Trolling motor problem

Ok guys, I have a head scratcher. I might know what the answer is, But it does’nt make sense to me. Last yr I put the boat away. Didnt take the batteries out, But left it plugged in. This year 1st time trying the trolling motor I have no power. I have 22.3 volts at the plug. Here’s where I’m confused. As soon as I turn on the power to the TM it blows the circuit breakers on the batteries. The motor was fine when I put it away. Not sure what size breakers they are. I’m wondering if they are just weak or do I have a short in the motor itself? TIA

Chappy

Thats a head scratcher for sure. I never leave my trolling motor plugged in for this very reason when I am not using it. Is this only a 12 volt trolling motor? Can you take the cover off the top of the motor and check voltage there?

24 volt system. Thats my next check.

I can’t really pinpoint the issue but I’d think you should have closer to 25 or 26 volts at the plug with fully charged batteries. Seems like a problem in the wiring somewhere. Corrosion somewhere?

I would imagine leaving them plugged in with some moisture in there would accelerate corrosion.

OK do you have one of those marinco trolling motor plugs that converts it from 12 to 24 bolt? My boat does. I have had the plug short out before and then only had 12 volts to the motor.

When you say turn the trolling motor on I’m assuming you mean actually turing the prop? Some trolling motors have an on off switch like an ulterra which just starts the digital components. If you were actually turning the prop on I have seen the motor housings leak water and cause corrision so when you try to start the motor its like a short causing the breaker to trip. Did you try turning your propeller by hand does it move freely? Your voltage on fully charged batteries should be 25.7. I would check the voltage at the batteries to see if there is something wrong from the batteries to the plug. I would also check the batteries at the 12 volt side which should read around 12.6. You can do this without disconnecting any wires.

The first though that comes to my mind, and it isn’t a good one, is mice. Check all your cables, and look at the wiring going down the shaft. Those critters can really cause havoc.
Another issue might be corrosion caused by a trickle of current through the wiring all winter long. See if you have continuity where it should b, and a grounded circuit.

I leave my boat plugged in through the winter too with no issues. Most problems I’ve had with minn kota trolling motors is in the lower units.

Also, like supercat asked, is it when you turn on the trolling motor, or when you try to engage the prop? If it’s when you try to engage the prop, I’m going to guess it’s lower unit troubles. Also your voltage should be higher than 22. It should be 25-26v with fully charged batteries. How old are the batteries?

I’d disconnect the batteries and test them individually. If fully charged they’re not above 12v, then somethings wrong with either your batteries or the charger. If you’re close to an auto parts store, you could bring the batteries in and have them load test them to make sure they’re not shot. I’d clean the posts up, then reconnect everything and make sure there’s good contact. Plug the charger in, and test the voltage on the batteries. It should be reading around 14v while being charged.

While talking to a friend, We’ve come to the conclusion that its either the circuit breakers or bad connections at the motor. So Im going to replace the breakers with correct apm’ed ones and clean up the battery connections really good and make sure they’re all charged up.

Chappy, If you can’t figure it out, I’ve had good luck having my Minnkota TM fixed by the Motor Clinic in Bloomington. They should be able to tell you if it is the TM or wiring in your boat.

Update…put a new circuit breaker on and a little maintenance on the batteries and it now works! Do still have a question tho… do I need a 2nd CB on a 24volt system and where would it go? On the jumper?

Just one circuit breaker is needed on the positive wire between the battery and your trolling motor.

I’m curious what lb# thrust the motor was, what size of breaker you were using and you said it worked the year before. Just seems wierd that it worked prior years and now its not working. I could see if your battery’s were low on voltage the amperage would increase causing the breaker to trip. Just curious.

Mice?

Yeah, the Motor Clinic guys are geniuses

Got it all finished up. New CB and some Battery maint. Probably a mint problem…Or lake of battery maint.