Thread: Trolling Motor Wire Size, get this!?

I use two 6 gauge wires for my 70 lb MK thru a 50 amp breaker and yes the batteries are wired in series. Keep in mind that a 24V system draws ½ the current than that of an equivalent 12V system. Ohm's law.

I don't know anything about Ohm's law. You mean if you had a 55 pound thrust 12V motor, it would draw twice the amps through the wire as a 55 pound 24V motor? I guess that could make sense to me. So if 6 ga is heavy enough for a 12V 46 pound motor, surely it would be good enough for a 24V 70 pound? well shoot, that is what you got so I'm sure it is.

It's gonna be a *itch running that 6 ga wire under the rails of my Xpress boat, where the 10 ga stuff is now. Oh well, winter project maybe.

I got a 24V 50a breaker, connectors, and lugs coming for that 6 ga wire, so I'm almost ready to set up my 14' boat for fishing the 10hp lakes. I'll have better wiring in my '79 PolarKraft than in my '05 17' Xpress! for now.

Joe

Your right on track! Ohm's law is E=I/R. E=voltage, I=amps, R=resistance

i have wire dozens of trolling motors over my 25+ years of bass fishing. from 12 volt to 24 volt to 36 volt. if you use a THHN 6gauge stranded and i a 50 amp resettable breaker you should have no problems. you can buy this at most electrical supply houses. it will be cheaper than marine grade but is still very high quality. it also has a thinner tougher insulation so it is easier to pull through your boat. good luck and good fishing.

I am an electrician and I have a little pocket cheat book for finding what wire size I need for jobs where I have devices that I know the ampacity or amps of equipment. Different insulation material and number of strands in the wire gives the wire a different maximum amp rating. For example regular copper insulated with THHN has a lower amp rating than what we use on robotic welders which is MHW which I call railroad wire. Here is a link for what wire is good for what amps.

http://wiki.xtronics.com/index.php/W..._or_ampacities

Your breaker needs to be rated at or below the rating in the chart. #6 is good for 60 amps but you want to fuse it at about 50.

Hey Joe,
I have a 2001 17' Xpress X-51. I just changed my 36 pound 12 volt Motorguide motor over to a 70 pound 24 volt Minn- Kota. My boat had another set of wires already run to the back with inline fuses for 12-24 volt systems. These wires were tucked up out of the way,Had to look for them, your rig may have these as well. On my 12 volt motor the plug was wired to the black- and red+ leads, For the 24 volt motor I wired Black- and orange +. If you have a meter, check this on your boat before wiring to verify.
If you don't have the other set, wiring the batteries in series will work.
IBNFSHN knows his stuff! He has helped alot of folks with electrical problems.
Good Luck!

Crappie Stalker, I'll look for the extra wires but I think I'm out of luck there. Especially since what I have is only 10ga.

Sparky, not sure I should take advice from an electrician who calls himself Sparky!

Seriously,
My 46 pound motor draws a hypothetical 46 amps, based on manufacture rule of thumb 1 pound of thrust takes 1 amp. They are sandbagging because it has a 40 amp fuse and never blown, and it has 10 ga wire.

Now here is gets dicey. A new 70 pound thrust 24V motor should only draw a hypothetical 1/2 amp per pound of thrust because of the doubled voltage? I'm not sure if this is right...the ampacity chart you linked to doesn't specify voltage. But it does say that 10 ga wire will carry 33-55 amps. It sounds like based on that, my 10 ga wire could carry 35 amps safely at 24V. Am I way off here? Or is it a no-brainer that I have to spend at least $75 on new wire and terminals to run for the bigger motor.

6 gauge wire seems like such overkill....when the motor itself and the male/female connectors are using 10 ga.

Joe

Joe, you have got to take in consideration the max amps the circuit may need AND the distance away. Go here http://www.powerstream.com/Wire_Size.htm and page down to the voltage drop calculator. Plug in your figures and you can see what you need. You want to achieve a voltage drop of less than 1 volt. The lower the better.