today. When I activate the trolling motor, I loose my view in traditional sonar. The side view and downVU (Chirp) seems to be fine when in split screen. When the trolling motor is setting 1 = fine. When is setting 8 it is fine. Its everything in between, you cannot make anything out on the traditional sonar. I tried to upload pictures, but it keeps giving me an error.
Any help would be appreciated!
Thanks!
Kevin

I have a BCB with a Minn Kota Fortrex and Garmin 93SV. I had horrible interference. I ran a ground wire to the Transducer bracket attach bolt directly to the grounding bus bar that I installed for my electronics which I installed under my console. The bus bar is direct power and ground to my starting battery. Zero interference. In also have my transducer wiring completely separated from any power wires.

[oli3665]

Sco, so did the BCB do anything for combating interference? I don't have one and I have a minn Kota maxxum and really want the 93 up front w/ the ducer going on the T/M. Also my trolling motor is one in which there is a click at each number.