Thread: For all elec guroos

I know wilbur, I thought you was joking, so I did, opps, sorry,

That should be fine. If you have sonar interference, well you will have to home run the ground from the pump and remove the jumper. Grounding sucks.

The Minn Kota us2 has a sneak path to ground if the shield (knurled connector) is grounded. This connector shield is isolated with the Humminbird, but still creates some problems. Again, a lot of the noise is inconsistency in the manufacturers equipment, such as the boat wiring layout itself.

By the way, we should not be calling battery negative as ground as boats do not have a ground. Referring to battery negative as ground with respect to boats is improper nomenclature.

Confusing? ha........I am guilty of this wrong nomenclature.

FYI

Aluminum boats are grounded from the starting battery, but DON"T use it as such.

Originally Posted by wilbur

I was told that is the way to get rid of interference. I think there is schematic of it somewhere on here that CP drew up

Yes it does in most systems, but with the US2 you can create a short by doing it. Here's a quote from a memo MK sent to their ASCs:

"US2 motors have internal bonding/grounding wire
connections to eliminate depth finder interference.
This internal bonding/grounding wire links the
trolling motor negative to depth finder battery
negative (starting battery negative). The
combination of US2 motor internal bonding and the
external ground connections could cause a shorted
condition. This could result in damage to the motor
that would not be covered by Minn Kota’s warranty.
To address these issues caused by improper boat
wiring, we in the process of adding an internal fuse
to the motor bonding/grounding wire."

For the full text, read the post by jonestrollingmotor at BBC Boards: John Jones - Minn Kota US2 Short Problem It's a ways down the thread.

Note that the fuse doesn't allow the system to run with a common ground, rather it protects the transducer from damage.

This is what I measured. Shield (knurled connector) is connected to the TM housing. The path would be thru this sheild if connected via a head unit. The shield is not continuous thru the HB connector. I don't know about the Lowrance. It is an issue. It is a single ended shield, but I believe it has no reference except when the motor is pulsed on (via n channel fet thru control circuit). This is what I am reading with my meter. Haven't scoped it out yet. too cold.

Glad you mentioned this.

Again, my Sonars have their own batteries.

PS I am theorizing from previous observations. Nothing is factual.

I looked at the MK wire drawing. The brown wire going into the TM head is connected to some ground reference in the control module and is probably fused in the motor housing. Sneaky.

Most ground wires are not fused, except maybe Russian stuff and CYA fixes.

So, do not tie the start batteries together as I previously stated until I look into this. This could be a potential problem with Lowrance . I will look at this closely when ever it warms some. Sorry folks. I try hard.

You try too hard CP you better grab a cold one and chill out for a while. In the meantime i will run the neg from the pump directly to the TM battery. Notice I said NEG instead of ground. It takes me a while