Ulterra blown internal ground wire fuse

[suvowner]

so I have a 2 year old ulterra that recently started to show a ton of rfi on side imaging, that I never had the first 2 years, I have isolated it to the bps xps 3 bank charger, replaced the charger and same behavior, so replaced with a minkotta precision and no more extreme noise from the charger, but still a little bit at 800khz on max sensitivity. and another source of noise is the metal barrel of the us2 cable, if it touches my network able from my bow to console unit i get a lot of noise.

my question is:
what could have caused the tm internal fuse to blow, min kotta says a short within the motor, is there another likely cause ?
I have an extended warranty that covers my tm, should I push to have it replaced, or is this amount of noise considered acceptable ??

I did open the lower unit and confirmed no water intrusion, but dont know how to go deeper inside the lower unit so tightened it back up.

[CatFan]

Some way or another you have a connection between the TM batteries and the battery that runs the electronics.

[suvowner]

Some way or another you have a connection between the TM batteries and the battery that runs the electronics.

ok, how can you tell if the trolling motor itself is making excessive/abnormal amount of rfi or not ?

is it normal to pick up much noise off of the us2 cable ??

[CatFan]

ok, how can you tell if the trolling motor itself is making excessive/abnormal amount of rfi or not ?

is it normal to pick up much noise off of the us2 cable ??

Trolling motors make a ridiculous amount of electrical noise. So much that it would be difficult to get them to make more noise if you wanted to.

Find the connection between batteries and replace the fuse.

[suvowner]

Trolling motors make a ridiculous amount of electrical noise. So much that it would be difficult to get them to make more noise if you wanted to.

Find the connection between batteries and replace the fuse.

ok, well replacing the fuse and switching from bps xps 3 bank charger to min kotta precision charger has reduced 90% of it......still dont understand why the bps xps charger didn't cause the rfi the first 2 years ? now just looking for a way to get rid of that last 10% of noise if possible.....have some ferrite chokes on the way, plan to put on power cable of both units and i-pilot link cable and us2 cable to start with.

[Bradrodfish]

Was the power to the Troll motor turned off while you were charging your batteries? If not the bad charger could have caused the problem. If you are still getting RF on the graphs then you could have an issue with the troll motor. As said above you may also have a problem with a connection between the Boat battery and the troll motor batteries.

[suvowner]

This was an interesting read.


Conducted Interference

If you disconnect your transducer from your depth finder and you continue to see noise when the trolling motor is running, then you are dealing with conducted interference coming in through the power connection. This can happen when the boat's electrical system does not have one common ground that connects to the water. Using a multi-meter, available at places like Radio Shack, check for proper grounding in your boat's electrical system. Set the meter to measure resistance or continuity. Then connect one lead to the negative battery post that connects to the trolling motor and the other lead to the negative post on your starting battery. The reading should show zero and the meter may beep. Also, check between the negative starting battery post and an unpainted portion of the outboard motor, like the prop shaft or trim tab. You should also measure a complete circuit here as well. If the ground connection is missing between the trolling motor battery and the starting battery, add a small gauge wire, about 18 AWG, with a 1 amp fuse. This will complete the ground connection here. If the ground to the outboard motor is missing you should take your boat into a service shop to see why the ground is missing. All outboards should have this ground. If yours is missing something is wrong. If all grounds are in place, but noise is still a problem, a Ferrite Core can solve the problem.Electromagnetic Interference

While you’re electric trolling motor is running, disconnect your transducer from the back of your unit. If the interference goes away, then you have EMI created by the rapidly switching voltage and powerful DC motor in the trolling motor's lower unit. Proper grounding and Ferrite Cores can be a good remedy for this type of interference. First, be sure your system is grounded

[CatFan]

If the ground connection is missing between the trolling motor battery and the starting battery, add a small gauge wire, about 18 AWG, with a 1 amp fuse.

Don’t do this ever on a motor with internal sonar. It will blow the fuse and disable the noise reduction circuit.

I wouldn’t add a ground to the hull either.

[suvowner]

ok good tips thanks........using a meter to prove or disprove a path to the starting battery seems like it would be helpful ?

[CatFan]

ok good tips thanks........using a meter to prove or disprove a path to the starting battery seems like it would be helpful ?

No good reason to do it. It won’t measure zero anyway, and glass boats have no hull to connect to. If grounding the hull made a difference, glass boats would have more noise problems.

[suvowner]

No good reason to do it. It won’t measure zero anyway, and glass boats have no hull to connect to. If grounding the hull made a difference, glass boats would have more noise problems.

hmmm ok, thanks for info...

would it make a difference on a aluminum boat ?

[suvowner]

Was the power to the Troll motor turned off while you were charging your batteries? If not the bad charger could have caused the problem. If you are still getting RF on the graphs then you could have an issue with the troll motor. As said above you may also have a problem with a connection between the Boat battery and the troll motor batteries.

after switching to to the minkotta precision charger 90% of the rf is gone, but the 2 yr old and the brand new bps bps charger both show severe rf, when the bas pro charger had no rf the first 2 years. I am pretty sure never had tm turned on when charging.

so using a meter to check to check resistance or continuity would not verify whether or not there is a connection between crank and tm battery ?

how hard is it to open up and check the trolling motor ??

[Jonestrollingmotor]

If the starter is working on the outboad, the battery ground is connected to the outboard. This ground will flow through every metal part of the outboard. If the boat is aluminum, the hull will also be grounded to the outboard battery simply because the motor is grounded and clamped to the hull and aluminum is a conductor. No reason to check that with a volt/ohm meter. A glass boat is not a conductor so it's not grounded. The trolling batteries and trolling motor is on an isolated circuit from everything else. If it's an aluminum boat, the trolling motor base will be grounded, just through conductor touching conductor. With the US2, MinnKota has created a ground path from the trolling motor battery, through the control board, to the lower unit, through the US2 transducer, through the transducer cable, through depthfinder and finally to the battery the depthfinder is grounded to. Trying to place a separate ground could cause a short between batteries. This is the reason for the fuse to blow before the short damaged the transducer or depth finder. Who ever wrote the piece above posted by suvowner made some points but obviously doesn't have a clue on bassboat wiring.
John

[suvowner]

If the starter is working on the outboad, the battery ground is connected to the outboard. This ground will flow through every metal part of the outboard. If the boat is aluminum, the hull will also be grounded to the outboard battery simply because the motor is grounded and clamped to the hull and aluminum is a conductor. No reason to check that with a volt/ohm meter. A glass boat is not a conductor so it's not grounded. The trolling batteries and trolling motor is on an isolated circuit from everything else. If it's an aluminum boat, the trolling motor base will be grounded, just through conductor touching conductor. With the US2, MinnKota has created a ground path from the trolling motor battery, through the control board, to the lower unit, through the US2 transducer, through the transducer cable, through depthfinder and finally to the battery the depthfinder is grounded to. Trying to place a separate ground could cause a short between batteries. This is the reason for the fuse to blow before the short damaged the transducer or depth finder. Who ever wrote the piece above posted by suvowner made some points but obviously doesn't have a clue on bassboat wiring.
John

http://www.vexilar.com/blog/2014/08/...r-interference

goodstuff John, thank for posting I am learning so thank you.....

so if I am reading this correctly in a sense the humminbird ground is already doing what running a ground from the negative of the tm battery to the negative of the starter battery would do ?

[suvowner]

thank you Wayne for the link to the ferrite ring supplier
http://www.kf7p.com/KF7P/Ferrite_chokes.html

just got them today and 4 wraps with the pc-11 power cord to my console helix 10 cleaned up the residual rfi I was getting after replacing my bps xps charger with a min kotta precision. just need to verify with an on the water test, and with my front helix 10 gen 1 but humminbird has it right now.

[Jonestrollingmotor]

[QUOTE=suvowner;9191418
so if I am reading this correctly in a sense the MinnKota bonding wire (fuse wire) ground is already doing what running a ground from the negative of the tm battery to the negative of the starter battery would do ?[/QUOTE]

This is correct

[tweakjr]

Knock on wood my Ulterra fuse in the head hasn't blown but I'm curious about what goes wrong to cause it to trip and when it happens, what is the recommended course of action?

[CatFan]

Knock on wood my Ulterra fuse in the head hasn't blown but I'm curious about what goes wrong to cause it to trip and when it happens, what is the recommended course of action?

It blows when a connection is made between the TM batteries and the battery powering the electronics.

[tweakjr]

It blows when a connection is made between the TM batteries and the battery powering the electronics.

As in connecting 24V or 36V to the 12V electronics battery circuit?

[CatFan]

As in connecting 24V or 36V to the 12V electronics battery circuit?

Though that would do it and more, any connection between the two will blow the fuse. Connecting the negatives of both systems will blow the fuse. Using the cranking battery as part of the 24V or 36V TM string will do it. Some on the run chargers will do it.