Electrically sound

[JohnK]

I've been plagued with noise on my new graphs. It became manageable when I ran a bond wire front tm skeg to the negative if the starting battery, where my graph power comes from. The starting battery neg. is connected to the tin hull thru the big motor while the tm is not. However the tm negative is connected to the skeg so now they're all common. I'm thinking anyway. Is this a sound electrical practice. Will it hurt the hull, like pin holes? Anybody been doing this for a while?

 

[Bailey Boat]

Use a dedicated power source for the electronics as recommended by the manufacturer and I'll bet your issues go away....

 

[JohnK]

Use a dedicated power source for the electronics as recommended by the manufacturer and I'll bet your issues go away....

If I move the transducer a foot away from the motor all is good. I'm thinking that must be the source. It's also the battery charger but I took that off. I guess I'll try the after market tm harness from minn kota. Minn Kota says to connect negatives from the tm and starting battery together?

 

[user 26281]

I've been plagued with noise on my new graphs.

Did you graphs come with ferrite chokes and did you install them?

 

[thill]

You can buy Ferrites on Amazon or Ebay for not very much. They make a big difference.

Some trolling motors do that. I had one that was bad. Sold it with a boat at my first opportunity. Someone here could probably tell you what was wrong inside the motor. None of my newer motors have ever caused interference.

Yes, you can tie all your grounds together, as is standard on a lot of boats. I've done it, depending on the boat. I typically don't in my jon boat, as the TM batteries are way up front and I don't have any interference issues.

 

[MDCrappie]

I've been plagued with noise on my new graphs. It became manageable when I ran a bond wire front tm skeg to the negative if the starting battery, where my graph power comes from. The starting battery neg. is connected to the tin hull thru the big motor while the tm is not. However the tm negative is connected to the skeg so now they're all common. I'm thinking anyway. Is this a sound electrical practice. Will it hurt the hull, like pin holes? Anybody been doing this for a while?

It's know as "bonding" and (IMHO) it should be done. Here is pretty good explanation write up from 20 years ago.
I've done this with all of my (many) aluminum boats over the years.
https://www.walleyecentral.com/forums/showpost.php?p=662879&postcount=21

 

[Still Afloat]

I've been plagued with noise on my new graphs. It became manageable when I ran a bond wire front tm skeg to the negative if the starting battery, where my graph power comes from. The starting battery neg. is connected to the tin hull thru the big motor while the tm is not. However the tm negative is connected to the skeg so now they're all common. I'm thinking anyway. Is this a sound electrical practice. Will it hurt the hull, like pin holes? Anybody been doing this for a while?

Try connecting the TM bonding wire to the hull. Running a separate bonding wire could create a ground loop if your boat is aluminum. I’d also check for poor power connections to and in the TM.

I agree that a different power source for electronics is a best practice. Either a house battery or the starter battery, if your motor isn’t too big to pull start. For bigger motors a marine deep cycle lead acid house battery can back-up the starter battery. Install an A/B battery switch (house/starter) or have a set of jumper cables on the boat.

It’s always best to use clean power or eliminate the noise. Chokes can be effective but, they are more of a patch than a fix.

 

[KevinWI]

Recently, and I'm not even sure when it happened, I developed interference on my Humminbird SI screen. 3 vertical lines on the starboard side (same side transducer is mounted).
I never got it solved before the season ended. I don't use SI very much as I'm still trying to learn what I'm seeing....so I didn't notice when it happened....I made so many changes on my boat lately, all that involved electronics, it's going to take a miracle to track down.....
Main changes have to do with installing and running network cables alongside transducer and power cables. I was just cleaning up my cabling. I also recently installed bus bars to clean up too many connections on a single battery terminal.
Interference can literally come from anywhere. Trial and error is really the only way. This spring will not get any better as I'm adding another Humminbird so that will just add more network cabling and more power cabling. It's really going to get difficult.

 

[Still Afloat]

Disconnect everything except the FF and reconnect them one at a time until the noise comes back. Just turning everything off rather than disconnecting may not have the same effect but, it’s an easy first pass.