My trolling motor will not power on.  The fuses at the batteries seem fine. I've read that you should not charge the batteries with the trolling motor plugged in. In other words, I should disconnect power if the trolling motor is not in use, charging or in storage. Apparently, that is the number 1 cause of failure and something that I just learned. What I don't know is what specific electrical problems I may have caused by charging my batteries without unplugging my trolling motor. Is the first thing I should do is replace the plug and receptacle where the trolling motor connects to the 24v system?

Correct. Unplug or switch the master switch off in the boat while charging.  Did it used to power up ?  Check all the switches, battery connections and try a voltage meter at the plug to start.  If you get about 24 volts at the plug it's in the motor's system,  then move to the pedal switches and eliminate from there.

Maybe 24 volt system is different, but I have never unplugged my TM when I charge on my 12 volt system. I do turn the speed to off and the rocker switch to off. Maybe I am going to learn something.

Minn Kota recommends unplugging their motors. I imagine Motorguide does as well. It is common practice to hard wire trolling motors to the batteries, and people have done so for many years without issue. I have always had TM's with a plug and receptacle, and I unplug mine. I will say this. If your TM is electric steer and/or has gps capabilities, unplug it. 

I have always unplugged my tm when charging. my new boat came with the Fortrex hard wired. no problems.

I never unplug mine.  It is too hard to get to.  Most of the time I throw the main power switch because of having several things in the boat that draw power even shut off.

 

My former boat of 14 years did not have a master power switch.  I never unplugged and had no problems.

I unplug mine. A trolling motor shop recommended it. They see the good the bad and the ugly, so I went with it. Isn't there an old Clint Eastwood movie in there somewhere?

Fried your control board

Older and lower end trolling motors are pretty basic. A motor and resistors to control speed. Newer units are digitally controlled and are easier to fry. My boat has master breaker switches for both the starting/house batteries and the trolling motor batteries. I always switch them off before charging.

never thought about it until this post. always thought if you shut the trolling motor off it was good to go.

I have a Minn Kota Ultrex. It was expensive.

From now on I will be flipping the trolling motor breaker before charging.

 

17 hours ago, THE_Vue's said:

Fried your control board

I'm puzzled why the inline fuses (30amp) did not protect the circuit board from frying.

15 hours ago, contium said:

Older and lower end trolling motors are pretty basic. A motor and resistors to control speed. Newer units are digitally controlled and are easier to fry. My boat has master breaker switches for both the starting/house batteries and the trolling motor batteries. I always switch them off before charging.

I'm puzzled why the inline fuses (30amp) did not protect the circuit board from frying. Would an add-on circuit breaker be a solution?

Is there a way to test the circuit board without pulling the trolling motor and taking it to a service center?

I took the head off my tm and took jumper cables to the pos and  neg with a 12v battery. if the prop turns more than likely you have a fried board. not sure if it was the right way to do it, but it diagnosed my problem 

5 hours ago, TR4321 said:

I'm puzzled why the inline fuses (30amp) did not protect the circuit board from frying.

I'm puzzled why the inline fuses (30amp) did not protect the circuit board from frying. Would an add-on circuit breaker be a solution?

Is there a way to test the circuit board without pulling the trolling motor and taking it to a service center?

 if your charger sends a voltage spike into the circuit the fuse will not stop it. A fuse only protects from over amperage.