Stern thruster inoperable

One thing to do is measure the voltage at the solenoid when attempting to operate. If the voltage drops to zero from battery voltage then a bad cable termination somewhere between where you measured and the batteries.
Isn't your thruster 24 volts?
 
ttmott said:
One thing to do is measure the voltage at the solenoid when attempting to operate. If the voltage drops to zero from battery voltage then a bad cable termination somewhere between where you measured and the batteries.
Isn't your thruster 24 volts?
Click to expand...
Tested and saw drops to 7-8 volts when actuated but that was before cleaning connections. Haven’t had someone to test with since. Vetus does say drops shouldn’t be less than 10%. This is the stern thruster which is 12v. Bow is 24v
 
Irie308 said:
Tested and saw drops to 7-8 volts when actuated but that was before cleaning connections. Haven’t had someone to test with since. Vetus does say drops shouldn’t be less than 10%. This is the stern thruster which is 12v. Bow is 24v
Click to expand...
7 to 8 volts - bad! Are you sure you didn't see smoke and/or smell burning plastic with that? I hope it's all better once you can test it. I'd suggest you get some of this, but it can be difficult to find in a negative ground configuration, since it's mostly used on British machinery.
wire-harness-smoke-Custom.jpg
 
Back at the stern thruster again. So we’ve isolated to voltage drop from possible corrosion on the +\- or both. Plan was to cut the terminals off and see how far the corrosion goes up the cable. 2 buddies assisted with this today but one says replace the whole cable as the corrosion could go half way up the cable, the other says the cable doesn’t look bad after cutting it back about 3 inches. We should just determinate with new terminals and give it a whirl. To me it doesn’t seem bad and what we are seeing is the tinning on the wire. Rather not waste the money on new cabling if the problem lies in the ends. What say you?
For reference its 15' of 4/0 tinned copper.

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Seeing as a crimp connector relies on good conductivity across all of the wire strands, I'd be apprehensive to make a connection on that third image. With the heavy current needs of the thruster, you don't want to have any added resistance anywhere. I'd suggest you keep trimming back until the strands are shiny-clean, then butt-splice any additional length you need to get back to the motor and/or relays. You may find that, if the entire cable (both positive and negative) look like that, they will need to be replaced in their entirety. 'Can't say for sure from this end.
 
So I thought i had my 12 volt stern thruster back in working order but it seems it was short lived. after replacing the cable from the thruster to the solenoid and the negative from the thruster to the battery all seemed good. So much so that i thought the bow thruster was weak in comparison and turns out the batteries were on the way out. Fast forward a few months and I went to the fuel dock on a windy day so i had to lean on the thrusters more than usual. Figured i pulled all i could from the batteries so ran the gen on the way back home to charge them back up.

The Bow thruster is fine but i find the stern thruster is very weak now. When i run it it seems to have a fraction of the power it had when i first replaced the cables. Note batteries are new and i confirmed they are in good shape. I tested the voltage at the thruster and i'm down around 8 volts again under load. Tested at the battery, and both sides of the solenoid and i'm getting 10.3/10.5 under load. This thruster pulls from my port battery bank so i connected it to the starboard bank and same results.

My next plan of action is to replace the cabling on the battery side of the solenoid. But also wondering if i should be looking at the solenoid that sites in-between the cabling.
 
Irie308 said:
So I thought i had my 12 volt stern thruster back in working order but it seems it was short lived. after replacing the cable from the thruster to the solenoid and the negative from the thruster to the battery all seemed good. So much so that i thought the bow thruster was weak in comparison and turns out the batteries were on the way out. Fast forward a few months and I went to the fuel dock on a windy day so i had to lean on the thrusters more than usual. Figured i pulled all i could from the batteries so ran the gen on the way back home to charge them back up.

The Bow thruster is fine but i find the stern thruster is very weak now. When i run it it seems to have a fraction of the power it had when i first replaced the cables. Note batteries are new and i confirmed they are in good shape. I tested the voltage at the thruster and i'm down around 8 volts again under load. Tested at the battery, and both sides of the solenoid and i'm getting 10.3/10.5 under load. This thruster pulls from my port battery bank so i connected it to the starboard bank and same results.

My next plan of action is to replace the cabling on the battery side of the solenoid. But also wondering if i should be looking at the solenoid that sites in-between the cabling.
Click to expand...
Did you measure at the solenoid IN and solenoid OUT under load? That would determine if the solenoid was the issue.
 
ttmott said:
Did you measure at the solenoid IN and solenoid OUT under load? That would determine if the solenoid was the issue.
Click to expand...
Same at the solenoid as at the battery 10.3/10.5.
 
Dean had to rebuild my stern thruster just prior to selling the boat what a difference .I’m guessing your building up a lot of heat inside I doubt the cabling is to blame.
 
Havana Shamrock said:
Dean had to rebuild my stern thruster just prior to selling the boat what a difference .I’m guessing your building up a lot of heat inside I doubt the cabling is to blame.
Click to expand...
Thanks Joe, I took my cabling to be tested and there wasn't a lot of resistance. Had the ends re-terminated just in case though. I'm going to take a look at the brushes next. If they meet specs i may have to check into having it rebuilt.
 
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