Never seen this before...battery help

[Koma]

Sorry for the long post but here's what I have...

A buddy is having some issues with interference on a graph at the bow of his boat whenever he hits the button on the trolling motor. I switch the transducer to the GT 56 on the jack plate and there is no interference when you hit the TM button. So I start checking things out and find that he has a run and gun charger that basically ties into his dedicated 16V graph battery. So I guess that may be his problem and unhook everything off the graph battery and perko switch. This didn't fix the interference.


He just had a power pole move put on his boat and didn't have the issue with his Force TM, so I'm thinking it had something to do with how they wired up the display panel and foot pedal. I check and they are wired to a blue seas fuse block and those are the only things wired to the fuse block. So I chase the wire that is feeding the fuse block and it is a dedicated set of wires that are run to the cranking battery but there is a negative wire that ran from the cranking battery to the dedicated graph battery. I remove it and still have the interference. At this point the only thing wired to the graph battery is the sea clear harness. All the graphs and live scope fire up and work fine but still have interference.

The run and gun charger had a positive wire on the #2 side that went to the cranking battery. I put the test light on and the other end hooked to the negative terminal. I couldn't get it to light up. I hit the test light to the positive side of the graph battery and it lights up, keep in mind the negative is hooked to the cranking battery! I completely unhooked everything off both batteries run each wire down to know what they're for and put it all back together. I couldn't get it to light up< I again touch the graph battery and it lights up. I unhook the sea clear negative wires off the graph battery and test it and it won't light up. I touch the sea clear negatives to the terminal and it lights up.

I stumped so I start testing everything and I have one end on the positive on the cranking battery and the test light on the positive of the graph battery and the test light lights up but very very dim. Now I'm really confused! What in the world would make this happen? About the only thing I can think of is there is a bad ground somewhere in the sea clear harness?

I put the back end of the boat back together and am gonna go back tomorrow and unhook all the graphs and live scope off the sea clear harness and redo everything and see if something there is messed up? I don't know what else to do or what would cause this so I figured I'd check here and see if anyone has any idea's? Any help would be greatly appreciated

[MichAngler]

Couple of things I can think of

There should be ground wires connected to the GLS10 black box and the back of the Garmin graph see if they are connected to the cranking battery or dedicated battery

Run a voltmeter from the trolling motor to the Jackplate see if you have voltage – find a bare metal connection on the trolling motor if you have voltage the jump switch is incorrectly installed

[Koma]

Update...I tore everything apart and basically rewired everything. What I found was when I put power to the NMEA backbone I was getting the power feedback to the graph battery. I unhooked it and ran a drop outside the boat to test it and it was all good. My buddy had to have a new powerhead put on over the winter so I'd say that when that was done the cable was compromised somehow. Good news is it's fixed, bad news is he still has the interference when we hit the trolling motor button so we're still chasing that issue. I just thought I'd pass the info along in case someone else every has something like this happen to them

[lpugh]

What trolling motor is on this boat?

[Koma]

What trolling motor is on this boat?

Power Pole Move....Had a Garmin Force prior to this and didn't have any issues but to be fair, he's added some other things along with the power head replacement so I'm not ready to say it's all due to the new move trolling motor. I have the same graphs and the Move on my boat and I don't have any interference on mine. He does have a transducer shield saver with a GT36 on his trolling motor and I don't

[NoCAL]

I always had interference on both 2D and Downscan with a brushed Fortrex. Changed out to a brushless Ghost and never seen another issue. But the Move is brushless isn’t it? IMO, it’s got to be related to the motor itself and not all the other wiring.

NoCAL

[lpugh]

Supicious of a ground connection between cranking and TM batteries, could very well be the charger

[Koma]

I always had interference on both 2D and Downscan with a brushed Fortrex. Changed out to a brushless Ghost and never seen another issue. But the Move is brushless isn’t it? IMO, it’s got to be related to the motor itself and not all the other wiring.

NoCAL

Yes sir it is brushless. It may not like the external transducer on it

[Koma]

Supicious of a ground connection between cranking and TM batteries, could very well be the charger

I thought that as well. I have everything unhooked from both batteries except the graphs on the 16v and the troller on the 36v and it's still there.
I'm gonna pull the transducer off his boat tonight and put it on mine and see if i have the interference with it on