Blowing Circuit Breaker on Trolling Motor

[Alpinegold]

I have a Motorguide 550 Brute 41 # thrust that came with a 1979 Ranger V178. I feel like there is integrety in the wiring panel at the front of the boat. It has 4 wires coming from the back of the boat. The plug that goes to the trolling motor is 3 prong. My question is how do I wire the batteries in the back. I am wanting 12 / 24 v system. Have cranking battery and two batteries for the trolling motor. The front panel has 12 / 24 charging switch. The on / off comes from a foot switch. It appears to be just a loop of negative, The system never had a battery switch so I would like to avoid that. On the head of the trolling motor, it has a 24/12 / off switch.

I have wired a stardard 12/24 3 wire hook up using a cross pole.

Here is my problem: When I run the motor with a load at the highest setting in 24 v mode, I blow the 30 amp circuit breaker within 30 secounds. 0

I'm thinking I need to increase the size of wire from the back of the boat to the circuit breakers in the front of the boat. However this is the orginal wiring and orginal trolling motor. Since the orginal configureation was a 4 wire set up going into a circuit breaker and to a charge run switch and then to the plug would there have been less heat disapated in the 4 wire set up than the 3 wire set up that I am currently using.

Also if I increase the size of wire coming from the battery could that mess up the trolling motor?

 

[hankll]

Re: Blowing Circuit Breaker on Trolling Motor

Did you take prop off and check for fishing line wrapped up behind it? I wrapped up a fishing line into mine and it still worked but made a mental note to take my prop off when I got home to get it out. What I found was a whole lot more than just what I had done, and there was quite a nest of line wrapped up. Or it could be something in the motor that is dragging and pulling to much power and blowing the fuse.

 

[jtexas]

Re: Blowing Circuit Breaker on Trolling Motor

Increasing the wire size never hurts, but it won't make any difference to the circuit breaker.

A motor's peak amp draw happens during startup. If 30 amps is the recommended breaker size, and it's tripping during normal operation, something is wrong. Fishing line is likely.

Are you sure it's a *24-volt* 30-amp circuit breaker?

Also note that each time it's tripped, a circuit breaker gets a little easier to trip.

 

[tashasdaddy]

Re: Blowing Circuit Breaker on Trolling Motor

i think it has the wrong breaker, check what it calls for. mine has a 50 amp breaker.

 

[Alpinegold]

Re: Blowing Circuit Breaker on Trolling Motor

Thanks for your help guys. I took the prop off and there is no line wrapped around any where. It was very clean.

Tashsdaddy I am pretty certain the boat came from ranger with the 30 amp circuit breaker as it is built into the front panel.

This one really has me stumped. My thinking is if I increase to a 50 amp fuse, I could burn that little motor up.

 

[Barnacle_Bill]

Re: Blowing Circuit Breaker on Trolling Motor

30 amp breaker is not enough for that motor. A 41lb thrust motor operating on 12VDC can draw a max of approximately 41 amps. You need a 50 amp breaker.

 

[TerryMSU]

Re: Blowing Circuit Breaker on Trolling Motor

To put things in perspective, I just got a 12Volt 40Lb Minnkota. It recommended using a 60 Amp manual reset circuit breaker. I am using a 50 Amp auto reset breaker because that is what the local boat shop had available. If you are drawing 60 amps, that 30 amp breaker will trip in about 30 Seconds.

As far as wire size, larger size (Smaller number) is always better.

See the following for a decent wire size vs. current capacity rating chart

http://www.eskimo.com/~billb/tesla/wire1.txt

One thing that concerns me about your system...

I think that the 12 volt system should draw more current than the 24 volt system. This assumes that there is a switch for 12/24 volt operation. If so, the 12 amp system should trip even faster. Is it possible that you have the 12/24 volt switch in the wrong position? If so, that would account for tripping the breaker.

One more question... How are you loading the motor? If it is not in the water and turning a prop, the load may be wrong. Does this happen in the water?

TerryMSU

 

[jtexas]

Re: Blowing Circuit Breaker on Trolling Motor

Your typical 12V motorguide peak draw is 48, 24V is 38. Spec might've changed with the recent semiconductor-controlled models, but that'll be about right for a '79.

Those are the numbers I'd use if I couldn't find anything more specific to my particular model.

Obviously peak draw happens at start-up or under the heaviest load. So I wouldn't doubt you could go years never blowing a 30-amp breaker.

Motor gets older, starts dragging a little, draws more amps.

Implication here is that you want different sized breakers on the 12V and 24V leads.

Google "awg wiring charts", you can find out what size wire would be optimal for your setup. I'd trust ranger to use the right wiring but after all these years in adverse conditions, well, you know......

 

[fire831]

Re: Blowing Circuit Breaker on Trolling Motor

My 1978 67 Brute Motor Guide does the same thing. Has two sets of wires going to the front and go into the panel where you plug the motor in. Forgot to mention it's a 1978 ProCraft. When I run 24 volt pops both inline 30 amp fuses. Run it on 12 volt and she'll run all day. I changed the ends on the wires because they looked bad and also put new inline fuse holders on but have not ran on 24 volt yet to see if it was a fix or not.

 

[Alpinegold]

Re: Blowing Circuit Breaker on Trolling Motor

I want to thank everone for your help. I'm going to replace the circuit breakers and will replace my wiring. I will let you know how it all washes.

Alpinegold